Quantum state transfer via a two-qubit Heisenberg XXZ spin model
Energy Technology Data Exchange (ETDEWEB)
Liu Jia; Zhang Guofeng [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); Chen Ziyu [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China)], E-mail: chenzy@buaa.edu.cn
2008-04-14
Transfer of quantum states through a two-qubit Heisenberg XXZ spin model with a nonuniform magnetic field b is investigated by means of quantum theory. The influences of b, the spin exchange coupling J and the effective transfer time T=Jt on the fidelity have been studied for some different initial states. Results show that fidelity of the transferred state is determined not only by J, T and b but also by the initial state of this quantum system. Ideal information transfer can be realized for some kinds of initial states. We also found that the interactions of the z-component J{sub z} and uniform magnetic field B do not have any contribution to the fidelity. These results may be useful for quantum information processing.
XYZ Quantum Heisenberg Models with p-Orbital Bosons
DEFF Research Database (Denmark)
Pinheiro, Fernanda; Bruun, Georg; Martikainen, Jani-Petri
2013-01-01
We demonstrate how the spin-1/2 XYZ quantum Heisenberg model can be realized with bosonic atoms loaded in the p band of an optical lattice in the Mott regime. The combination of Bose statistics and the symmetry of the p-orbital wave functions leads to a nonintegrable Heisenberg model...... with antiferromagnetic couplings. Moreover, the sign and relative strength of the couplings characterizing the model are shown to be experimentally tunable. We display the rich phase diagram in the one-dimensional case and discuss finite size effects relevant for trapped systems. Finally, experimental issues related...
International Nuclear Information System (INIS)
Zhang, Guo-Feng
2007-01-01
Thermal entanglement of a two-qubit Heisenberg chain in the presence of the Dzyaloshinski-Moriya (DM) anisotropic antisymmetric interaction and entanglement teleportation when using two independent Heisenberg chains as the quantum channel are investigated. It is found that the DM interaction can excite entanglement and teleportation fidelity. The output entanglement increases linearly with increasing value of the input; its dependences on the temperature, DM interaction, and spin coupling constant are given in detail. Entanglement teleportation will be better realized via an antiferromagnetic spin chain when the DM interaction is turned off and the temperature is low. However, the introduction of the DM interaction can cause the ferromagnetic spin chain to be a better quantum channel for teleportation. A minimal entanglement of the thermal state in the model is needed to realize the entanglement teleportation regardless of whether the spin chains are antiferromagnetic or ferromagnetic
Peng, Hu-Ping; Fang, Mao-Fa; Yu, Min; Zou, Hong-Mei
2018-03-01
We study the influences of quantum coherence on the positive work and the efficiency of quantum heat engine (QHE) based on working substance of two-qubit Heisenberg model under a constant external magnetic field. By using analytical and numerical solution, we give the relation expressions for both the positive work and the efficiency with quantum coherence, and in detail discuss the effects of the quantum coherence on the positive work and the efficiency of QHE in the absence or presence of external magnetic field, respectively.
Wang, Dong; Huang, Aijun; Ming, Fei; Sun, Wenyang; Lu, Heping; Liu, Chengcheng; Ye, Liu
2017-06-01
The uncertainty principle provides a nontrivial bound to expose the precision for the outcome of the measurement on a pair of incompatible observables in a quantum system. Therefore, it is of essential importance for quantum precision measurement in the area of quantum information processing. Herein, we investigate quantum-memory-assisted entropic uncertainty relation (QMA-EUR) in a two-qubit Heisenberg \\boldsymbol{X}\\boldsymbol{Y}\\boldsymbol{Z} spin chain. Specifically, we observe the dynamics of QMA-EUR in a realistic model there are two correlated sites linked by a thermal entanglement in the spin chain with an inhomogeneous magnetic field. It turns out that the temperature, the external inhomogeneous magnetic field and the field inhomogeneity can lift the uncertainty of the measurement due to the reduction of the thermal entanglement, and explicitly higher temperature, stronger magnetic field or larger inhomogeneity of the field can result in inflation of the uncertainty. Besides, it is found that there exists distinct dynamical behaviors of the uncertainty for ferromagnetism \\boldsymbol{}≤ft(\\boldsymbol{J}\\boldsymbol{0}\\right) chains. Moreover, we also verify that the measuring uncertainty is dramatically anti-correlated with the purity of the bipartite spin system, the greater purity can result in the reduction of the measuring uncertainty, vice versa. Therefore, our observations might provide a better understanding of the dynamics of the entropic uncertainty in the Heisenberg spin chain, and thus shed light on quantum precision measurement in the framework of versatile systems, particularly solid states.
Ground state of a spin-1/2 Heisenberg-Ising two-leg ladder with XYZ intra-rung coupling
Directory of Open Access Journals (Sweden)
T. Verkholyak
2013-03-01
Full Text Available The quantum spin-1/2 two-leg ladder with an anisotropic XYZ Heisenberg intra-rung interaction and Ising inter-rung interactions is treated by means of a rigorous approach based on the unitary transformation. The particular case of the considered model with X-X intra-rung interaction resembles a quantum compass ladder with additional frustrating diagonal Ising interactions. Using an appropriately chosen unitary transformation, the model under investigation may be reduced to a transverse Ising chain with composite spins, and one may subsequently find the ground state quite rigorously. We obtain a ground-state phase diagram and analyze the interplay of the competition between several factors: the XYZ anisotropy in the Heisenberg intra-rung coupling, the Ising interaction along the legs, and the frustrating diagonal Ising interaction. The investigated model shows extraordinarily diverse ground-state phase diagrams including several unusual quantum ordered phases, two different disordered quantum paramagnetic phases, as well as discontinuous or continuous quantum phase transitions between those phases.
Projective Ring Line Encompassing Two-Qubits
Czech Academy of Sciences Publication Activity Database
Saniga, M.; Planat, M.; Pracna, Petr
2008-01-01
Roč. 155, č. 3 (2008), s. 905-913 ISSN 0040-5779 R&D Projects: GA AV ČR 1ET400400410 Institutional research plan: CEZ:AV0Z40400503 Keywords : two-qubits * projective ring line * generalized quadrangle of order two Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.721, year: 2008
Influence of magnetic field on swap operation in Heisenberg XXZ model
Energy Technology Data Exchange (ETDEWEB)
Liu Jia [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); Zhang Guofeng, E-mail: gf1978zhang@buaa.edu.c [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); Chen Ziyu [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China)
2009-05-01
Swap operation based on a two-qubit Heisenberg XXZ model under a uniform magnetic field in arbitrary direction and magnitude is investigated. It is shown that swap gate can be implemented on some conditions and its feasibility is established.
Influence of magnetic field on swap operation in Heisenberg XXZ model
International Nuclear Information System (INIS)
Liu Jia; Zhang Guofeng; Chen Ziyu
2009-01-01
Swap operation based on a two-qubit Heisenberg XXZ model under a uniform magnetic field in arbitrary direction and magnitude is investigated. It is shown that swap gate can be implemented on some conditions and its feasibility is established.
The two-qubit quantum Rabi model: inhomogeneous coupling
International Nuclear Information System (INIS)
Mao, Lijun; Huai, Sainan; Zhang, Yunbo
2015-01-01
We revisit the analytic solution of the two-qubit quantum Rabi model with inhomogeneous coupling and transition frequencies using a displaced oscillator basis. This approach enables us to apply the same truncation rules and techniques adopted in the Rabi model to the two qubits system. The derived analytical spectra match perfectly with the numerical solutions in the parameter regime where the qubits’ transition frequencies are far off-resonance with the field frequency and the interaction strengths reach the ultrastrong coupling regime. We further explore the dynamical behavior of the two qubits as well as the evolution of entanglement. The analytical methods provide unexpectedly accurate results in describing the dynamics of the two qubits in the present experimentally accessible coupling regime. The time evolutions of the probability for the qubits show that the collapse-revival phenomena emerge, survive and finally disappear when one coupling strength increases from weak to strong coupling regimes and the other coupling strength is well into the ultrastrong coupling regime. The inhomogeneous coupling system exhibits new dynamics, which are different from the homogeneous coupling case. (paper)
Atomic Evolution and Entanglement of Two Qubits in Photon Superfluid
Yin, Miao; Zhang, Xiongfeng; Deng, Yunlong; Deng, Huaqiu
2018-03-01
By using reservoir theory, we investigate the evolution of an atom placed in photon superfluid and study the entanglement properties of two qubits interacting with photon superfluid. It is found that the atomic decay rate in photon superfluid changes periodically with position of the atom and the decay rate can be inhibited compared to that in usual electromagnetic environment without photon superfluid. It is also found that when two atoms are separately immersed in their own local photon-superfluid reservoir, the entanglement sudden death or birth occurs or not only depends on the initial state of the qubits. What is more, we find a possible case that the concurrence between two qubits can remain a constant value by choosing proper values of parameters of the system, which may provide a new way to preserve quantum entanglement.
Silicon photonic processor of two-qubit entangling quantum logic
Santagati, R.; Silverstone, J. W.; Strain, M. J.; Sorel, M.; Miki, S.; Yamashita, T.; Fujiwara, M.; Sasaki, M.; Terai, H.; Tanner, M. G.; Natarajan, C. M.; Hadfield, R. H.; O'Brien, J. L.; Thompson, M. G.
2017-11-01
Entanglement is a fundamental property of quantum mechanics, and is a primary resource in quantum information systems. Its manipulation remains a central challenge in the development of quantum technology. In this work, we demonstrate a device which can generate, manipulate, and analyse two-qubit entangled states, using miniature and mass-manufacturable silicon photonics. By combining four photon-pair sources with a reconfigurable six-mode interferometer, embedding a switchable entangling gate, we generate two-qubit entangled states, manipulate their entanglement, and analyse them, all in the same silicon chip. Using quantum state tomography, we show how our source can produce a range of entangled and separable states, and how our switchable controlled-Z gate operates on them, entangling them or making them separable depending on its configuration.
Negativity of Two-Qubit System Through Spin Coherent States
International Nuclear Information System (INIS)
Berrada, K.; El Baz, M.; Hassouni, Y.; Eleuch, H.
2009-12-01
Using the negativity, we express and analyze the entanglement of two-qubit nonorthogonal pure states through the spin coherent states. We formulate this measure in terms of the amplitudes of coherent states and we give the conditions for the minimal and the maximal entanglement. We generalize this formalism to the case of a class of mixed states and show that the negativity is also a function of probabilities. (author)
A programmable two-qubit quantum processor in silicon
Watson, T. F.; Philips, S. G. J.; Kawakami, E.; Ward, D. R.; Scarlino, P.; Veldhorst, M.; Savage, D. E.; Lagally, M. G.; Friesen, Mark; Coppersmith, S. N.; Eriksson, M. A.; Vandersypen, L. M. K.
2018-03-01
Now that it is possible to achieve measurement and control fidelities for individual quantum bits (qubits) above the threshold for fault tolerance, attention is moving towards the difficult task of scaling up the number of physical qubits to the large numbers that are needed for fault-tolerant quantum computing. In this context, quantum-dot-based spin qubits could have substantial advantages over other types of qubit owing to their potential for all-electrical operation and ability to be integrated at high density onto an industrial platform. Initialization, readout and single- and two-qubit gates have been demonstrated in various quantum-dot-based qubit representations. However, as seen with small-scale demonstrations of quantum computers using other types of qubit, combining these elements leads to challenges related to qubit crosstalk, state leakage, calibration and control hardware. Here we overcome these challenges by using carefully designed control techniques to demonstrate a programmable two-qubit quantum processor in a silicon device that can perform the Deutsch–Josza algorithm and the Grover search algorithm—canonical examples of quantum algorithms that outperform their classical analogues. We characterize the entanglement in our processor by using quantum-state tomography of Bell states, measuring state fidelities of 85–89 per cent and concurrences of 73–82 per cent. These results pave the way for larger-scale quantum computers that use spins confined to quantum dots.
A programmable two-qubit quantum processor in silicon.
Watson, T F; Philips, S G J; Kawakami, E; Ward, D R; Scarlino, P; Veldhorst, M; Savage, D E; Lagally, M G; Friesen, Mark; Coppersmith, S N; Eriksson, M A; Vandersypen, L M K
2018-03-29
Now that it is possible to achieve measurement and control fidelities for individual quantum bits (qubits) above the threshold for fault tolerance, attention is moving towards the difficult task of scaling up the number of physical qubits to the large numbers that are needed for fault-tolerant quantum computing. In this context, quantum-dot-based spin qubits could have substantial advantages over other types of qubit owing to their potential for all-electrical operation and ability to be integrated at high density onto an industrial platform. Initialization, readout and single- and two-qubit gates have been demonstrated in various quantum-dot-based qubit representations. However, as seen with small-scale demonstrations of quantum computers using other types of qubit, combining these elements leads to challenges related to qubit crosstalk, state leakage, calibration and control hardware. Here we overcome these challenges by using carefully designed control techniques to demonstrate a programmable two-qubit quantum processor in a silicon device that can perform the Deutsch-Josza algorithm and the Grover search algorithm-canonical examples of quantum algorithms that outperform their classical analogues. We characterize the entanglement in our processor by using quantum-state tomography of Bell states, measuring state fidelities of 85-89 per cent and concurrences of 73-82 per cent. These results pave the way for larger-scale quantum computers that use spins confined to quantum dots.
Secret key distillation from shielded two-qubit states
International Nuclear Information System (INIS)
Bae, Joonwoo
2010-01-01
The quantum states corresponding to a secret key are characterized using the so-called private states, where the key part consisting of a secret key is shielded by the additional systems. Based on the construction, it was shown that a secret key can be distilled from bound entangled states. In this work, I consider the shielded two-qubit states in a key-distillation scenario and derive the conditions under which a secret key can be distilled using the recurrence protocol or the two-way classical distillation, advantage distillation together with one-way postprocessing. From the security conditions, it is shown that a secret key can be distilled from bound entangled states in a much wider range. In addition, I consider the case that in which white noise is added to quantum states and show that the classical distillation protocol still works despite a certain amount of noise although the recurrence protocol does not.
Integrability and solvability of the simplified two-qubit Rabi model
International Nuclear Information System (INIS)
Peng Jie; Ren Zhongzhou; Guo Guangjie; Ju Guoxing
2012-01-01
The simplified two-qubit Rabi model is proposed and its analytical solution is presented. There are no level crossings in the spectral graph of the model, which indicates that it is not integrable. The criterion of integrability for the Rabi model proposed by Braak (2011 Phys. Rev. Lett. 107 100401) is also used for the simplified two-qubit Rabi model and the same conclusion, consistent with what the spectral graph shows, can be drawn, which indicates that the criterion remains valid when applied to the two-qubit case. The simplified two-qubit Rabi model is another example of a non-integrable but exactly solvable system except for the generalized Rabi model. (paper)
Two-qubit gate operations in superconducting circuits with strong coupling and weak anharmonicity
International Nuclear Information System (INIS)
Lü Xinyou; Ashhab, S; Cui Wei; Wu Rebing; Nori, Franco
2012-01-01
We theoretically study the implementation of two-qubit gates in a system of two coupled superconducting qubits. In particular, we analyze two-qubit gate operations under the condition that the coupling strength is comparable with or even larger than the anharmonicity of the qubits. By numerically solving the time-dependent Schrödinger equation under the assumption of negligible decoherence, we obtain the dependence of the two-qubit gate fidelity on the system parameters in the case of both direct and indirect qubit-qubit coupling. Our numerical results can be used to identify the ‘safe’ parameter regime for experimentally implementing two-qubit gates with high fidelity in these systems. (paper)
DEFF Research Database (Denmark)
Tosco, Paolo; Balle, Thomas; Shiri, Fereshteh
2011-01-01
An open-source tool capable of converting SD files (and virtually any other format through OpenBabel) into MMFF-typed XYZ coordinate files to be used with TINKER is described. SDF2XYZ2SDF allows including the power of TINKER molecular mechanics computations in automated cheminformatics workflows...
Correlations, Nonlocality and Usefulness of an Efficient Class of Two-Qubit Mixed Entangled States
Singh, Parvinder; Kumar, Atul
2018-02-01
We establish an analytical relation between the Bell-Clauser-Horne-Shimony-Holt (Bell-CHSH) inequality and weak measurement strengths under noisy conditions. We show that the analytical results obtained in this article are of utmost importance for proposing a new class of two-qubit mixed states for quantum information processing. Our analysis further shows that the states proposed here are better resources for quantum information in comparison to other two-qubit mixed entangled states.
DEFF Research Database (Denmark)
Tosco, Paolo; Balle, Thomas
2011-01-01
Description sdf2xyz2sdf is an open-source software aimed at converting SDF files into TINKER XYZ files (and viceversa) while performing automatic assignment of MMFF94 atom types, bond types and charges. The sdf2xyz2sdf package consists of two programs: •sdf2tinkerxyz •tinkerxyz2sdf sdf2xyz2sdf...... depends on OpenBabel for MMFF atom type and charge assignment. Since input to sdf2tinkerxyz is entered through standard input, and output from tinkerxyz2sdf is printed on standard output, it is possible to pipe output from OpenBabel into sdf2tinkerxyz, or to pipe tinkerxyz2sdf output into OpenBabel, so...... that virtually any format conversion from/to TINKER XYZ may be accomplished. Interestingly, also ionic heteroaromatic rings which could not be assigned proper charges by the original TINKER-MMFF code are correctly accounted for by sdf2xyz2sdf....
A two-qubit photonic quantum processor and its application to solving systems of linear equations
Barz, Stefanie; Kassal, Ivan; Ringbauer, Martin; Lipp, Yannick Ole; Dakić, Borivoje; Aspuru-Guzik, Alán; Walther, Philip
2014-01-01
Large-scale quantum computers will require the ability to apply long sequences of entangling gates to many qubits. In a photonic architecture, where single-qubit gates can be performed easily and precisely, the application of consecutive two-qubit entangling gates has been a significant obstacle. Here, we demonstrate a two-qubit photonic quantum processor that implements two consecutive CNOT gates on the same pair of polarisation-encoded qubits. To demonstrate the flexibility of our system, we implement various instances of the quantum algorithm for solving of systems of linear equations. PMID:25135432
Concurrence Measurement for the Two-Qubit Optical and Atomic States
Directory of Open Access Journals (Sweden)
Lan Zhou
2015-06-01
Full Text Available Concurrence provides us an effective approach to quantify entanglement, which is quite important in quantum information processing applications. In the paper, we mainly review some direct concurrence measurement protocols of the two-qubit optical or atomic system. We first introduce the concept of concurrence for a two-qubit system. Second, we explain the approaches of the concurrence measurement in both a linear and a nonlinear optical system. Third, we introduce some protocols for measuring the concurrence of the atomic entanglement system.
Coxeter groups A4, B4 and D4 for two-qubit systems
Indian Academy of Sciences (India)
physics pp. 247–260. Coxeter groups A4, B4 and D4 for two-qubit systems. RAMAZAN KOÇ1,∗. , M YAKUP HACIIBRAHIMO ˇGLU1 and MEHMET KOCA2 ... reflection matrices. The von Neumann entropy of each reduced density matrix is calculated. It is shown that these unitary matrix representations are naturally related to ...
Two qubits for C.G. Jung’s theory of personality
Blutner, R.; Hochnadel, E.
2010-01-01
We propose a formalization of C.G. Jung’s theory of personality using a four-dimensional Hilbert-space for the representation of two qubits. The first qubit relates to Jung’s four psychological functions: Thinking, Feeling, Sensing and iNtuition, which are represented by two groups of projection
Coxeter groups A4, B4 and D4 for two-qubit systems
Indian Academy of Sciences (India)
Abstract. The Coxeter–Weyl groups W(A4), W(B4) and W(D4) have proven very useful for two-qubit systems in quantum information theory. A simple technique is employed to construct the unitary matrix representations of the groups, based on quaternionic transformation of the usual reflection matrices. The von Neumann ...
Optimal measurements to access classical correlations of two-qubit states
Lu, Xiao-Ming; Ma, Jian; Xi, Zhengjun; Wang, Xiaoguang
2011-01-01
We analyze the optimal measurements to access classical correlations in arbitrary two-qubit states. Two-qubit states can be transformed into the canonical forms via local unitary operations. For the canonical forms, we investigate the probability distribution of the optimal measurements. The probability distribution of the optimal measurements is found to be centralized in the vicinity of a specific von Neumann measurement, which we call the maximal-correlation-direction measurement (MCDM). We prove that, for the states with zero discord and maximally mixed marginals, the MCDM is the optimal measurement. Furthermore, we give an upper bound of quantum discord based on the MCDM, and investigate its performance for approximating the quantum discord.
Probabilistic Teleportation of Arbitrary Two-Qubit Quantum State via Non-Symmetric Quantum Channel
Directory of Open Access Journals (Sweden)
Kan Wang
2018-03-01
Full Text Available Quantum teleportation has significant meaning in quantum information. In particular, entangled states can also be used for perfectly teleporting the quantum state with some probability. This is more practical and efficient in practice. In this paper, we propose schemes to use non-symmetric quantum channel combinations for probabilistic teleportation of an arbitrary two-qubit quantum state from sender to receiver. The non-symmetric quantum channel is composed of a two-qubit partially entangled state and a three-qubit partially entangled state, where partially entangled Greenberger–Horne–Zeilinger (GHZ state and W state are considered, respectively. All schemes are presented in detail and the unitary operations required are given in concise formulas. Methods are provided for reducing classical communication cost and combining operations to simplify the manipulation. Moreover, our schemes are flexible and applicable in different situations.
Remark on the One-Way Quantum Deficit for General Two-Qubit States
International Nuclear Information System (INIS)
Shao Lian-He; Xi Zheng-Jun; Li Yong-Ming
2013-01-01
We reinvestigate the one-way quantum deficit, which is a measure of quantum correlation emerging from a thermodynamical approach. We give a tight upper bound of the one-way quantum deficit for general mixed states, and give a sufficient condition for this bound. Finally, we discuss a universal way to evaluate the one-way quantum deficit for general two-qubit states. (general)
Manipulating the sudden death of entanglement in two-qubit atomic systems
Energy Technology Data Exchange (ETDEWEB)
Hussain, Mahmood Irtiza; Tahira, Rabia; Ikram, Manzoor [COMSATS Institute of Information Technology, Islamabad (Pakistan)
2011-10-15
We investigate the entanglement dynamics of a general two-qubit system in a noisy environment presenting analytical descriptions of the time evolution of entanglement having some unitary operations after its evolution in dissipative environments. We show that quantum gates (unitary operators) and bath switching can change the subsequent dynamics of entanglement. For this purpose, we consider {sigma}{sub x} and bath switching operations that change the disentanglement time from finite to infinite.
Manipulating the sudden death of entanglement in two-qubit atomic systems
International Nuclear Information System (INIS)
Hussain, Mahmood Irtiza; Tahira, Rabia; Ikram, Manzoor
2011-01-01
We investigate the entanglement dynamics of a general two-qubit system in a noisy environment presenting analytical descriptions of the time evolution of entanglement having some unitary operations after its evolution in dissipative environments. We show that quantum gates (unitary operators) and bath switching can change the subsequent dynamics of entanglement. For this purpose, we consider σ x and bath switching operations that change the disentanglement time from finite to infinite.
Protecting unknown two-qubit entangled states by nesting Uhrig's dynamical decoupling sequences
International Nuclear Information System (INIS)
Mukhtar, Musawwadah; Soh, Wee Tee; Saw, Thuan Beng; Gong, Jiangbin
2010-01-01
Future quantum technologies rely heavily on good protection of quantum entanglement against environment-induced decoherence. A recent study showed that an extension of Uhrig's dynamical decoupling (UDD) sequence can (in theory) lock an arbitrary but known two-qubit entangled state to the Nth order using a sequence of N control pulses [Mukhtar et al., Phys. Rev. A 81, 012331 (2010)]. By nesting three layers of explicitly constructed UDD sequences, here we first consider the protection of unknown two-qubit states as superposition of two known basis states, without making assumptions of the system-environment coupling. It is found that the obtained decoherence suppression can be highly sensitive to the ordering of the three UDD layers and can be remarkably effective with the correct ordering. The detailed theoretical results are useful for general understanding of the nature of controlled quantum dynamics under nested UDD. As an extension of our three-layer UDD, it is finally pointed out that a completely unknown two-qubit state can be protected by nesting four layers of UDD sequences. This work indicates that when UDD is applicable (e.g., when the environment has a sharp frequency cutoff and when control pulses can be taken as instantaneous pulses), dynamical decoupling using nested UDD sequences is a powerful approach for entanglement protection.
Environmental Effects on Two-Qubit Correlation in the Dispersive Jaynes-Cummings Model
Ban, Masashi
2018-02-01
Total, classical and quantum correlations as well as entanglement are studied for a two-qubit system, where each qubit is placed in a micro cavity described by the dispersive Jaynes-Cummings model. Not only the loss of cavity photons but also the effect of the qubit-photon interaction on the loss is taken into account. The two-qubit system is initially prepared in a Bell diagonal state with a single mixing parameter and the cavity photon is either in a superposition of vacuum and single-photon states or in a weak coherent state. It is shown that more correlation of the two qubits can survive as an initial value of the cavity photon number is smaller. There is a threshold value of the cavity photon number, below which the stationary state becomes inseparable. Furthermore it is found that the external environment which causes the cavity loss has two effects; one brings about the decay of the correlations and the other suppresses the decay.
Perumusan Strategi Bisnis PT XYZ
Directory of Open Access Journals (Sweden)
Roy Hutahaean
2017-09-01
Full Text Available The purpose of this study is to formulate business strategy of XYZ Company. This study used 4 analysis tool Matrixes i.e. IFE (Internal Factor Evaluation and EFE (External Factor Evaluation, SWOT (Strength, Weaknesses, Opportunities, and Threat, and QPSM (Quantitative Strategic Planning Matrix. The primary and secondary data were used for this study. The IFE and EFE analysis showed weighted values of 2.52; 3.31 in quadrant II, indicating that this company is still in growth and development phase while, through the SWOT analysis, 5 alternative strategies could be concluded i.e. (1 collaboration with government to provide special fleet as domestic transportation to support national shipping industry; (2 collaboration not only with Head company but also with the other multi-stakeholders; (3 Capacity building regarding development of national shipping industry to XYZ employees; (4 establishment of agreement among multi-stakeholders against corruptions, collusion and nepotism; (5 development of a good working mechanism in accordance with the structural organization to increase working efficiency. Lastly, based on QPSM analysis, the main priority in business strategy of XYZ Co. is the capacity building for all of its employees.Keywords: business strategy, IFE,EFE, SWOT Matrix, QSPMAbstrak: Penelitian ini bertujuan memformulasikan strategi bisnis PT. XYZ melalui pendekatan analisis deskriptif. Alat alat analisis yang digunakan, yaitu matrix IFE (Internal factor Evaluation dan EFE (External Factor Evaluation, SWOT (Strength, Weaknesses, Opportunities, and Threat dan QSPM (Quantitative Strategic Planning Matrix. Data yang digunakan adalah data primer dan sekunder. Berdasarkan hasil IFE dan EFE diperoleh nilai tertimbang masing masing sebesar (2,523;3,310 sehingga posisi perusahaan dalam matriks IE berada di kuadran II, yaitu tumbuh dan kembangkan. Berdasarkan hasil analisis SWOT diperoleh lima alternatif strategi (1 bekerja sama dengan pemerintah dalam
Heisenberg's Invention of Matrices
Indian Academy of Sciences (India)
seek help from Heisenberg's 1925 paper, in order to reduce the weirdness of going from classical observables to quantum operators. It is well known that quantum ... these strange but basic concepts can be understood from Heisenberg's famous 1925 paper, which is considered as the birth of modern quantum mechanics.
Speed of quantum evolution of entangled two qubits states: Local vs. global evolution
Energy Technology Data Exchange (ETDEWEB)
Curilef, S [Departamento de Fisica, Universidad Catolica del Norte, Antofagasta (Chile); Zander, C; Plastino, A R [Physics Department, University of Pretoria, Pretoria 0002 (South Africa)], E-mail: arplastino@maple.up.ac.za
2008-11-01
There is a lower bound for the 'speed' of quantum evolution as measured by the time needed to reach an orthogonal state. We show that, for two-qubits systems, states saturating the quantum speed limit tend to exhibit a small amount of local evolution, as measured by the fidelity between the initial and final single qubit states after the time {tau} required by the composite system to reach an orthogonal state. Consequently, a trade-off between the speed of global evolution and the amount of local evolution seems to be at work.
Measurement-induced two-qubit entanglement in a bad cavity: Fundamental and practical considerations
DEFF Research Database (Denmark)
Julsgaard, Brian; Mølmer, Klaus
2012-01-01
An entanglement-generating protocol is described for two qubits coupled to a cavity field in the bad-cavity limit. By measuring the amplitude of a field transmitted through the cavity, an entangled spin-singlet state can be established probabilistically. Both fundamental limitations and practical...... measurement schemes are discussed, and the influence of dissipative processes and inhomogeneities in the qubits are analyzed. The measurement-based protocol provides criteria for selecting states with an infidelity scaling linearly with the qubit-decoherence rate....
Measurement-induced two-qubit entanglement in a bad cavity: Fundamental and practical considerations
Julsgaard, Brian; Mølmer, Klaus
2012-03-01
An entanglement-generating protocol is described for two qubits coupled to a cavity field in the bad-cavity limit. By measuring the amplitude of a field transmitted through the cavity, an entangled spin-singlet state can be established probabilistically. Both fundamental limitations and practical measurement schemes are discussed, and the influence of dissipative processes and inhomogeneities in the qubits are analyzed. The measurement-based protocol provides criteria for selecting states with an infidelity scaling linearly with the qubit-decoherence rate.
One-Way Information Deficit and Geometry for a Class of Two-Qubit States
International Nuclear Information System (INIS)
Wang Yaokun; Ma Teng; Wang Zhixi; Li Bo
2013-01-01
The work deficit, as introduced by Jonathan Oppenheim et al. [Phys. Rev. Lett. 89 (2002) 180402] is a good measure of the quantum correlations in a state and provides a new standpoint for understanding quantum non-locality. In this paper, we analytically evaluate the one-way information deficit (OWID) for the Bell-diagonal states and a class of two-qubit states and further give the geometry picture for OWID. The dynamic behavior of the OWID under decoherence channel is investigated and it is shown that the OWID of some classes of X states is more robust against the decoherence than the entanglement. (general)
Definition and evolution of quantum cellular automata with two qubits per cell
International Nuclear Information System (INIS)
Karafyllidis, Ioannis G.
2004-01-01
Studies of quantum computer implementations suggest cellular quantum computer architectures. These architectures can simulate the evolution of quantum cellular automata, which can possibly simulate both quantum and classical physical systems and processes. It is however known that except for the trivial case, unitary evolution of one-dimensional homogeneous quantum cellular automata with one qubit per cell is not possible. Quantum cellular automata that comprise two qubits per cell are defined and their evolution is studied using a quantum computer simulator. The evolution is unitary and its linearity manifests itself as a periodic structure in the probability distribution patterns
International Nuclear Information System (INIS)
Bai Yankui; Li Shushen; Zheng Houzhi
2005-01-01
We present a parametrically efficient method for measuring the entanglement of formation E f in an arbitrarily given unknown two-qubit state ρ AB by local operations and classical communication. The two observers, Alice and Bob, first perform some local operations on their composite systems separately, by which the desired global quantum states can be prepared. Then they estimate seven functions via two modified local quantum networks supplemented a classical communication. After obtaining these functions, Alice and Bob can determine the concurrence C and the entanglement of formation E f
Efficient one- and two-qubit pulsed gates for an oscillator-stabilized Josephson qubit
International Nuclear Information System (INIS)
Brito, Frederico; DiVincenzo, David P; Koch, Roger H; Steffen, Matthias
2008-01-01
We present theoretical schemes for performing high-fidelity one- and two-qubit pulsed gates for a superconducting flux qubit. The 'IBM qubit' consists of three Josephson junctions, three loops and a superconducting transmission line. Assuming a fixed inductive qubit-qubit coupling, we show that the effective qubit-qubit interaction is tunable by changing the applied fluxes, and can be made negligible, allowing one to perform high-fidelity single qubit gates. Our schemes are tailored to alleviate errors due to 1/f noise; we find gates with only 1% loss of fidelity due to this source, for pulse times in the range of 20-30 ns for one-qubit gates (Z rotations, Hadamard) and 60 ns for a two-qubit gate (controlled-Z). Our relaxation and dephasing time estimates indicate a comparable loss of fidelity from this source. The control of leakage plays an important role in the design of our shaped pulses, preventing shorter pulse times. However, we have found that imprecision in the control of the quantum phase plays a major role in the limitation of the fidelity of our gates
Effect of noise on deterministic joint remote preparation of an arbitrary two-qubit state
Wang, Ming-Ming; Qu, Zhi-Guo; Wang, Wei; Chen, Jin-Guang
2017-05-01
Quantum communication has attracted much attention in recent years. Deterministic joint remote state preparation (DJRSP) is an important branch of quantum secure communication which could securely transmit a quantum state with 100% success probability. In this paper, we study DJRSP of an arbitrary two-qubit state in noisy environment. Taking a GHZ based DJRSP scheme of a two-qubit state as an example, we study how the scheme is influenced by all types of noise usually encountered in real-world implementations of quantum communication protocols, i.e., the bit-flip, phase-flip (phase-damping), depolarizing, and amplitude-damping noise. We demonstrate that there are four different output states in the amplitude-damping noise, while there is the same output state in each of the other three types of noise. The state-independent average fidelity is presented to measure the effect of noise, and it is shown that the depolarizing noise has the worst effect on the DJRSP scheme, while the amplitude-damping noise or the phase-flip has the slightest effect depending on the noise rate. Our results are also suitable for JRSP and RSP.
Demonstration of two-qubit algorithms with a superconducting quantum processor.
DiCarlo, L; Chow, J M; Gambetta, J M; Bishop, Lev S; Johnson, B R; Schuster, D I; Majer, J; Blais, A; Frunzio, L; Girvin, S M; Schoelkopf, R J
2009-07-09
Quantum computers, which harness the superposition and entanglement of physical states, could outperform their classical counterparts in solving problems with technological impact-such as factoring large numbers and searching databases. A quantum processor executes algorithms by applying a programmable sequence of gates to an initialized register of qubits, which coherently evolves into a final state containing the result of the computation. Building a quantum processor is challenging because of the need to meet simultaneously requirements that are in conflict: state preparation, long coherence times, universal gate operations and qubit readout. Processors based on a few qubits have been demonstrated using nuclear magnetic resonance, cold ion trap and optical systems, but a solid-state realization has remained an outstanding challenge. Here we demonstrate a two-qubit superconducting processor and the implementation of the Grover search and Deutsch-Jozsa quantum algorithms. We use a two-qubit interaction, tunable in strength by two orders of magnitude on nanosecond timescales, which is mediated by a cavity bus in a circuit quantum electrodynamics architecture. This interaction allows the generation of highly entangled states with concurrence up to 94 per cent. Although this processor constitutes an important step in quantum computing with integrated circuits, continuing efforts to increase qubit coherence times, gate performance and register size will be required to fulfil the promise of a scalable technology.
Pattern Classifications Using Grover's and Ventura's Algorithms in a Two-qubits System
Singh, Manu Pratap; Radhey, Kishori; Rajput, B. S.
2018-03-01
Carrying out the classification of patterns in a two-qubit system by separately using Grover's and Ventura's algorithms on different possible superposition, it has been shown that the exclusion superposition and the phase-invariance superposition are the most suitable search states obtained from two-pattern start-states and one-pattern start-states, respectively, for the simultaneous classifications of patterns. The higher effectiveness of Grover's algorithm for large search states has been verified but the higher effectiveness of Ventura's algorithm for smaller data base has been contradicted in two-qubit systems and it has been demonstrated that the unknown patterns (not present in the concerned data-base) are classified more efficiently than the known ones (present in the data-base) in both the algorithms. It has also been demonstrated that different states of Singh-Rajput MES obtained from the corresponding self-single- pattern start states are the most suitable search states for the classification of patterns |00>,|01 >, |10> and |11> respectively on the second iteration of Grover's method or the first operation of Ventura's algorithm.
Multihop teleportation of two-qubit state via the composite GHZ–Bell channel
Energy Technology Data Exchange (ETDEWEB)
Zou, Zhen-Zhen [State Key Lab. of Millimeter Waves, Southeast University, Nanjing, 210096 (China); Yu, Xu-Tao, E-mail: yuxutao@seu.edu.cn [State Key Lab. of Millimeter Waves, Southeast University, Nanjing, 210096 (China); Gong, Yan-Xiao [Department of Physics, Southeast University, Nanjing, 211189 (China); Zhang, Zai-Chen [National Mobile Communications Research Lab, Southeast University, Nanjing, 210096 (China)
2017-01-15
A multihop teleportation protocol in quantum communication network is introduced to teleport an arbitrary two-qubit state, between two nodes without directly sharing entanglement pairs. Quantum channels are built among neighbor nodes based on a five-qubit entangled system composed of GHZ and Bell pairs. The von Neumann measurements in all intermediate nodes and the source node are implemented, and then the measurement outcomes are sent to the destination node independently. After collecting all the measurement outcomes at the destination node, an efficient method is proposed to calculate the unitary operations for transforming the receiver's states to the state teleported. Therefore, only adopting the proper unitary operations at the destination node, the desired quantum state can be recovered perfectly. The transmission flexibility and efficiency of quantum network with composite GHZ–Bell channel are improved by transmitting measurement outcomes of all nodes in parallelism and reducing hop-by-hop teleportation delay. - Highlights: • A multihop teleportation protocol is introduced to teleport two-qubit state. • Quantum channels are built by composite of GHZ and Bell pairs. • Measurement outcomes are sent to the destination node independently. • Destination node calculates and adopts unitary operations to recover initial state.
Remark on Heisenberg's principle
International Nuclear Information System (INIS)
Noguez, G.
1988-01-01
Application of Heisenberg's principle to inertial frame transformations allows a distinction between three commutative groups of reciprocal transformations along one direction: Galilean transformations, dual transformations, and Lorentz transformations. These are three conjugate groups and for a given direction, the related commutators are all proportional to one single conjugation transformation which compensates for uniform and rectilinear motions. The three transformation groups correspond to three complementary ways of measuring space-time as a whole. Heisenberg's Principle then gets another explanation [fr
Coherence evolution in two-qubit system going through amplitude damping channel
Zhao, MingJing; Ma, Teng; Ma, YuQuan
2018-02-01
In this paper, we analyze the evolution of quantum coherence in a two-qubit system going through the amplitude damping channel. After they have gone through this channel many times, we analyze the systems with respect to the coherence of their output states. When only one subsystem goes through the channel, frozen coherence occurs if and only if this subsystem is incoherent and an auxiliary condition is satisfied for the other subsystem. When two subsystems go through this quantum channel, quantum coherence can be frozen if and only if the two subsystems are both incoherent. We also investigate the evolution of coherence for maximally incoherent-coherent states and derive an equation for the output states after one or two subsystems have gone through the amplitude damping channel.
Dynamically correcting two-qubit gates against any systematic logical error
Calderon Vargas, Fernando Antonio
The reliability of quantum information processing depends on the ability to deal with noise and error in an efficient way. A significant source of error in many settings is coherent, systematic gate error. This work introduces a set of composite pulse sequences that generate maximally entangling gates and correct all systematic errors within the logical subspace to arbitrary order. These sequences are applica- ble for any two-qubit interaction Hamiltonian, and make no assumptions about the underlying noise mechanism except that it is constant on the timescale of the opera- tion. The prime use for our results will be in cases where one has limited knowledge of the underlying physical noise and control mechanisms, highly constrained control, or both. In particular, we apply these composite pulse sequences to the quantum system formed by two capacitively coupled singlet-triplet qubits, which is charac- terized by having constrained control and noise sources that are low frequency and of a non-Markovian nature.
Quantum coherence of two-qubit over quantum channels with memory
Guo, You-neng; Tian, Qing-long; Zeng, Ke; Li, Zheng-da
2017-12-01
Using the axiomatic definition of the quantum coherence measure, such as the l1 norm and the relative entropy, we study the phenomena of two-qubit system quantum coherence through quantum channels where successive uses of the channels are memory. Different types of noisy channels with memory, such as amplitude damping, phase damping, and depolarizing channels effect on quantum coherence have been discussed in detail. The results show that quantum channels with memory can efficiently protect coherence from noisy channels. Particularly, as channels with perfect memory, quantum coherence is unaffected by the phase damping as well as depolarizing channels. Besides, we also investigate the cohering and decohering power of quantum channels with memory.
Entanglement routers via a wireless quantum network based on arbitrary two qubit systems
International Nuclear Information System (INIS)
Metwally, N
2014-01-01
A wireless quantum network is generated between multi-hops, where each hop consists of two entangled nodes. These nodes share a finite number of entangled two-qubit systems randomly. Different types of wireless quantum bridges (WQBS) are generated between the non-connected nodes. The efficiency of these WQBS to be used as quantum channels between its terminals to perform quantum teleportation is investigated. We suggest a theoretical wireless quantum communication protocol to teleport unknown quantum signals from one node to another, where the more powerful WQBS are used as quantum channels. It is shown that, by increasing the efficiency of the sources that emit the initial partial entangled states, one can increase the efficiency of the wireless quantum communication protocol. (paper)
Sufficient criterion for guaranteeing that a two-qubit state is unsteerable
Bowles, Joseph; Hirsch, Flavien; Quintino, Marco Túlio; Brunner, Nicolas
2016-02-01
Quantum steering can be detected via the violation of steering inequalities, which provide sufficient conditions for the steerability of quantum states. Here we discuss the converse problem, namely, ensuring that an entangled state is unsteerable and hence Bell local. We present a simple criterion, applicable to any two-qubit state, that guarantees that the state admits a local hidden state model for arbitrary projective measurements. Specifically, we construct local hidden state models for a large class of entangled states, which thus cannot violate any steering or Bell inequality. In turn, this leads to sufficient conditions for a state to be only one-way steerable and provides the simplest possible example of one-way steering. Finally, by exploiting the connection between steering and measurement incompatibility, we give a sufficient criterion for a continuous set of qubit measurements to be jointly measurable.
A comparative study of the P and Q representations of a feedback controlled two-qubit system
Wang, Jin
2011-05-01
In this Letter the Master equation of a two qubit system is transformed into Fokker-Planck equations in order to find the Glauber-Sudarshan P function representation. For the two qubit system examined in this Letter, the P representation is ill defined, which indicates the system is non-classical. A qualitative measure of the non-classical nature of the system is found by taking the semi-classical limit of the Fokker-Planck equation and obtaining a simplified Glauber-Sudarshan P representation. The agreement between the simplified P representation and the Q representation as well as the system stability are discussed when feedback is present and absent.
Strategy Development of PT XYZ a Startup Technology Company
Rahman, Leila Fatmasari; Mangkusubroto, Kuntoro; Sunitiyoso, Yos
2012-01-01
PT. XYZ (XYZ) is an Indonesian startup technology company which provides IT Consulting and System Integration services. In this research, XYZ's strategy for the next three years (until 2015) will be crafted by going through the strategic management process which consists of the following stages: (1) environment analysis of XYZ, (2) setting strategic vision, (3) setting objective, (4) crafting strategy and (5) executing the strategy. Based on the result of the environment analysis, XYZ's visio...
Wang, Xin; Miranowicz, Adam; Li, Hong-Rong; Nori, Franco
2017-12-01
The coherent process that a single photon simultaneously excites two qubits has recently been theoretically predicted by Garziano et al. [L. Garziano, V. Macrì, R. Stassi, O. Di Stefano, F. Nori, and S. Savasta, One Photon Can Simultaneously Excite two or More Atoms, Phys. Rev. Lett. 117, 043601 (2016), 10.1103/PhysRevLett.117.043601]. We propose a different approach to observe a similar dynamical process based on a superconducting quantum circuit, where two coupled flux qubits longitudinally interact with the same resonator. We show that this simultaneous excitation of two qubits (assuming that the sum of their transition frequencies is close to the cavity frequency) is related to the counter-rotating terms in the dipole-dipole coupling between two qubits, and the standard rotating-wave approximation is not valid here. By numerically simulating the adiabatic Landau-Zener transition and Rabi-oscillation effects, we clearly verify that the energy of a single photon can excite two qubits via higher-order transitions induced by the longitudinal couplings and the counter-rotating terms. Compared with previous studies, the coherent dynamics in our system only involves one intermediate state and, thus, exhibits a much faster rate. We also find transition paths which can interfere. Finally, by discussing how to control the two longitudinal-coupling strengths, we find a method to observe both constructive and destructive interference phenomena in our system.
International Nuclear Information System (INIS)
Alves de Brito, Wellington; Viana Ramos, Rubens
2006-01-01
In this work, we analyze the loss of entanglement of bipartite states after propagation in a noisy channel modeled by the interaction between the bipartite state and the environment through a canonical unitary form of a two-qubit gate. An analytic expression for the entanglement loss is found
Indian Academy of Sciences (India)
Home; Fellowship. Fellow Profile. Elected: 1935 Honorary. Heisenberg, Prof. Werner Karl Nobel Laureate (Physics) - 1932. Date of birth: 5 December 1901. Date of death: 1 February 1976. YouTube; Twitter; Facebook; Blog. Academy News. IAS Logo. 29th Mid-year meeting. Posted on 19 January 2018. The 29th Mid-year ...
Indian Academy of Sciences (India)
Home; Fellowship. Fellow Profile. Elected: 1935 Honorary. Heisenberg, Prof. Werner Karl Nobel Laureate (Physics) - 1932. Date of birth: 5 December 1901. Date of death: 1 February 1976. YouTube; Twitter; Facebook; Blog. Academy News. IAS Logo. Theory Of Evolution. Posted on 23 January 2018. Joint Statement by the ...
Generation of concurrence between two qubits locally coupled to a one-dimensional spin chain
Nag, Tanay; Dutta, Amit
2016-08-01
We consider a generalized central spin model, consisting of two central qubits and an environmental spin chain (with periodic boundary condition) to which these central qubits are locally and weakly connected either at the same site or at two different sites separated by a distance d . Our purpose is to study the subsequent temporal generation of entanglement, quantified by concurrence, when initially the qubits are in an unentangled state. In the equilibrium situation, we show that the concurrence survives for a larger value of d when the environmental spin chain is critical. Importantly, a common feature observed both in the equilibrium and the nonequilibrium situations while the latter is created by a sudden but global change of the environmental transverse field is that the two qubits become maximally entangled for the critical quenching. Following a nonequilibrium evolution of the spin chain, our study for d ≠0 indicates that there exists a threshold time above which concurrence attains a finite value. Additionally, we show that the number of independent decohering channels (DCs) is determined by d as well as the local difference of the transverse field of the two underlying Hamiltonians governing the time evolution; the concurrence can be enhanced by a higher number of independent channels. The qualitatively similar behavior displayed by the concurrence for critical and off-critical quenches, as reported here, is characterized by analyzing the nonequilibrium evolution of these channels. The concurrence is maximum when the decoherence factor or the echo associated with the most rapidly DC decays to zero; on the contrary, the condition when the concurrence vanishes is determined nontrivially by the associated decay of one of the intermediate DCs. Analyzing the reduced density of a single qubit, we also explain the observation that the dephasing rate is always slower than the unentanglement rate. We further establish that the maximally and minimally decohering
Quantum discord for a central two-qubit system coupled to an XY-spin-chain environment
International Nuclear Information System (INIS)
Liu Benqiong; Shao Bin; Zou Jian
2010-01-01
We investigate the dynamic behaviors of quantum discord for a central two-qubit system coupled to an XY-spin-chain environment. In the weak-coupling regime, we show that the quantum discord for the two central qubits can become minimized rapidly close to the critical point of a quantum phase transition. By considering the two qubits that are initially prepared in the Werner state, we study the evolution of the quantum discord and that of entanglement under the same conditions. Our results imply that entanglement can disappear completely after a finite time, while the quantum discord decreases and tends to be a stable value according to the initial-state parameter for a very-long-time interval. In this sense, the quantum discord is more robust than entanglement for the quantum system exposed to the environment. The relation between the quantum correlations and the classical correlation is also shown for two particular cases.
Decoherence of Two-qubits Coupled with Reservoirs Studied with New Ket-Bra Entangled State Method
Ren, Yi-Chong; Fan, Hong-Yi
2016-04-01
For the first time we define a so-called Ket-Bra Entangled State (KBES) for two-qubits coupled with reservoirs by introduce an extra fictitious mode vector, and convert the corresponding master equation into Schrödinger-like equation by virtue of this state. Via this approach we concisely obtain the dynamic evolution of two uncoupled qubits each immersed in local thermal noise. Based on this, the decoherence evolution for the extended Werner-like states is derived and how purity and temperature influence the concurrence is analyzed. This KBES method may also be applied to tackling master equations of limited atomic level systems.
Recent results on XYZ States at Belle
Shen, Chengping
2016-05-01
Exotic hadronic states beyond the conventional quark model (called charmoniumlike/bottomoniumlike states or XYZ particles) have been sought and many candidates were proposed including glueballs, hybrids, multi-quark states, hadron molecules, etc. Dramatic progress has been made in the study of such exotic hadrons after the running of the B-factories. In this report, I present the most recent results on the XYZ states at Belle, including (1) X states: the first observation of B0 → X(3872)K+π- and evidence for B+ → X(3872)K0 π+; search for the Xb state; (2) Y states: the updated results for the Y(4360) and Y(4660) and cross section measurement of e+e- → K+ K- J/ψ; (3) Z states: the evidence for the Zc(4050)± → π±ψ(2S); search for the Zcs in e+e- → K+ K- J/ψ.
Directory of Open Access Journals (Sweden)
Ynduráin, Francisco J.
2002-01-01
Full Text Available Not available
Los azares de las onomásticas hacen coincidir en este año el centenario del nacimiento de tres de los más grandes físicos del siglo XX. Dos de ellos, Fermi y Heisenberg, dejaron una marca fundamental en la ciencia (ambos, pero sobre todo el segundo y, el primero, también en la tecnología. Lawrence, indudablemente de un nivel inferior al de los otros dos, estuvo sin embargo en el origen de uno de los desarrollos tecnológicos que han sido básicos para la exploración del universo subnuclear en la segunda mitad del siglo que ha terminado hace poco, el de los aceleradores de partículas.
Heisenberg and the Interpretation of Quantum Mechanics
Camilleri, Kristian
2011-09-01
Preface; 1. Introduction; Part I. The Emergence of Quantum Mechanics: 2. Quantum mechanics and the principle of observability; 3. The problem of interpretation; Part II. The Heisenberg-Bohr Dialogue: 4. The wave-particle duality; 5. Indeterminacy and the limits of classical concepts: the turning point in Heisenberg's thought; 6. Heisenberg and Bohr: divergent viewpoints of complementarity; Part III. Heisenberg's Epistemology and Ontology of Quantum Mechanics: 7. The transformation of Kantian philosophy; 8. The linguistic turn in Heisenberg's thought; Conclusion; References; Index.
Giorda, Paolo; Allegra, Michele
2017-07-01
Understanding how correlations can be used for quantum communication protocols is a central goal of quantum information science. While many authors have linked the global measures of correlations such as entanglement or discord to the performance of specific protocols, in general the latter may require only correlations between specific observables. In this work, we first introduce a general measure of correlations for two-qubit states, based on the classical mutual information between local observables. Our measure depends on the state’s purity and the symmetry in the correlation distribution, according to which we provide a classification of maximally mixed marginal states (MMMS). We discuss the complementarity relation between correlations and coherence. By focusing on a simple yet paradigmatic example, i.e. the remote state preparation protocol, we introduce a method to systematically define the proper protocol-tailored measures of the correlations. The method is based on the identification of those correlations that are relevant (useful) for the protocol. On the one hand, the approach allows the role of the symmetry of the correlation distribution to be discussed in determining the efficiency of the protocol, both for MMMS and general two-qubit quantum states, and on the other hand, it allows an optimized protocol for non-MMMS to be devised, which is more efficient with respect to the standard one. Overall, our findings clarify how the key resources in simple communication protocols are the purity of the state used and the symmetry of the correlation distribution.
Intramuscular Gluteal Augmentation: The XYZ Method.
Gonzalez, Raul; Gonzalez, Ricardo
2018-04-01
Although interest in buttocks implant procedures is growing around the world, it remains a technically demanding procedure. The intramuscular plane is thought to be superior to other planes of dissection. Asymmetry and visibility of the implants remain frequent complications when the surgeon works without any reference points to guide the procedure. The XYZ method helps the surgeon to obtain symmetry, to significantly reduce implant visibility and to decrease other complications associated with buttocks implants. The method uses the surface anatomy of the boney frame of the pelvis to perform a geometric plane to detach the muscle. Published by Elsevier Inc.
Optimising polarised neutron scattering measurements--XYZ and polarimetry analysis
International Nuclear Information System (INIS)
Cussen, L.D.; Goossens, D.J.
2002-01-01
The analytic optimisation of neutron scattering measurements made using XYZ polarisation analysis and neutron polarimetry techniques is discussed. Expressions for the 'quality factor' and the optimum division of counting time for the XYZ technique are presented. For neutron polarimetry the optimisation is identified as analogous to that for measuring the flipping ratio and reference is made to the results already in the literature
Optimising polarised neutron scattering measurements--XYZ and polarimetry analysis
Cussen, L D
2002-01-01
The analytic optimisation of neutron scattering measurements made using XYZ polarisation analysis and neutron polarimetry techniques is discussed. Expressions for the 'quality factor' and the optimum division of counting time for the XYZ technique are presented. For neutron polarimetry the optimisation is identified as analogous to that for measuring the flipping ratio and reference is made to the results already in the literature.
Berry phase in Heisenberg representation
Andreev, V. A.; Klimov, Andrei B.; Lerner, Peter B.
1994-01-01
We define the Berry phase for the Heisenberg operators. This definition is motivated by the calculation of the phase shifts by different techniques. These techniques are: the solution of the Heisenberg equations of motion, the solution of the Schrodinger equation in coherent-state representation, and the direct computation of the evolution operator. Our definition of the Berry phase in the Heisenberg representation is consistent with the underlying supersymmetry of the model in the following sense. The structural blocks of the Hamiltonians of supersymmetrical quantum mechanics ('superpairs') are connected by transformations which conserve the similarity in structure of the energy levels of superpairs. These transformations include transformation of phase of the creation-annihilation operators, which are generated by adiabatic cyclic evolution of the parameters of the system.
Heisenberg, his wife s account
International Nuclear Information System (INIS)
Heisenberg, E.
1990-01-01
A wife tells about her husband life, Werner Heisenberg, Physics Nobel Price in 1932. After a happy childhood, this brilliant student was Albert Einstein, Niels Bohr, Arnold Sommerfeld s student. But at the nazism time, the great physician refused to leave his country, guaranteeing the Hitler regime and taking part in effort of war, that is to say the run to the bomb. The account of Elisabeth Heisenberg, although subjective, allows to understand the scientist s behaviour face terrifying realities of his time. (N.C.)
Chomology of Heisenberg Hom-Lie algebras
Nejib, Saadaoui
2017-01-01
In this paper, we define the Heisenberg Hom-Lie algebra. We determine the minimal dimension of faithful representation for Heisenberg Hom-Lie algebra.We study the adjoint representation, the trivial representation and the faithful representation of Heisenberg Hom-Lie algebra.
Energy Technology Data Exchange (ETDEWEB)
Dong, Li; Xiu, Xiao-Ming, E-mail: xiuxiaomingdl@126.com [Dalian University of Technology, School of Physics and Optoelectronic Technology (China); Ren, Yuan-Peng [Bohai University, Higher Professional Technical Institute (China); Gao, Ya-Jun [Bohai University, College of Mathematics and Physics (China); Yi, X. X. [Dalian University of Technology, School of Physics and Optoelectronic Technology (China)
2013-01-15
We propose a protocol transferring an arbitrary unknown two-qubit state using the quantum channel of a four-qubit genuine entangled state. Simplifying the four-qubit joint measurement to the combination of Bell-state measurements, it can be realized more easily with currently available technologies.
Werner Heisenberg - Life and Work
2002-01-01
Werner Heisenberg (centre) with Wolfgang Pauli and Enrico Fermi, 1927. An exhibition on the life and work of Werner Heisenberg will be on display in the Main Building (Mezzanine) at CERN from 1 - 30 July*. German theoretical physicist Werner Karl Heisenberg (1901 - 1976) was one of the leading scientists of the 20th century. Nobel Prize in Physics in 1932, his most significant contribution was to the development of quantum mechanics. He is best known for his uncertainty principle, which restricts the accuracy with which some properties of atoms and particles can be determined simultaneously. Heisenberg was a keen supporter of CERN, and was as the first chairman of CERN's Scientific Policy Committee in October 1954. A related celebration will take place in the TH Amphitheatre (4/3-006), on Thursday 18 July at 16:00. After an introduction from the Director-General Luciano Maiani, his daughter, Barbara Blum, his last postgraduate, Helmut Rechenberg and Valentin Telegdi will evoke memories of the life and work ...
Non-Hermitian Heisenberg representation
Czech Academy of Sciences Publication Activity Database
Znojil, Miloslav
2015-01-01
Roč. 379, č. 36 (2015), s. 2013-2017 ISSN 0375-9601 Institutional support: RVO:61389005 Keywords : quantum mechanics * Non-Hermitian representation of observables * Generalized Heisenberg equations Subject RIV: BE - Theoretical Physics Impact factor: 1.677, year: 2015
Werner Heisenberg - Life and Work
2002-01-01
Werner Heisenberg (centre) with Wolfgang Pauli (left) and Enrico Fermi on Lake Como, September 1927. An exhibition on the life and work of Werner Heisenberg will be on display in the Main Building (Mezzanine) at CERN from 1 - 23 July. The exhibition was produced by the University Archive of Leipzig University (Gerald Wiemers) and the Max-Planck-Institut für Physik in Munich (Helmut Rechenberg) to mark the centenary of Heisenberg's birth in 1901. German theoretical physicist Werner Karl Heisenberg (5 December 1901 - 1 February 1976) was one of the leading scientists of the 20th century. He carried out important work in nuclear and particle physics, but his most significant contribution was to the development of quantum mechanics. He is best known for his uncertainty principle, which restricts the accuracy with which some properties of atoms and particles - such as position and linear momentum - can be determined simultaneously. In 1932 he was awarded the Noble Prize in Physics 'for the creation of q...
Pengaruh Customer Perceived Value Terhadap Customer Satisfaction PT. Xyz
Sucahyo, Martinus Wilman
2017-01-01
Penelitian ini membahas tentang Customer Perceived Value terhadap Customer Satisfaction PT. XYZ. Dalam penelitian ini, Customer Perceived Value diukur melalui dimensi Core Product Value, Service Value dan Relationship Value. Masing-masing dimensi ini akan diuji pengaruhnya terhadap Customer Satisfaction, baik secara simultan maupun secara parsial, serta dimensi mana yang paling berpengaruh terhadap Customer Satisfaction. Sampel penelitian berjumlah 100 pelanggan PT. XYZ. Data penelitian diola...
Heisenberg picture and measurement operation
International Nuclear Information System (INIS)
D'Espagnat, B.
1992-01-01
The idea is discussed according to which, in the Heisenberg picture, differently from the Schroedinger picture, the operators correspond exactly to the dynamic properties and the role of the density matrix is merely to describe our passive knowledge thereof. It is shown that the idea in question cannot be consistently kept as it is, and hints are given as to how it could be refined. (from author). 2 refs
Aplikasi Pemasaran Berbasis Web Pt Xyz
Directory of Open Access Journals (Sweden)
Henny Hendarti
2013-12-01
Full Text Available Marketing plays an important role in determining the success of a company's sales. Marketing of goods or services over the Internet opens an opportunity for a company to expand the business into new markets, and compete with other businesses in the same field. It is because the internet offers wider selection of good products, service products, and prices. Thus, customers can be sure in choosing and buying of goods and services. For that e-marketing is introduced as an marketing strategy that integrates internet and marketing. A study was conducted to develop e-marketing application for PT XYZ as a company that produces and sells men’s apparel and accessories. The methodology used in developing the e-marketing application is library research, field research, and a seven-stage approach to build e-marketing. The e-marketing strategy developed is expected to expand market share and increase sales. Additionally, it is expected to be a powerful strategy to build relationships with customers, providing information of both company and its products.
Porcelain Product Quality Analysis in PT XYZ
Directory of Open Access Journals (Sweden)
Ho Hwi Chie
2015-12-01
Full Text Available PT. XYZ is a company engaged in manufacturing porcelain dinner ware such as plates, cups, teapot, bowl, etc Porcelain product is safe for use and product defect will only affect the aesthetic not the functional side. The company always maintain the quality of the products produced as by maintaining a good product, in terms of visuals, will keep customers interested in the product. Good quality products characterized by quality A / B and C, and the product defect characterized by the quality of D, Lost, and BU. Concepts and methods used to analyze is a statistical process control (SPC which includes Pareto diagram, fraction nonconformities, flow charts and fishbone diagrams and management tools (fault tree analysis. Statistical Process Control (SPC is one of the methods, which includes Pareto charts, fraction nonconformities, flow chart, and fishbone diagram and also management tools (fault tree analysis. SPC is useful to find the facts from the problems and factors that affect the quality of the products, while fault tree analysis is useful to analyze each of the production process.
Ming, Fei; Wang, Dong; Shi, Wei-Nan; Huang, Ai-Jun; Sun, Wen-Yang; Ye, Liu
2018-04-01
The uncertainty principle is recognized as an elementary ingredient of quantum theory and sets up a significant bound to predict outcome of measurement for a couple of incompatible observables. In this work, we develop dynamical features of quantum memory-assisted entropic uncertainty relations (QMA-EUR) in a two-qubit Heisenberg XXZ spin chain with an inhomogeneous magnetic field. We specifically derive the dynamical evolutions of the entropic uncertainty with respect to the measurement in the Heisenberg XXZ model when spin A is initially correlated with quantum memory B. It has been found that the larger coupling strength J of the ferromagnetism ( J 0 ) chains can effectively degrade the measuring uncertainty. Besides, it turns out that the higher temperature can induce the inflation of the uncertainty because the thermal entanglement becomes relatively weak in this scenario, and there exists a distinct dynamical behavior of the uncertainty when an inhomogeneous magnetic field emerges. With the growing magnetic field | B | , the variation of the entropic uncertainty will be non-monotonic. Meanwhile, we compare several different optimized bounds existing with the initial bound proposed by Berta et al. and consequently conclude Adabi et al.'s result is optimal. Moreover, we also investigate the mixedness of the system of interest, dramatically associated with the uncertainty. Remarkably, we put forward a possible physical interpretation to explain the evolutionary phenomenon of the uncertainty. Finally, we take advantage of a local filtering operation to steer the magnitude of the uncertainty. Therefore, our explorations may shed light on the entropic uncertainty under the Heisenberg XXZ model and hence be of importance to quantum precision measurement over solid state-based quantum information processing.
Frayn's "Heisenberg": Fact or Fiction? 9 -O ...
Indian Academy of Sciences (India)
2002-03-02
Mar 2, 2002 ... what I know of Werner Heisenberg and how it may relate to his Copenhagen visit. For me Werner Heisenberg was primarily my father. He was a good father, a warm, caring, and compassionate human being who taught us his love for the outdoors, for mountain climbing, music or the spiritual which he ...
Deformation quantization of the Heisenberg group
International Nuclear Information System (INIS)
Bonechi, F.
1994-01-01
After reviewing the way the quantization of Poisson Lie Groups naturally leads to Quantum Groups, the existing quantum version H(1) q of the Heisenberg algebra is used to give an explicit example of this quantization on the Heisenberg group. (author) 6 refs
Crafting New Business Strategy in Indonesia's Fertilizer Company ( Case Study in PT XYZ)
Faswara, Lufan Nassya; Toha, Mohamad
2012-01-01
Fertilizer is the important product in Indonesia. The growth of Indonesia's is highly depending on the supply of fertilizer. PT XYZ is one of the national fertilizer company in Indonesia. PT XYZ is a subsidiary company of a State Owned Enterprise (BUMN) in Indonesia which engaged in fertilizer production and distribution. PT XYZ is the first fertilizer company in Indonesia with objectives to supply fertilizer products to Indonesian farmers. This time, PT XYZ is facing problems in achieving it...
Sarkar, Sujit
2013-04-01
We study the entanglement of a two-qubit system in a superconducting quantum dot (SQD) lattice in the presence of magnetic flux and gate voltage. The ground state is always in a maximally entangled Bell state for homogeneous gate voltage. In the presence of inhomogeneous gate voltage, the half-integer magnetic flux quantum, completely washes out the entanglement of the system at zero temperature. The entanglement is much higher for the Mott insulating phase. At finite temperature, collapse of entanglement occurs for wider region of magnetic flux.
Yang, Chen Ning
2013-05-01
Werner Heisenberg was one of the greatest physicists of all times. When he started out as a young research worker, the world of physics was in a very confused and frustrating state, which Abraham Pais has described1 as: It was the spring of hope, it was the winter of despair using Charles Dickens' words in A Tale of Two Cities. People were playing a guessing game: There were from time to time great triumphs in proposing, through sheer intuition, make-shift schemes that amazingly explained some regularities in spectral physics, leading to joy. But invariably such successes would be followed by further work which reveal the inconsistency or inadequacy of the new scheme, leading to despair...
STRATEGI PENGEMBANGAN KEMITRAAN TERNAK AYAM BROILER PT. XYZ
Directory of Open Access Journals (Sweden)
Latifa Hanum
2011-11-01
Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} The objectives of this research are to (1 analyze profit and BEP of plasma farmers (2 analyze internal and external strategic factors that influence development of broiler partnership in PT. XYZ, (3 formulate the alternative strategies of broiler partnership in PT. XYZ, (4 formulate selected priority strategy to develop broiler partnership in PT. XYZ. This research uses descriptive method based on case study on broiler partnership in PT. XYZ. Based on BEP analysis, BEP (production of plasma farmers is in the range 79,91%-86,58% from chick-in capacity, and BEP (price is in the range of Rp 11.684 – Rp 12.191 per chicken on market price. PT. XYZ partnership’s position in IE matric was second quadrant (grow and builds. The results of SWOT analysis are: a vertical integration strategy through feedmill, breeding and chicken slaughterhouse, b improving production capacity through capacity building of plasma farmers, c improvement in bio-security aspects of maintenance, and d improving the quality of technical staff and improving supervision. The priority strategy from QSPM analysis is improving production capacity through capacity building of plasma farmers. The strategy to improve production capacity can be done by maximize or add their capacity, and add the new plasma farmers. Keywords: Broiler Partnership, Internal Environment, External Environment, Internal-external, Improvement Priority
Directory of Open Access Journals (Sweden)
Mohammed Daoud
2018-04-01
Full Text Available A relation is established in the present paper between Dicke states in a d-dimensional space and vectors in the representation space of a generalized Weyl–Heisenberg algebra of finite dimension d. This provides a natural way to deal with the separable and entangled states of a system of N = d − 1 symmetric qubit states. Using the decomposition property of Dicke states, it is shown that the separable states coincide with the Perelomov coherent states associated with the generalized Weyl–Heisenberg algebra considered in this paper. In the so-called Majorana scheme, the qudit (d-level states are represented by N points on the Bloch sphere; roughly speaking, it can be said that a qudit (in a d-dimensional space is describable by a N-qubit vector (in a N-dimensional space. In such a scheme, the permanent of the matrix describing the overlap between the N qubits makes it possible to measure the entanglement between the N qubits forming the qudit. This is confirmed by a Fubini–Study metric analysis. A new parameter, proportional to the permanent and called perma-concurrence, is introduced for characterizing the entanglement of a symmetric qudit arising from N qubits. For d = 3 ( ⇔ N = 2 , this parameter constitutes an alternative to the concurrence for two qubits. Other examples are given for d = 4 and 5. A connection between Majorana stars and zeros of a Bargmmann function for qudits closes this article.
Two dimensional compass model with Heisenberg interactions
Pires, A. S. T.
2018-04-01
We consider a two dimensional compass model with a next and a next near Heisenberg term. The interactions are of two types: frustrated near neighbor compass interactions of amplitudes Jx and Jy, and next and next near neighbor Heisenberg interactions with exchanges J1 and J2 respectively. The Heisenberg interactions are isotropic in spin space, but the compass interactions depend on the bond direction. The ground state of the pure compass model is degenerated with a complex phase diagram. This degeneracy is removed by the Heisenberg terms leading to the arising of a magnetically ordered phase with a preferred direction. We calculate the phase diagrams at zero temperature for the case where, for J2 = 0, we have an antiferromagnetic ground state. We show that varying the value of J2, a magnetically disordered phase can be reached for small values of the compass interactions. We also calculate the critical temperature for a specified value of parameters.
STRATEGI PENINGKATAN DAYA SAING RUMAH POTONG AYAM PT XYZ
Directory of Open Access Journals (Sweden)
Arli Arli
2012-07-01
Full Text Available ABSTRACTThe objectives of this study were (1 analyzing the role of parties in the value chain that affect PT XYZ competitiveness, (2 identifying the RPA PT XYZ stakeholders’ key players, (3 analyzing internal and external (IE factors that affects the competitiveness of RPA PT XYZ , (4 formulating strategic long term objectives and goals to increase the competitiveness of RPA PT XYZ , (5 analyzing strategies’ priorities and alternatives to improve the competitiveness of RPA PT XYZ . The method used in this study was descriptive analysis. The analysis tools used in this study were global value chain, stakeholders’ analysis, internal factor evaluation, external factor evaluation, IE Matrix, SWOT, and quantitative strategic planning matrix. Based on the results of global value chain analysis, stakeholders analysis, internal and external analysis, and the company’s visions and missions, the long term objectives are (a to provide value added for customers, (b to maximize business operation’s profit, (c to increase stakeholders’ welfare, (d to operate a sustainable business operation. Results on the IE Matrix and the SWOT analysis, the strategies that can be used to achieve the strategic long term objectives and goals are (a to increase the effectiveness and the efficiencies of the supply chain management; (b to implement performance evaluation on employees and business partners; (c to strengthen the company’s image as a high quality domestic chicken-based food producer in Indonesia; (d to enhance researches and developments; (e to build strategic alliances with external live chicken suppliers; (f promote the importance of animal protein consumption to Indonesian society. Three priority strategies resulted from QSPM analysis are create enhancing the effectiveness and efficiency of the supply chain, implementing performance evaluation on employees and business partners, and strengthen the company’s image as a high quality domestic
Color speckle measurement errors using system with XYZ filters
Kinoshita, Junichi; Yamamoto, Kazuhisa; Kuroda, Kazuo
2018-02-01
Measurement errors of color speckle are analyzed for a measurement system equipped with revolving XYZ filters and a 2D sensor. One of the errors is caused by the filter characteristics unfitted to the ideal color matching functions. The other is caused by uncorrelations among the optical paths via the XYZ filters. The unfitted color speckle errors of all the pixel data can be easily calibrated by conversion between the measured BGR chromaticity triangle and the true triangle obtained by the BGR wavelength measurements. For the uncorrelated errors, the measured BGR chromaticity values spread over around the true values. As a result, it would be more complicated to calibrate the uncorrelated errors, repeating the triangular conversion pixel by pixel. Color speckle and its errors greatly affect also chromaticity measurements and image quality of displays using coherent light sources.
SISTEM INFORMASI MANAJEMEN HUBUNGAN PELANGGAN PADA PT. XYZ PALEMBANG
Directory of Open Access Journals (Sweden)
Fransisca Fransisca
2017-06-01
Full Text Available PT. XYZ is distributor and sales of mobile phone in Palembang city. PT. XYZ is not maximal for giving services to customers where it need more time in purchase order and sale products . There’s no easiness in interaction process between customer and company where company when interacting with customers only by phone and face to face. Information delivery about products, promotions, customers critique and suggestions can not informed quickly. For customer data management by this day can not used and maximized for analysing customers needs and customers purchase behaviors. In the development of this system use Iteration methodology with PHP language programming and MySQL database. The system that is being develop has feature like product order, purchase, critique and suggestions, and live chat that make communication more communicative and interactive. These system also generates customers report, best customers report, transactions report, and best sales product report. The result of this research is a design of customer relationship management system that easier PT. XYZ to manage relationship to customer
Perancangan Sistem Informasi Prepaid di Perusahaan Makanan Siap Saji XYZ
Directory of Open Access Journals (Sweden)
J. Rolles Herwin Sihombing
2015-06-01
Full Text Available Prepaid System becomes a new trend in the Indonesia retail industry, particularly in the Food and Beverage (F&B sector. Many companies are trying to develop their own prepaid system, however they still lack of skills and knowledge regarding this system. This condition might not enable them to deliver the prepaid system to customers properly if they insist to develop their own system. However, this does not happen to company XYZ, the biggest fast food restaurant in Indonesia. Company XYZ, which collaborates with the local partner, implements their own prepaid system in their company. This local partner has already had years of experience in the payment industry, developing payment system that adapts to the latest technology and supports the company's business. A system that is integrated with the point-of-sales and website would absolutely help customer and cashier in doing the transaction process. Integrated data is very useful for the finance and accounting departments of Company XYZ providing annual financial report to the shareholders.
Siregar, Yigal Allon; Toha, Mohamad
2012-01-01
Economic growth will increase competition among companies in industry, and it happen in Bandung area, with current growth in economic and tourism industry also influence competition level in culinary business in Bandung. Bakery XYZ, that already in Bandung since 1991 affected of the current competition in culinary business. Currently Bakery XYZ is facing decreasing sales volume due to increasing competitors. To improve its business performance, is required to analysis Bakery XYZ's business s...
The Heisenberg picture for single photon states
International Nuclear Information System (INIS)
Pienaar, Jacques; Myers, Casey; Ralph, Timothy C.
2011-01-01
In the context of quantum field theory, the Heisenberg picture has a distinct advantage over the Schrodinger picture because the Schrodinger picture requires us to transform the vacuum state itself, which can be intractable in the case of non-inertial reference frames, whereas the Heisenberg picture allows us to keep the same vacuum state and only transform the operators. However, the Heisenberg calculation requires the operators to already be expressed as a function of creation and annihilation operators acting on the original vacuum, whereas calculations in quantum information and quantum computation use operators that act on qubit states, necessarily containing particles. The relationship between the operators acting on these states and the operators acting on the vacuum state has remained elusive. We derive such an expression using an explicit model for single-particle production from the vacuum.
Putra A, Freggy Griyatta; Nasution, Reza Ashari
2012-01-01
The development of the lubricant market in the Asia-Pacific, Africa, Middle East, and South America is an opportunity for PT.XYZ in the future. PT. XYZ wants to improve their brand image through co-branding with the SAS company as one of the local oil company in Spain. The study also analyzes the co-branding strategy through Joint Venture of PT. XYZ with SAS to improve the company's brand image in the International market. The conceptual framework of this research started from the goal of PT....
I grandi della fisica da Platone a Heisenberg
Von Weizsäcker, Carl Friedrich
2002-01-01
Parmenide ; Platone ; Aristotele ; Copernico, Keplero, Galilei ; Galileo Galilei ; Cartesio ; Gottfried Wilhelm Leibniz ; Cartesio, Newton, Leibniz, Kant ; Immanuel Kant ; Johann Wolfgang Goethe ; Robert Meyer ; Albert Einstein ; Niels Bohr ; Paul Adrien Maurice Dirac ; Niels Bohr e Werner Heisenberg, un ricordo del 1932 ; Werner Heisenberg ; Heisenberg, fisico e filosofo ; l'interpretazione filosofica della fisica moderna.
PENGEMBANGAN KAMUS KOMPETENSI KESELAMATAN KERJA DI PT XYZ INDONESIA TBK
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Yudhie Dwi Kristanto
2017-01-01
Full Text Available The occupational health and safety known as K3 (Keselamatan dan kesehatan kerja is one of the main objectives of PT XYZ Indonesia ltd. operation. Currently PT XYZ Indonesia ltd has possessed an occupational safety competent model for the operational area originally from XYZ global. The objectives of the research are to define the role of the Occupational safety and health (OSH department, arrange an appropriate competent model and specify the competent level requirements in each job positions and also formulate a development program for each competency. The research uses DACUM (Developing a Curriculum modified method and refers to AMA (American Management Association competent literature. The result of the research shows that there are nine main competencies in the department of occupational safety. The four competencies in occupational safety cover 1 OHS mission implementation & tactical planning, 2 controls hazards & manages risks, 3 result oriented OHS, and 4 mastering complexity & manages incidents. While the other five competencies are related to leadership competent, they are 1 communication, 2 partnering, 3 influencing, 4 building trust & personal accountability, 5 critical & analytical thinking. The content designed for the competent model are 1 the list of nine main required competencies, 2 the definition of each competency, 3 the level of each competency, 4 the development for each level, 5 the need of the competent level for each job positions. Based on the research, it shows that the DACUM modified method is suitable to formulate the competency needed from the unit. Keywords: competent, occupational safety, human resources, DACUM, AMA AbstrakKeselamatan dan kesehatan kerja, atau yang juga dikenal sebagai K3, merupakan salah satu tujuan utama dalam operasi PT XYZ Indonesia tbk. Saat ini PT XYZ Indonesia tbk telah memiliki model kompetensi keselamatan kerja untuk area operasional yang berasal dari XYZ global. Tujuan
On the diophantine equation $ax^{3} + by + c = xyz$
Subburam, Sivanarayanapandian; Thangadurai, Ravindrananathan
2015-01-01
Consider the diophantine equation $ax^{3} + by + c = xyz$, where $a, b$ and $c$ are positive integers such that $\\gcd(a, c) = 1$ and $c$ is square-free. Let $(x, y, z)$ be a positive integral solution of the equation. In this paper, we shall give an upper bound for $x$,$y$ and $z$ in terms of the given inputs $a$, $b$ and $c$. Also, we apply our results to investigate the divisors of the elements of the sequence $\\{an^{3} + c\\}$ in residue classes.
Analisa Risiko Proyek Pengembangan Software Pada CV. XYZ
Apriatono, Nicolas Adriaan; Wibowo, Adi; Gunawan, Ibnu
2015-01-01
CV.XYZ is a small size company that works on software engineering.The worker in this company is not many, between 5 – 8 people only. The problem in this company is there are no identification of risks that can happen. The examples of the problems are the clients suddenly request some features for their software, no milestone on the project, no data about clients' system and no monitoring on the ongoing projects. These things can hold back the company's performance. Thus, risk analysis is need...
Uncertainty inequalities for the Heisenberg group
Indian Academy of Sciences (India)
where φ is an admissible wavelet and kφ is an appropriate positive constant. For more on the history and the relevance of the uncertainty inequality, we refer the readers to the survey [5], the books [6,8], and the papers [2,10,11]. For the Heisenberg group Hn, Thangavelu [16] proved the following theorem. Theorem 1.1.
Halim, Raymond Nathaniel
2016-01-01
This study aimed to analyze the effect of Relationship Benefits to Relationship Continuity through Relationship Value towards the PT. XYZ's customers . This study will be conducted by distributing questionnaires to 30 respondents who have ever made a purchase from PT. XYZ more than 1 time. Analysis technique used is quantitative analysis technique.
Slater, Paul B.
2018-04-01
We begin by investigating relationships between two forms of Hilbert-Schmidt two-rebit and two-qubit "separability functions"—those recently advanced by Lovas and Andai (J Phys A Math Theor 50(29):295303, 2017), and those earlier presented by Slater (J Phys A 40(47):14279, 2007). In the Lovas-Andai framework, the independent variable ɛ \\in [0,1] is the ratio σ (V) of the singular values of the 2 × 2 matrix V=D_2^{1/2} D_1^{-1/2} formed from the two 2 × 2 diagonal blocks (D_1, D_2) of a 4 × 4 density matrix D= ||ρ _{ij}||. In the Slater setting, the independent variable μ is the diagonal-entry ratio √{ρ _{11} ρ _ {44}/ρ _ {22 ρ _ {33}}}—with, of central importance, μ =ɛ or μ =1/ɛ when both D_1 and D_2 are themselves diagonal. Lovas and Andai established that their two-rebit "separability function" \\tilde{χ }_1 (ɛ ) (≈ ɛ ) yields the previously conjectured Hilbert-Schmidt separability probability of 29/64. We are able, in the Slater framework (using cylindrical algebraic decompositions [CAD] to enforce positivity constraints), to reproduce this result. Further, we newly find its two-qubit, two-quater[nionic]-bit and "two-octo[nionic]-bit" counterparts, \\tilde{χ _2}(ɛ ) =1/3 ɛ ^2 ( 4-ɛ ^2) , \\tilde{χ _4}(ɛ ) =1/35 ɛ ^4 ( 15 ɛ ^4-64 ɛ ^2+84) and \\tilde{χ _8} (ɛ )= 1/1287ɛ ^8 ( 1155 ɛ ^8-7680 ɛ ^6+20160 ɛ ^4-25088 ɛ ^2+12740) . These immediately lead to predictions of Hilbert-Schmidt separability/PPT-probabilities of 8/33, 26/323 and 44482/4091349, in full agreement with those of the "concise formula" (Slater in J Phys A 46:445302, 2013), and, additionally, of a "specialized induced measure" formula. Then, we find a Lovas-Andai "master formula," \\tilde{χ _d}(ɛ )= ɛ ^d Γ (d+1)^3 _3\\tilde{F}_2( -{d/2,d/2,d;d/2+1,3 d/2+1;ɛ ^2) }/{Γ ( d/2+1) ^2}, encompassing both even and odd values of d. Remarkably, we are able to obtain the \\tilde{χ _d}(ɛ ) formulas, d=1,2,4, applicable to full (9-, 15-, 27-) dimensional sets of
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Darmawan Baginda Napitupulu
2016-07-01
Full Text Available Penelitian ini bertujuan untuk mengevaluasi kualitas website Universitas XYZ dengan pendekatan WebQual. WebQual adalah sebuah pendekatan pengukuran kualitas website melalui persepsi pengguna berdasarkan tiga dimensi yaitu usability, information quality dan services interaction quality. Populasi dalam penelitian ini adalah seluruh mahasiswa Universitas XYZ dimana jumlah sampel diambil sebanyak 216 responden secara purposive sampling. Metode penelitian yang digunakan adalah survei dengan kuesioner berbasis WebQual 4.0 yang dianalisis dengan IPA (Importance Performance Analysis untuk mengetahui tingkat kepuasan pelanggan yang merupakan gap antara kepentingan dan kinerja. Hasil uji validitas dan reliabilitasmenunjukkan keseluruhan item kuesioner valid dan reliabel karena telah memenuhi persyaratan. Hasil penelitian menunjukkan bahwa dari 22 item yang dianalisis dengan metode IPA dikelompokkan ke dalam kuadran I (3 item, kuadran II (9 item, kuadran III (7 item dan kuadran IV (3 item. Item yang dianggap penting dan perlu segera ditingkatkan terletak pada kuadran I yaitu kemudahan berkomunikasi melalui web, ketersediaan informasi yang cukup detail serta rasa aman dalam menyampaikan data pribadi. Hasil analisis korelasi ganda juga menunjukkan adanya hubungan yang sangat kuat antara variabel independen dan dependen dalam penelitian ini.*****This study aimed to evaluate the quality of XYZ University website with WebQual approach. WebQual is an approach of measuring the quality of a website through user perception based on three dimensions of usability, information quality and service interaction quality. The population in this study was all students at XYZ University, where the number of samples taken about 216 respondents by purposive sampling. The method survey is used with WebQual 4.0 questionnaire-based that was analyzed by IPA (Importance Performance Analysis to determine the level of customer satisfaction that is the gap between importance and
Quantum kinetic Heisenberg models: a unique dynamics
International Nuclear Information System (INIS)
Timonen, J.; Pilling, D.J.; Bullough, R.K.
1986-01-01
We suggest that the dynamics Glauber embodied in his kinetic Ising model can be introduced similarly and in an apparently unique way, into the quantum statistical mechanics of the quantum-integrable models like the Heisenberg, sine-Gordon and Massive Thirring models. The latter may suggest an extension of the theory to unique kinetic Ising models in two dimensions. The kinetic repulsive bose gas which is studied in detail in the steady state seems to be a solvable kinetic model. (author)
The chirality operators for Heisenberg spin systems
International Nuclear Information System (INIS)
Subrahmanyam, V.
1994-01-01
The ground state of closed Heisenberg spin chains with an odd number of sites has a chiral degeneracy, in addition to a two-fold Kramers degeneracy. A non-zero chirality implies that the spins are not coplanar, and is a measure of handedness. The chirality operator, which can be treated as a spin-1/2 operator, is explicitly constructed in terms of the spin operators, and is given as commutator of permutation operators. (author). 3 refs
Weyl-Heisenberg frames for subspaces
DEFF Research Database (Denmark)
Christensen, Ole
2001-01-01
A Weyl-Heisenberg frame {E(mb)T(na)g}(m, n Z) = {e(2 pi imb(.)) g(.-na)}(m, n is an element of Z) for L-2 (R) allows every function f is an element of L-2(R) to be written as an infinite linear combination of translated and modulated versions of the fixed function g is an element of L-2(R...
On moments-based Heisenberg inequalities
Zozor, Steeve; Portesi, Mariela; Sanchez-Moreno, Pablo; Dehesa, Jesus S.
2011-03-01
In this paper we revisit the quantitative formulation of the Heisenberg uncertainty principle. The primary version of this principle establishes the impossibility of refined simultaneous measurement of position x and momentum u for a (1-dimensional) quantum particle in terms of variances: ⩾1/4. Since this inequality applies provided each variance exists, some authors proposed entropic versions of this principle as an alternative (employing Shannon's or Rényi's entropies). As another alternative, we consider moments-based formulations and show that inequalities involving moments of orders other than 2 can be found. Our procedure is based on the Rényi entropic versions of the Heisenberg relation together with the search for the maximal entropy under statistical moments' constraints ( and ). Our result improves a relation proposed very recently by Dehesa et al.. [1] where the same approach was used but starting with the Shannon version of the entropic uncertainty relation. Furthermore, we show that when a =b, the best bound we can find with our approach coincides with that of Ref. [1] and, in addition, for a = b = 2 the variance-based Heisenberg relation is recovered. Finally, we illustrate our results in the cases of d-dimensional hydrogenic systems.
Analisis Sistem Informasi Akuntansi Penggajian pada PT XYZ
Directory of Open Access Journals (Sweden)
Kriswanto Kriswanto
2013-11-01
Full Text Available Objectives of this research are to analyze accounting information system in PT XYZ, to analyze payroll process in the company, to identify problems and provide recommendations for improvements to the problems found. Method used in this research trying to build the payroll accounting information system was direct observation in the field, consisting initiation and analysis phase. In the analysis phase, research analyzed the problems that occur in the payroll process. Payroll accounting information system, then, will be proposed to support the internal control over the payroll process, and to facilitate the calculation of salaries. Besides, the system is useful to generate reports relating to payroll processing such as attendance reports to see the amount of employee bonuses gained from the attendance every period, accounts payable, employee tax reports and employee salary reports.
Prediksi Pendapatan Sewa Dengan Data Mining Pada Perusahaan XYZ
Directory of Open Access Journals (Sweden)
May Liana
2010-12-01
Full Text Available XYZ Company has a program to predict leasing income that only predict in constant condition where every tenant assumed for leasing renewal. This research is done to build accurate income prediction system that accommodate in making strategic decision towards the company. Premier data collecting is through direct interview with the company management. The analysis is through data training from the previous years to build neural network model. The analysis result shows that this model has produced error total value that is smaller than the previous error total value in years before. Therefore, it could be concluded that data mining with neural network technique that produced more accurate leasing income that could help the company making decision based on the hidden information in the database.
Heisenberg spin glass experiments and the chiral ordering scenario
International Nuclear Information System (INIS)
Campbell, Ian A.; Petit, Dorothee C.M.C.
2010-01-01
An overview is given of experimental data on Heisenberg spin glass materials so as to make detailed comparisons with numerical results on model Heisenberg spin glasses, with particular reference to the chiral driven ordering transition scenario due to Kawamura and collaborators. On weak anisotropy systems, experiments show critical exponents which are very similar to those estimated numerically for the model Heisenberg chiral ordering transition but which are quite different from those at Ising spin glass transitions. Again on weak anisotropy Heisenberg spin glasses, experimental torque data show well defined in-field transverse ordering transitions up to strong applied fields, in contrast to Ising spin glasses where fields destroy ordering. When samples with stronger anisotropies are studied, critical and in-field behavior tend progressively towards the Ising limit. It can be concluded that the essential physics of laboratory Heisenberg spin glasses mirrors that of model Heisenberg spin glasses, where chiral ordering has been demonstrated numerically. (author)
Barrier functions for Pucci-Heisenberg operators and applications
Cutri , Alessandra; Tchou , Nicoletta
2007-01-01
International audience; The aim of this article is the explicit construction of some barrier functions ("fundamental solutions") for the Pucci-Heisenberg operators. Using these functions we obtain the continuity property, up to the boundary, for the viscosity solution of fully non-linear Dirichlet problems on the Heisenberg group, if the boundary of the domain satisfies some regularity geometrical assumptions (e.g. an exterior Heisenberg-ball condition at the characteristic points). We point ...
Heisenberg, his wife s account; Heisenberg, le temoignage de sa femme
Energy Technology Data Exchange (ETDEWEB)
Heisenberg, E.
1990-12-31
A wife tells about her husband life, Werner Heisenberg, Physics Nobel Price in 1932. After a happy childhood, this brilliant student was Albert Einstein, Niels Bohr, Arnold Sommerfeld s student. But at the nazism time, the great physician refused to leave his country, guaranteeing the Hitler regime and taking part in effort of war, that is to say the run to the bomb. The account of Elisabeth Heisenberg, although subjective, allows to understand the scientist s behaviour face terrifying realities of his time. (N.C.).
Analysis of Business Process at PT XYZ by Using SCOR Thread Diagram
Sembiring, M. T.; Rambe, H. C.
2017-03-01
Supply Chain Operations Reference (SCOR) is a standard supply chain performance evaluation model which is proposed by Supply Chain Council (SCC). SCOR makes companies can analyse and evaluate their supply chain performance. SCOR has Thread Diagram which describes business process simply and systematically to help the analysis of company’s business process. This research takes place in PT XYZ that is involved in Crude Palm Oil (CPO) industry. PT XYZ used to be the market leader of CPO industry but nowadays they have a trouble to compete with new competitors. The purpose of this study is to provide the input for PT XYZ business process improvement to enhance the competitiveness of the company with the others. The result obtained shows that there are two performance metrics that are not reached. The analysis of business process shows the lack of control role of PT XYZ to supplier and customer side which is going to be the suggestion of improvement.
PURNANINGSIH, PUTRI RAGIL
2017-01-01
Hotel XYZ explain that reporting customer complaints related to facilities such as facilities and services that are less good. Based on observations of a complaint with every departemen then, to the holding of the study to measure how much the level of interest and satisfaction level of service to customer satisfaction at the Hotel XYZ. The purpose of this research is knowing the level of satisfaction and a customer, determine what attribute the service that needs to be prioritized, the analy...
Location and allocation decision for supply chain network of Cajeput oil (Case in XYZ company)
Mahardika, F. A.; Hisjam, M.; Widodo, B.; Kurniawan, B.
2017-11-01
Cajeput oil is a very promising business. And now, the fulfillment of Cajeput oil in Indonesia is still lacking. It's because the rate of production Cajeput leaves in Indonesia is still low. In Indonesia, XYZ company manages forests in 7 regions. XYZ currently are developing Cajeput oil business. XYZ is currently doing business productivity improvement of Cajeput by planting Cajeput trees in Location 3, Sragen. Besides the Cajeput trees planting program, XYZ plan to do the construction distillery Cajeput leaves. The purpose of the research in this paper is to minimize the total cost of the supply chain network of Cajeput oil in XYZ and to determine whether the construction of a Cajeput distillery should be done or not. This paper uses mixed integer linear programming to make matemathical models. To minimize the total cost, used IBM® ILOG®CPLEX software. From IBM® ILOG®CPLEX software. From the calculation ILOG®CPLEX IBM® software can be seen that the minimum total cost would be obtained if XYZ opened a new distillery with a capacity of 25000kg and a new factory with a capacity of 10000kg. Besides all the truck owned can be used entirely at optimal capacity. And the total cost from IBM® ILOG®CPLEX is IDR 113,406,250.
Discrete Flavour Symmetries from the Heisenberg Group
Floratos, E.G.
2016-01-01
Non-abelian discrete symmetries are of particular importance in model building. They are mainly invoked to explain the various fermion mass hierarchies and forbid dangerous superpotential terms. In string models they are usually associated to the geometry of the compactification manifold and more particularly to the magnetised branes in toroidal compactifications. Motivated by these facts, in this note we propose a unified framework to construct representations of finite discrete family groups based on the automorphisms of the discrete and finite Heisenberg group. We focus in particular in the $PSL_2(p)$ groups which contain the phenomenologically interesting cases.
Heisenberg and the German atomic project
International Nuclear Information System (INIS)
Hermann, A.
1988-01-01
The discovery of nuclear fusion 50 years ago, man's entry into the new atomic age, occurred in a fateful era, marked by the Munich Agreement shortly before and the outbreak of World War II shortly afterwards. Werner Heisenberg, Germany's Number One Physicist, was, on the one hand, respected as a competent and 'useful' theoretician, but on the other, was reviled as a 'white Jew, the spirit of Einstein's spirit'. He plays a key role in answering the question of whether research at that time could have resulted in a German atomic bomb. (orig.) [de
Heisenberg's heirs exploit loopholes in his law
International Nuclear Information System (INIS)
Taubes, G.
1994-01-01
This article describes research into Heisenberg's Uncertainty Principle. Loopholes in the principle have led to a series of experiments using sophisticated optical techniques to extract information from a quantum system without disturbing the variable being measured. The experiments are based on a technique called back-action evasion, which exploits the possibility of channeling all the uncertainty generated by measuring one quantum variable (e.g. laser beam intensity) onto a related variable known as the conjugate observable (beam phase). These experiments and others are described
ANALISIS KELAYAKAN INVESTASI PENAMBAHAN MESIN FRAIS BARU PADA CV. XYZ
Directory of Open Access Journals (Sweden)
Febri Muhammad Rachadian
2013-04-01
Full Text Available Perkembangan teknologi sangat pesat sehingga dunia perindustrian harus mengikuti perkembangannya. Penerapan teknologi diharapkan dapat meningkatkan proses produksi sehingga dapat menghasilkan produk yang berkualitas. Pada industri pembuatan mesin cetak di CV XYZ, mesin-mesin yang digunakan telah hampir lebih dari 20 tahun. Ada indikasi bahwa mesin-mesin tersebut sudah lewat umur pakainya. Alternatif yang digunakan selama ini ialah penggantian komponen yang rusak. Peneliti ingin membandingkan alternative tersebut dengan penambahan mesin frais baru. Untuk itu diperlukan analisis kelayakan investasi penambahan mesin baru. Dalam perkiraan kurun waktu 10 tahun dan suku bunganya 15 % dengan menggunakan NPV, penambahan mesin frais menarik sebesar Rp 461.201.000 dibandingkan penggantian komponen yang rusak sebesar Rp 211.227.000. Sebaliknya pada PBP, penggantian komponen yang rusak masih mengungguli dengan 1 tahun 4 bulan dibandingkan penambahan mesin frais baru selama 2 tahun 1 bulan. Begitupun juga PI penggantian komponen yang rusak masih menarik sebesar 4,2 dibandingkan PI penambahan mesin frais baru sebesar 2,56. Dapat disimpulkan bahwa dalam jangka waktu 10 tahun, alternatif penggantian komponen yang rusak masih lebih baik dibandingkan penambahan mesin frais baru. Namun, untuk investasi jangka panjang, mungkin saja alternatif penambahan mesin frais baru lebih menarik. Kata Kunci: penggantian komponen rusak, mesin frais baru, mesin cetak Abstract The rapid development of technology makes the world of industry must follow its development. Application of technology is expected to improve the production process so it can be produce a quality product. On the industrial manufacture of printing machines in CV XYZ, the machines have been used almost more than 20 years. There are indications that those machines passed the age lifetime. The alternatives that have been used during this time are the replacement of defective parts. Researchers wanted to
Science 101: What, Exactly, Is the Heisenberg Uncertainty Principle?
Robertson, Bill
2016-01-01
Bill Robertson is the author of the NSTA Press book series, "Stop Faking It! Finally Understanding Science So You Can Teach It." In this month's issue, Robertson describes and explains the Heisenberg Uncertainty Principle. The Heisenberg Uncertainty Principle was discussed on "The Big Bang Theory," the lead character in…
Comments on 'On a proposed new test of Heisenberg's principle'
International Nuclear Information System (INIS)
Home, D.; Sengupta, S.
1981-01-01
A logical fallacy is pointed out in Robinson's analysis (J. Phys. A.; 13:877 (1980)) of a thought experiment purporting to show violation of Heisenberg's uncertainty principle. The real problem concerning the interpretation of Heisenberg's principle is precisely stated. (author)
Extended Heisenberg principle: Tentative analysis of its applications
International Nuclear Information System (INIS)
Golbbiewski, A.; Witko, M.
1988-01-01
The paper examines the extension of the Heisenberg principle for a larger number of simultaneously discussed observables. The possibilities of the extended Heisenberg principle are discussed for evaluation of the average value of the square of the selected operator and for evaluation of the standard deviation of the selected operator
Heisenberg and the Framework of Science Policy
Carson, Cathryn
2003-09-01
In the decades after 1945, new structures were created for science policy in the Federal Republic. To the establishment of the post war framework Heisenberg contributed as much as any other figure. This was true even though, on the whole, he took no great pleasure in the venture, nor was he always particularly adept at it. His conceptions revolved around certain key notions: autonomy and centralization, elite advisory bodies and relationships of trust, modernization and international standards. These show up at many levels of his activity, from the Max Planck Society to national and international advisory committees to the Humboldt Foundation itself. His opinions were shaped by encounters in the Federal Republic, but they also grew out of his experience of the Third Reich. At a moment like the present, when the post war settlement is under review, it is interesting to reflect on the inherited system: on the extent to which it reflects the situation of the post war decades and the intuitions of those who, like Heisenberg, created it.
Kelayakan Investasi Perluasan Pabrik Penggilingan Plastik PD XYZ
Directory of Open Access Journals (Sweden)
Hartiwi Prabowo
2012-11-01
Full Text Available PD. PENGGILINGAN PLASTIK XYZ is a company engaged in the manufacturing industry. Recently, demands for products are increasing and the company finds it difficult to meet the demands. Therefore, the company wants to expand the factory to increase output of the products. The purpose of this study is to determine whether the expansion of businesses that want to run is well-worth in terms of financial and nonfinancial aspects. The research method used is descriptive qualitative and quantitative methods. Qualitative descriptive analysis method is used to analyze the legal, technical/operations, markets and marketing, management/organizational, economic, social and environmental impacts. Quantitative descriptive analysis method is used to analyze the financial aspects, the market and marketing. The results of the feasibility study of the factory expansion from the financial aspect refer to an optimistic scenario assumptions and moderate, and worthy to do. Similarly, the non-financial aspects, all aspects point out that the expansion of the factory is feasible to do. By this, the company is expected to maintain a stable supply of raw materials, because, if the supply of raw materials is interrupeted, the operation cannot run.
Implementation of Inventory Management System (IMS) case study on XYZ online store business unit
Bagus Yosan, R.; Kholil, Muhammad; Hanum, Bhetriza
2018-03-01
XYZ baby and child shop is a new player in the business of selling toys and baby gears. Consumers target for XYZ toy shop is segmentation of middle and upper financial ability buyers. XYZ toy store sells imported toys and baby products with high quality products, using international grade production materials and ISO production certificates: 9002. With this conceptual, establishment XYZ business line is as a provider (seller) toys and baby equipment premium brand; then the scope of the product sold must meet all expectations of market demands. Meet the expectations of market demand is not easy; because by fulfilling all expectations, then the impact is the high stock of goods that must be available. The high stock of goods will directly impact on the needs of a large storage area of goods and reduce money. Based on the previous description, the formulation of the problem in this research is: "What inventory management strategy can be applied to improve the productivity of Lean Manufacturing business unit of XYZ online store?"
Quantum stability for the Heisenberg ferromagnet
International Nuclear Information System (INIS)
Bargheer, Till; Beisert, Niklas; Gromov, Nikolay
2008-01-01
Highly spinning classical strings on RxS 3 are described by the Landau-Lifshitz model or equivalently by the Heisenberg ferromagnet in the thermodynamic limit. The spectrum of this model can be given in terms of spectral curves. However, it is a priori not clear whether any given admissible spectral curve can actually be realized as a solution to the discrete Bethe equations, a property which can be referred to as stability. In order to study the issue of stability, we find and explore the general two-cut solution or elliptic curve. It turns out that the moduli space of this elliptic curve shows a surprisingly rich structure. We present the various cases with illustrations and thus gain some insight into the features of multi-cut solutions. It appears that all admissible spectral curves are indeed stable if the branch cuts are positioned in a suitable, non-trivial fashion.
Infinite-range quantum random Heisenberg magnet
Arrachea, Liliana; Rozenberg, Marcelo J.
2002-06-01
We study with exact diagonalization techniques the Heisenberg model for a system of SU(2) spins with S=1/2 and random infinite-range exchange interactions. We calculate the critical temperature Tg for the spin-glass to paramagnetic transition. We obtain Tg~0.13, in good agreement with previous quantum Monte Carlo and analytical estimates. We provide a detailed picture for the different kind of excitations which intervene in the dynamical response χ''(ω,T) at T=0 and analyze their evolution as T increases. We also calculate the specific heat Cv(T). We find that it displays a smooth maximum at TM~0.25, in good qualitative agreement with experiments. We argue that the fact that TM>Tg is due to a quantum disorder effect.
Adelina, W.; Kusumastuti, R. D.
2017-01-01
This study is about business strategy selection for green supply chain management (GSCM) for PT XYZ by using Analytic Network Process (ANP). GSCM is initiated as a response to reduce environmental impacts from industrial activities. The purposes of this study are identifying criteria and sub criteria in selecting GSCM Strategy, and analysing a suitable GSCM strategy for PT XYZ. This study proposes ANP network with 6 criteria and 29 sub criteria, which are obtained from the literature and experts’ judgements. One of the six criteria contains GSCM strategy options, namely risk-based strategy, efficiency-based strategy, innovation-based strategy, and closed loop strategy. ANP solves complex GSCM strategy-selection by using a more structured process and considering green perspectives from experts. The result indicates that innovation-based strategy is the most suitable green supply chain management strategy for PT XYZ.
Heisenberg vortex for light-weight refrigeration of liquid hydrogen
National Aeronautics and Space Administration — Only 83 years ago Werner Karl Heisenberg was awarded the Nobel Prize in physics. His work led to the creation of quantum mechanics, the application of which has,...
Beyond Uncertainty Heisenberg, Quantum Physics, and The Bomb
Cassidy, David C
2010-01-01
Award winning biographer revisits the controversial life of this well known German physicist to shed new light on troubling questions. What can we learn about the relationship of scientific research to state power from Heisenberg's role in Nazi Germany?
Heisenberg's principle of uncertainty and the uncertainty relations
International Nuclear Information System (INIS)
Redei, Miklos
1987-01-01
The usual verbal form of the Heisenberg uncertainty principle and the usual mathematical formulation (the so-called uncertainty theorem) are not equivalent. The meaning of the concept 'uncertainty' is not unambiguous and different interpretations are used in the literature. Recently a renewed interest has appeared to reinterpret and reformulate the precise meaning of Heisenberg's principle and to find adequate mathematical form. The suggested new theorems are surveyed and critically analyzed. (D.Gy.) 20 refs
Effective critical behaviour of diluted Heisenberg-like magnets
Dudka, M.; Folk, R.; Holovatch, Yu.; Ivaneiko, D.
2005-01-01
In agreement with the Harris criterion, asymptotic critical exponents of three-dimensional (3d) Heisenberg-like magnets are not influenced by weak quenched dilution of non-magnetic component. However, often in the experimental studies of corresponding systems concentration- and temperature-dependent exponents are found with values differing from those of the 3d Heisenberg model. In our study, we use the field--theoretical renormalization group approach to explain this observation and to calcu...
Impurity modes in the one-dimensional XXZ Heisenberg model
International Nuclear Information System (INIS)
Sousa, J.M.; Leite, R.V.; Landim, R.R.; Costa Filho, R.N.
2014-01-01
A Green's function formalism is used to calculate the energy of impurity modes associated with one and/or two magnetic impurities in the one-dimensional Heisenberg XXZ magnetic chain. The system can be tuned from the Heisenberg to the Ising model varying a parameter λ. A numerical study is performed showing two types of localized modes (s and p). The modes depend on λ and the degeneracy of the acoustic modes is broken.
Marketing Research of Construction Sites based on ABC-XYZ Analysis and Relational Data
Directory of Open Access Journals (Sweden)
Konikov Aleksandr
2017-01-01
Full Text Available ABC-XYZ analysis is well known in marketing. It allows identifying sites that yield maximum profits when sold, sites that enjoy stable demand, or sites have both qualities specified above. However, the methods are quite abstract and are not designed to study specific factors that impact the results of ABC-XYZ analysis. Meanwhile, for some applications, particularly for marketing research of construction sites, it is critical not only to identify high-profit and stable sites but also to find out what combination of technical parameters, factors related to their location, transport accessibility, etc. are typical of them. This work suggests an approach to address the issue.
Open timelike curves violate Heisenberg's uncertainty principle.
Pienaar, J L; Ralph, T C; Myers, C R
2013-02-08
Toy models for quantum evolution in the presence of closed timelike curves have gained attention in the recent literature due to the strange effects they predict. The circuits that give rise to these effects appear quite abstract and contrived, as they require nontrivial interactions between the future and past that lead to infinitely recursive equations. We consider the special case in which there is no interaction inside the closed timelike curve, referred to as an open timelike curve (OTC), for which the only local effect is to increase the time elapsed by a clock carried by the system. Remarkably, circuits with access to OTCs are shown to violate Heisenberg's uncertainty principle, allowing perfect state discrimination and perfect cloning of coherent states. The model is extended to wave packets and smoothly recovers standard quantum mechanics in an appropriate physical limit. The analogy with general relativistic time dilation suggests that OTCs provide a novel alternative to existing proposals for the behavior of quantum systems under gravity.
ANALISIS DAN PERANCANGAN SISTEM INFORMASI AKUNTANSI PENJUALAN DAN PERSEDIAAN PADA PT XYZ
Directory of Open Access Journals (Sweden)
Martha Viola
2017-12-01
Full Text Available Accounting information system is a system that processes data and transactions to generate useful information for planning, controlling and operating a business. Currently there are still companies that have not implemented an accounting information system one of them is PT XYZ. The recording process at this company still uses manual recording which impacts on the unintegrated performance and the level of data and validity that does not run as expected and the needs of the company. The purpose of this research is to analyze and design the accounting information system sales and inventory that runs and identify the needs and requirements of new systems created so as to improve the weaknesses in the system sales and inventory. The research method used is the analysis and design by doing problem analysis in the running system and then design the flowchart and prototyping of the appropriate system to be applied in PT. XYZ. In analyzing the existing procedures, conducted interviews on related parties at PT. XYZ. The results obtained obstacles and problems in the manual system that runs related to the performance and processes that occur mainly in sales and inventory. In this study resulted in an accounting information system design that is adjusted to help the problems faced by PT. XYZ mainly on sales and inventory recording.
Hanum, Bethriza; Asmarani, Citra
2015-01-01
Sebagai Perusahaan otomotif PT. XYZ perlu melakukan pengembangan dalam produk yang dibuatnya. Proses pengembangan produk ini membutuhkan supplier-supplier baru untuk memasok part pendukung produksi. Untuk itulah dibutuhkan suatu analisa dalam proses pemilihan supplier, dimana proses analisa tersebut menggunakan metode Analytic Hierarchy Process (AHP). Metode ini diperoleh dengan melakukan pemilihan kriteria untuk pemilihan supplier yang meliputi operasional, industrial relation, lingkungan ke...
Microscopic Origin of Heisenberg and Non-Heisenberg Exchange Interactions in Ferromagnetic bcc Fe.
Kvashnin, Y O; Cardias, R; Szilva, A; Di Marco, I; Katsnelson, M I; Lichtenstein, A I; Nordström, L; Klautau, A B; Eriksson, O
2016-05-27
By means of first principles calculations, we investigate the nature of exchange coupling in ferromagnetic bcc Fe on a microscopic level. Analyzing the basic electronic structure reveals a drastic difference between the 3d orbitals of E_{g} and T_{2g} symmetries. The latter ones define the shape of the Fermi surface, while the former ones form weakly interacting impurity levels. We demonstrate that, as a result of this, in Fe the T_{2g} orbitals participate in exchange interactions, which are only weakly dependent on the configuration of the spin moments and thus can be classified as Heisenberg-like. These couplings are shown to be driven by Fermi surface nesting. In contrast, for the E_{g} states, the Heisenberg picture breaks down since the corresponding contribution to the exchange interactions is shown to strongly depend on the reference state they are extracted from. Our analysis of the nearest-neighbor coupling indicates that the interactions among E_{g} states are mainly proportional to the corresponding hopping integral and thus can be attributed to be of double-exchange origin. By making a comparison to other magnetic transition metals, we put the results of bcc Fe into context and argue that iron has a unique behavior when it comes to magnetic exchange interactions.
Coupled channel description for X(3872) and other XYZ mesons
International Nuclear Information System (INIS)
Ortega, P. G.; Ortega, P.G.; Segovia, J.
2009-01-01
state to the X(3872), being the second one a candidate to the X(3940). When the mass difference between neutral and charged states is included a large D 0 D *0 component is found which dominates for large distances and breaks isospin symmetry in the physical state. If we extend the same model to other XYZ charmonium states we get a 2 ++ at M= 3968 MeV which can be identified with the Z(3930), but we do not find any candidate for the Y(3940). As a summary, we have shown that the X(3872) emerges in a constituent quark model calculation as a mixed state of a DD * molecule and χ c1 (2P) state. This framework may explain simultaneously the isospin violation showed by the experimental data and the radiative decay rates. We interpret the X(3940) as the χ c1 (2P) state with a significant DD * component. Within the same model the Z(3930) appears as a 2 ++ charmonium state. (author)
A New XYZ Compliant Parallel Mechanism for Micro-/Nano-Manipulation: Design and Analysis
Directory of Open Access Journals (Sweden)
Haiyang Li
2016-02-01
Full Text Available Based on the constraint and position identification (CPI approach for synthesizing XYZ compliant parallel mechanisms (CPMs and configuration modifications, this paper proposes a new fully-symmetrical XYZ CPM with desired motion characteristics such as reduced cross-axis coupling, minimized lost motion, and relatively small parasitic motion. The good motion characteristics arise from not only its symmetric configuration, but also the rigid linkages between non-adjacent rigid stages. Comprehensive kinematic analysis is carried out based on a series of finite element simulations over a motion range per axis less than ±5% of the beam length, which reveals that the maximum cross-axis coupling rate is less than 0.86%, the maximum lost motion rate is less than 1.20%, the parasitic rotations of the motion stage (MS are in the order of 10−5 rad, and the parasitic translations of the three actuated stages (ASs are in the order of 10−4 of the beam length (less than 0.3% of the motion range, where the beam slenderness ratio is larger than 20. Furthermore, the nonlinear analytical models of the primary translations of the XYZ CPM, including the primary translations of the MS and the ASs, are derived and validated to provide a quick design synthesis. Moreover, two practical design schemes of the proposed XYZ CPM are discussed with consideration of the manufacturability. The practical designs enable the XYZ CPM to be employed in many applications such as micro-/nano-positioning, micro-/nano-manufacturing and micro-/nano-assembly. Finally, a spatial high-precision translational system is presented based on the practical design schemes, taking the actuator and sensor integration into account.
Heisenberg-Langevin versus quantum master equation
Boyanovsky, Daniel; Jasnow, David
2017-12-01
The quantum master equation is an important tool in the study of quantum open systems. It is often derived under a set of approximations, chief among them the Born (factorization) and Markov (neglect of memory effects) approximations. In this article we study the paradigmatic model of quantum Brownian motion of a harmonic oscillator coupled to a bath of oscillators with a Drude-Ohmic spectral density. We obtain analytically the exact solution of the Heisenberg-Langevin equations, with which we study correlation functions in the asymptotic stationary state. We compare the exact correlation functions to those obtained in the asymptotic long time limit with the quantum master equation in the Born approximation with and without the Markov approximation. In the latter case we implement a systematic derivative expansion that yields the exact asymptotic limit under the factorization approximation only. We find discrepancies that could be significant when the bandwidth of the bath Λ is much larger than the typical scales of the system. We study the exact interaction energy as a proxy for the correlations missed by the Born approximation and find that its dependence on Λ is similar to the discrepancy between the exact solution and that of the quantum master equation in the Born approximation. We quantify the regime of validity of the quantum master equation in the Born approximation with or without the Markov approximation in terms of the system's relaxation rate γ , its unrenormalized natural frequency Ω and Λ : γ /Ω ≪1 and also γ Λ /Ω2≪1 . The reliability of the Born approximation is discussed within the context of recent experimental settings and more general environments.
Heisenberg in the atomic age science and the public sphere
Carson, Cathryn
2010-01-01
The end of the Second World War opened a new era for science in public life. Heisenberg in the Atomic Age explores the transformations of science's public presence in the postwar Federal Republic of Germany. It shows how Heisenberg's philosophical commentaries, circulating in the mass media, secured his role as science's public philosopher, and it reflects on his policy engagements and public political stands, which helped redefine the relationship between science and the state. With deep archival grounding, the book tracks Heisenberg's interactions with intellectuals from Heidegger to Habermas and political leaders from Adenauer to Brandt. It also traces his evolving statements about his wartime research on nuclear fission for the National Socialist regime. Working between the history of science and German history, the book's central theme is the place of scientific rationality in public life - after the atomic bomb, in the wake of the Third Reich.
Multi parametric deformed Heisenberg algebras: a route to complexity
International Nuclear Information System (INIS)
Curado, E.M.F.; Rego-Monteiro, M.A.
2000-09-01
We introduce a generalized of the Heisenberg which is written in terms of a functional of one generator of the algebra, f(J 0 ), that can be any analytical function. When f is linear with slope θ, we show that the algebra in this case corresponds to q-oscillators for q 2 = tan θ. The case where f is polynomial of order n in J 0 corresponds to a n-parameter Heisenberg algebra. The representations of the algebra, when f is any analytical function, are shown to be obtained through the study of the stability of the fixed points of f and their composed functions. The case when f is a quadratic polynomial in J 0 , the simplest non-linear scheme which is able to create chaotic behavior, is analyzed in detail and special regions in the parameter space give representations that ca not be continuously deformed to representations of Heisenberg algebra. (author)
Quantum Fourier transform, Heisenberg groups and quasi-probability distributions
International Nuclear Information System (INIS)
Patra, Manas K; Braunstein, Samuel L
2011-01-01
This paper aims to explore the inherent connection between Heisenberg groups, quantum Fourier transform (QFT) and (quasi-probability) distribution functions. Distribution functions for continuous and finite quantum systems are examined from three perspectives and all of them lead to Weyl-Gabor-Heisenberg groups. The QFT appears as the intertwining operator of two equivalent representations arising out of an automorphism of the group. Distribution functions correspond to certain distinguished sets in the group algebra. The marginal properties of a particular class of distribution functions (Wigner distributions) arise from a class of automorphisms of the group algebra of the Heisenberg group. We then study the reconstruction of the Wigner function from the marginal distributions via inverse Radon transform giving explicit formulae. We consider some applications of our approach to quantum information processing and quantum process tomography.
Momentum conservation decides Heisenberg's interpretation of the uncertainty formulas
International Nuclear Information System (INIS)
Angelidis, T.D.
1977-01-01
In the light of Heisenberg's interpretation of the uncertainty formulas, the conditions necessary for the derivation of the quantitative statement or law of momentum conservation are considered. The result of such considerations is a contradiction between the formalism of quantum physics and the asserted consequences of Heisenberg's interpretation. This contradiction decides against Heisenberg's interpretation of the uncertainty formulas on upholding that the formalism of quantum physics is both consistent and complete, at least insofar as the statement of momentum conservation can be proved within this formalism. A few comments are also included on Bohr's complementarity interpretation of the formalism of quantum physics. A suggestion, based on a statistical mode of empirical testing of the uncertainty formulas, does not give rise to any such contradiction
Integrable higher order deformations of Heisenberg supermagnetic model
International Nuclear Information System (INIS)
Guo Jiafeng; Yan Zhaowen; Wang Shikun; Wu Ke; Zhao Weizhong
2009-01-01
The Heisenberg supermagnet model is an integrable supersymmetric system and has a close relationship with the strong electron correlated Hubbard model. In this paper, we investigate the integrable higher order deformations of Heisenberg supermagnet models with two different constraints: (i) S 2 =3S-2I for S is an element of USPL(2/1)/S(U(2)xU(1)) and (ii) S 2 =S for S is an element of USPL(2/1)/S(L(1/1)xU(1)). In terms of the gauge transformation, their corresponding gauge equivalent counterparts are derived.
Magnetization direction in the Heisenberg model exhibiting fractional Brownian motion
DEFF Research Database (Denmark)
Zhang, Zhengping; Mouritsen, Ole G.; Zuckermann, Martin J.
1993-01-01
The temporal magnetization-direction fluctuations in the three-dimensional classical ferromagnetic Heisenberg model have been generated by Monte Carlo simulation and analyzed by the rescaled-range method to yield the Hurst exponent H. A value of H congruent-to 1 has been found to apply in the fer......The temporal magnetization-direction fluctuations in the three-dimensional classical ferromagnetic Heisenberg model have been generated by Monte Carlo simulation and analyzed by the rescaled-range method to yield the Hurst exponent H. A value of H congruent-to 1 has been found to apply...
On the fermionic Heisenberg group and its Q-representation
International Nuclear Information System (INIS)
Frydryszak, A.
1992-01-01
A nonstandard way of representing the canonical anticommutation relations is presented. It is connected with a generalization of the Heisenberg group to a graded phase space. It is shown how Grassmann harmonic analysis can be performed and what are the Q-representations of such a generalized Heisenberg group. As in the conventional case, the Schroedinger and Bargmann-Fock realizations were shown to exist. Grassmann-Hermite polynomials are obtained via the generalized Bargmann transform and new Grassmann-Laguerre polynomials are introduced. (author). 10 refs
Perancangan Sistem Informasi Akuntansi Revenue Cycle dan Inventory Pada PT XYZ
Directory of Open Access Journals (Sweden)
Arta Moro Sundjaja
2010-12-01
Full Text Available PT XYZ is a trading company in electronic equipment distributor of Philips, that needs accounting information system in developing system ongoing manual to be a computerized one. The research method used is analysis method and object-oriented analysis and design (OOAD. The data collecting is through survey of the ongoing system and also interview based on supported theories, which gathered from the books about analysis and system design. The design method is through designing suggested system model. The expected result is sales accounting information system, cash income, and other feature to help PT XYZ in doing events. The result from this research is this information system application could help reduced data searching error transaction by employees. Especially, in reducing errors caused by data record error transaction by employees. This is purposed to every employee could be more focus in doing the events and more responsible in every acts.
Pemeringkatan Pegawai Berprestasi Menggunakan Metode AHP (Analytic Hierarchy Process) di PT. XYZ
Andri Suryadi; Erwin Harahap
2017-01-01
Untuk mendapatkan pegawai terbaik perlu adanya pemeringkatan berdasarkan kriteria yang telah ditetapkan oleh PT XYZ. Salah satu kriteria yang dimaksud adalah kemampuan hard-skills dan soft-skills. Namun, dengan adanya kategori tersebut menjadi sulit bagi pimpinan perusahaan untuk mendapatkan keputusan yang terbaik terutama dalam relasi antar kategori yaitu kolaborasi hard-skills dan soft-skills. Oleh karena itu dibutuhkan suatu metode untuk dapat memeringkatkan pegawai berprestasi sehingga da...
su(1,2) Algebraic Structure of XYZ Antiferromagnetic Model in Linear Spin-Wave Frame
International Nuclear Information System (INIS)
Jin Shuo; Xie Binghao; Yu Zhaoxian; Hou Jingmin
2008-01-01
The XYZ antiferromagnetic model in linear spin-wave frame is shown explicitly to have an su(1,2) algebraic structure: the Hamiltonian can be written as a linear function of the su(1,2) algebra generators. Based on it, the energy eigenvalues are obtained by making use of the similar transformations, and the algebraic diagonalization method is investigated. Some numerical solutions are given, and the results indicate that only one group solution could be accepted in physics
Lin, Jonny
2015-01-01
PT XYZ has faced a problem related to its plastik material ordering system in which its quantity purchase order calculation result was so different with its manual calculation that its material logictic staff was needed to make a proper correction. Therefore, this research was taken in order to help the staff to analyze its root cause so that the proper improvement could be taken and the quantity purchase order calculation will be equal to its manual calculation. By deploying Kepner-Tregoe pr...
Analisa Sistem Ordering Material Plastik pada PT XYZ dengan Kepner-Tregoe Problem Solving
Jonny
2015-01-01
PT XYZ has faced a problem related to its plastik material ordering system in which its quantity purchase order calculation result was so different with its manual calculation that its material logictic staff was needed to make a proper correction. Therefore, this research was taken in order to help the staff to analyze its root cause so that the proper improvement could be taken and the quantity purchase order calculation will be equal to its manual calculation. By deploying Kepner-Tregoe pr...
PENGARUH KOMUNIKASI PEMASARAN TERHADAP LOYALITAS NASABAH (STUDI KASUS BANK XYZ SYARIAH CABANG BOGOR
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Rahmatullah Rahmatullah
2014-03-01
Full Text Available The existence of printings and electronics media stimulates business owner, not only in the offering of the products and service quality, but also solid positioning implementations through quality standard and service quality. These particular effort intends to overwhelm the mind of customer through products and services offered. Communications Marketing Strategy Planning becomes irresistibly required to prevent loss from mistaken implementations of Marketing Communications. In accordance to the Marketing Communications Programs taken gradually by XYZ Syariah Bank, Writer intends to understand the Customer Loyalty of XYZ Syariah, also to discover further connections between Marketing Communication and Customer Loyalty, and identifying the customer expectations and the performance of marketing communications programs Research Method are descriptive correlations, data gathering by questionnaires, data processed by SPSS 13,0. Minitab 14 for IP Matrix presentation, linear numeric scale of semantic differential, Spearman Correlations Analysis, research population is the customers of XYZ Syariah Bank, therefore the sample are 60 persons using judgment sampling techniques in sample drawings. Result indicates 78% of customers are loyal, few programs positively related tocustomers loyalty, which is image buildings, sponsorships, attractively cheap margin and high profit sharing. For customer opinion on proper performance and importance programs are image buildings, cheap margin for financing, and high profit share in funding. On sought to results, XYZ Syariah Bank may emphasize on programs related in positive fashion with customer loyalty, yet improves other marketing communications programs. Customer loyalty also need to be look after, as same as performance of marketing communications programs, in order to fit customers perceptions of importance.
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Pertiwi Andaran
2015-09-01
Full Text Available The exploration and production process of oil and its supporting operations always generates waste as by-product. If they are uncontrolled, it might decrease the environmental quality. Thus, it is necessary to manage and treat the waste in order to meet the regulation standard of quality and quantity. PT XYZ is an energy company, particularly oil and gas production, which its production activity generate a large amount of waste as well as produced water. Thus, PT XYZ must have facilities or produced water handling plant which could minimize pollution caused by produced water. PT XYZ already has a system of produced water handling with recycling principle. After oil and water separation including water treating at Water Treating Plant (WTP, produced water will be used for steam injection. This is the part of enhanced oil recovery by steam flooding in Duri Field. Besides, produced water could be used as backwash water at WTP, that is Oil Removal Filter (ORF and Water Softener, which is called brine water. If the produced water and brine water is over load the capacity of oil enhanced recovery injection, it might be disposed through injection to Disposal Well and there are certain condition that produced water should be discharged into canal. The objective f this study is to analyze the performance of a water treating plant in PT XYZ. Water Treating Plant is a facility for treating produced water. Basically, WTP is on good condition and each unit has high efficiency for separating oil and water (60-99%. Horizontal velocity at pit #A of API Separator was larger than the design criteria. In addition, Water Softeners have efficiency until 99% for the hardness.
IMPROVING PERFORMANCE OF BISCUIT PRODUCTION PROCESS THROUGH LEAN SIX-SIGMA AT PT XYZ
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Ahmad Mukti Almansur
2017-05-01
Full Text Available This research aims to analyze waste or loss using the 7-waste approach and value added/non value added activities in the production process at PT. XYZ. This research also aims to evaluate the production process capability and sigma values at PT. XYZ and used DMAIC technique (Define, Measure, Analysis, Improvement, and Control from Lean Six-sigma with an analysis using Failure Mode and Effect Analysis (FMEA. The results of the research obtained the values of Process Cycle Efficiency (PCE of 47.29%, CTQ (Critical to Quality and process capability value in the form of Cpm (Capability Index for each process stage and yield. Line-5 has DPMO (Defects per Million Opportunities value of 29,632,607 with a Sigma Score 3.39, and FMEA (Failure Mode and Effect Analysis analysis resulted in recommendations for improvement at each process stage.Keywords: process cycle efficiency, biscuit, lean six-sigma, CTQ, CpmABSTRAKPenelitian ini bertujuan melakukan analisis tingkat pemborosan (waste/loss dengan menggunakan pendekatan 7 waste dan value added/non value added activity dalam proses produksi di PT. XYZ. Selanjutnya, melakukan evaluasi terhadap nilai kapabilitas proses produksi dan nilai sigma di PT. XYZ. Penelitian ini menggunakan teknik DMAIC (Define, Measure, Analysis, Improvement, and Control dari Lean Six Sigma dengan Analisis menggunakan menggunakan alat Failure Mode and Effect Analysis (FMEA. Hasil Penelitian mendapati nilai Process Cycle Efficiency (PCE 47.29%, CTQ (Critical to Quality dan nilai kapabilitas proses berupa Cpm (Capability Index setiap tahapan proses dan Yield. Line-5 memiliki DPMO (Defects Per Million Opportunities sebesar 29632.607 dengan Sigma Score 3.39 Sigma, analisis FMEA(Failure Mode and Effect Analysis menghasilkan rekomendasi perbaikan di setiap tahapan proses.Kata kunci: process cycle efficiency, biskuit, lean six sigma, CTQ, Cpm
Sidarahardja, Stephanie; Susanto, Santhio Ardy
2014-01-01
As much as employees important for an organization, motivation becomes the main concern of the employees management to determine the successful performance of the employees. This also happens in PT. XYZ in which the management has put some efforts to increase the motivation among the Personal Relationship Managers (PRMs) since based on the performance in 2013, only 30% among 236 were able to perform above the Key Performance Indicators (KPI) standards. For motivation becomes the biggest s...
Analysis on Cost Efficiency Impact in PT XYZ ADKAR and HERO Theory
Miscel, Miscel; Bangun, Yuni Ros
2013-01-01
Today the world of telecommunications experience intense competition, not only for the operators but also for vendors and suppliers. Competition tariff making operators also reduce the cost of network devices and service / maintance. It affects all network equipment providers or vendors. Each vendor trying to offer competitive prices for the operator. Yet the competition among vendors themselves. PT XYZ as one of the network equipment providers strive to remain competitive and survive in the ...
The Bohr-Heisenberg correspondence principle viewed from phase space
DEFF Research Database (Denmark)
Dahl, Jens Peder
2002-01-01
Phase-space representations play an increasingly important role in several branches of physics. Here, we review the author's studies of the Bohr-Heisenberg correspondence principle within the Weyl-Wigner phase-space representation. The analysis leads to refined correspondence rules that can...
Phonon dynamics in a compressible classical Heisenberg chain
Fivez, Jan; Raedt, Hans De; Raedt, Bart De
1980-01-01
The dynamic properties of the compressible classical Heisenberg chain with bilinear coupling are investigated. The sound velocity is calculated exactly. The Fourier-transformed displacement-displacement correlation function is studied as a function of temperature, wave vector, and the model
A Poisson type formula for Hardy classes on Heisenberg's group
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Lopushansky O.V.
2010-06-01
Full Text Available The Hardy type class of complex functions with infinite many variables defined on the Schrodinger irreducible unitary orbit of reduced Heisenberg group, generated by the Gauss density, is investigated. A Poisson integral type formula for their analytic extensions on an open ball is established. Taylor coefficients for analytic extensions are described by the associatedsymmetric Fock space.
Chiral mixed phase in disordered 3d Heisenberg models
Bekhechi, S.; Southern, B. W.
2004-01-01
Using Monte Carlo simulations, we compute the spin stiffness of a site-random 3d Heisenberg model with competing ferromagnetic and antiferromagnetic interactions. Our results for the pure limit yield values of the the critical temperature and the critical exponent $\
Spin Waves in a Classical Compressible Heisenberg Chain
Fivez, J.; Raedt, H. De
1980-01-01
The effect of the spin—lattice interaction on the spin dynamics of a classical Heisenberg chain is studied by means of a truncated continued fraction. At low temperature, the spin correlation length and the spin wave frequency show the same simple dependence on the coupling.
Generalized Heisenberg algebra and (non linear) pseudo-bosons
Bagarello, F.; Curado, E. M. F.; Gazeau, J. P.
2018-04-01
We propose a deformed version of the generalized Heisenberg algebra by using techniques borrowed from the theory of pseudo-bosons. In particular, this analysis is relevant when non self-adjoint Hamiltonians are needed to describe a given physical system. We also discuss relations with nonlinear pseudo-bosons. Several examples are discussed.
ANALISIS PERSEPSI DEVELOPER TERHADAP PRODUK KREDIT PEMILIKAN RUMAH (KPR BANK XYZ CABANG BOGOR
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Yuni Krisnawati
2011-08-01
Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 The result of the study showed that respondent had difference perception about Bank XYZ Housing loan (KPR product and other bank. There are eleven attributes as respondent factors in choosing Housing loan (KPR product applied in this research, the attributes are interest rate, term and conditions loan, down payment, fees and chargers, credit process, product information, services from account officer, sales fee (commision, event of gathering and bank location. According to perception of respondent there are five excellences of mortgage product Bank XYZ, that is having term loan that is sufficiently long, down payment which is light, credit process that is quickly, event of gathering which is good enough and good location. Bank XYZ need strategy to increase Housing loan product, such as increase sales fee or reward to sales developer by giving special program and interesting reward, gives service marketing satisfying, competing interest rate, Meanwhile the management has to maintains good enough have been credit process and more improved again, because according to perception of respondent a real important attributes are sales fee for sales developer, interest rate and credit process. That attributes also becomes main preference according to respondent perception.
Business Impact Analysis Terkait Penanganan dan Pemulihan Terhadap Bencana di PT Bank XYZ
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Rubil Rubil
2012-12-01
Full Text Available For each company, disasters may have diverse impacts either financially or non-financially. Therefore, a company requires a business continuity plan. One important factor in developing such plan is Business Impact Analysis (BIA. With BIA, a company can identify and analyze Critical Business Functions (CBFs and potential impacts on the business whether operationally or financially, and further, business recovery priority, strategy and solution can be determined following a disaster.Methodologies used in developing this BIA are quantitativeand qualitative where for aspects related to financials, quantitive method is used. Meanwhile, for those aspects\\ related to non-financial areas, qualitative method is used. The development of this BIA was done through the dissemination of questionnaires to 62 business units in PT Bank XYZ. To draw the BIA, eight parameters were used, where as for the final result, there were three criticality levels found in the business units of PT Bank XYZ, i.e. very critical level - 18 business units (29%, critical level - 23 business units (37% and less critical level – 21 business units (34%. In addition, there were 71 applications used by CBFs. Based on the results of this study, PT Bank XYZ can determine the priority and key strategies for business units that require handling and recovery when a disaster occurs to maintain the bank's business operation's continuity and sustainability.Withthat, the company can minimize the potential loss resulted from a disaster.
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Kornelius Irfandhi
2016-03-01
Full Text Available Information Technology (IT is increasingly progressing. Nowadays, the success of a business of the organization/company is highly dependent on the IT infrastructure used. Therefore, organizations/companies have to manage their IT service to be optimal to their customers. Looking at this matter and the increasing dynamics of XYZ University, then Data and Information System Center (Pusdatin - an IT provider of XYZ University began implementing IT Service Management (ITSM from 2013 using the latest version of Information Technology Infrastructure Library (ITIL, namely ITIL v3 as a framework for implementing ITSM in its business processes. However, along the way, there are still some problems happen in Pusdatin in order that ITSM can actually support and align with the objectives of XYZ University. Through this paper, the authors want to explain how the implementation of ITSM at Pusdatin, identify the problems related to the implementation of ITSM, and provide the solutions for each problem. The methods used are direct observation to Pusdatin, conductan interview with the Head of Pusdatin and Staff of Pusdatin, and also perform a literature review of books and papers that discuss about ITIL. The result of this research is that ITSM process of Pusdatin generally works quite well but there are still some shortcomings because ITSM is not 100% implemented in all areas.
Euler-Heisenberg-Weiss action for QCD +QED
Ozaki, Sho; Arai, Takashi; Hattori, Koichi; Itakura, Kazunori
2015-07-01
We derive an analytic expression for one-loop effective action of QCD +QED at zero and finite temperatures by using the Schwinger proper time method. The result is a nonlinear effective action not only for electromagnetic and chromo-electromagnetic fields but also for the Polyakov loop, and thus reproduces the Euler-Heisenberg action in QED, QCD, and QED +QCD , and also the Weiss potential for the Polyakov loop at finite temperature. As applications of this "Euler-Heisenberg-Weiss" action in QCD +QED , we investigate quark pair productions induced by QCD +QED fields at zero temperature and the Polyakov loop in the presence of strong electromagnetic fields. Quark one-loop contribution to the effective potential of the Polyakov loop explicitly breaks the center symmetry, and is found to be enhanced by the magnetic field, which is consistent with the inverse magnetic catalysis observed in lattice QCD simulation.
Critical properties of the Kitaev-Heisenberg Model
Sizyuk, Yuriy; Price, Craig; Perkins, Natalia
2013-03-01
Collective behavior of local moments in Mott insulators in the presence of strong spin-orbit coupling is one of the most interesting questions in modern condensed matter physics. Here we study the finite temperature properties of the Kitaev-Heisenberg model which describe the interactions between the pseudospin J = 1 / 2 iridium moments on the honeycomb lattice. This model was suggested as a possible model to explain low-energy physics of AIr2O3 compounds. In our study we show that the Kitaev-Heisenberg model may be mapped into the six state clock model with an intermediate power-law phase at finite temperatures. In the framework of the Ginsburg-Landau theory, we provide an analysis of the critical properties of the finite-temperature ordering transitions. NSF grant DMR-1005932
[Carl Friedrich von Weizsäcker and Werner Heisenberg].
Cassidy, David C
2014-01-01
The 50-year relationship between Weizsäcker and Heisenberg spanned the highpoints of discovery and dictatorship during the 1930s, extended into the war-time uranium project, the post-war controversy over that project, debates over West German nuclear policy, and the philosophical implications of modern physics. This paper explores the interaction between these two leading figures during that difficult and significant half-century.
PENGENDALIAN PERSEDIAAN BAHAN BAKU BASE MATERIAL PADA INDUSTRI KERAMIK DI PT. XYZ
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Lidya Susanti
2015-12-01
Full Text Available Inventory of raw materials in the company is very important, so it has to be controlled. A good inventory control of raw materials should be supported with cost efficiency. This study was to analyze factors that cause the base material inventories excess at PT. XYZ and analyze the purpose of the base material inventories to be controlled. The reseacrh was using a fish bone method and continue with using pairwise comparison method assisted with the expert choice 2000 software. The classification result based on ABC analysis, the selected item that was going to be analyzed was the A category items.The items that are included in the A category are clay ex belitung jw, clay ja 1/ja b and sodium feldspar. The EOQ equations model was used to answer the purpose of the base material inventories control. Based from the EOQ model, the needed quantity, order quantity, order frequency, reorder point (ROP, total order cost (TOC, total carrying cost (TCC, and total inventory cost (TIC could be obtained. The comparison of the total cost of inventory among the EOQ model and company policies showed that the EOQ model in seven months can save up to Rp311.612.769. PT. XYZ could minimize the base material inventory costs by calculating the costs incurred. The EOQ model could be implemented if all of the departments involved are well cooperated. PT. XYZ should also be able to make inventory control standards which are quantity order, order frequency, and reorder point. Keywords: Cost, EOQ, frequency, inventory, ROPABSTRAKPersediaan bahan baku pada perusahaan sangatlah penting, sehingga harus dapat dikendalikan. Pengendalian persediaan bahan baku yang baik harus didukung dengan efisiensi biaya. Penelitian ini untuk menganalisis faktor-faktor yang menyebabkan kondisi persediaan bahan baku base material berlebih di PT. XYZ dan menganalisis persediaan bahan baku base material agar dapat dikendalikan. Penelitian ini menggunakan metode fish bone dilanjutkan dengan metode
Improved quantum circuit modelling based on Heisenberg representation
Lee, Y. H.; Khalil-Hani, M.; Marsono, M. N.
2018-02-01
Heisenberg model allows a more compact representation of certain quantum states and enables efficient modelling of stabilizer gates operation and single-qubit measurement in computational basis on classical computers. Since generic quantum circuit modelling appears intractable on classical computers, the Heisenberg representation that makes the modelling process at least practical for certain circuits is crucial. This paper proposes efficient algorithms to facilitate accurate global phase maintenance for both stabilizer and non-stabilizer gates application that play a vital role in the stabilizer frames data structure, which is based on the Heisenberg representation. The proposed algorithms are critical as maintaining global phase involves compute-intensive operations that are necessary for the modelling of each quantum gate. In addition, the proposed work overcomes the limitations of prior work where the phase factors due to non-stabilizer gates application was not taken into consideration. The verification of the proposed algorithms is made against the golden reference model that is constructed based on the conventional state vector approach.
BUSINESS MODEL IN ELECTRICITY INDUSTRY USING BUSINESS MODEL CANVAS APPROACH; THE CASE OF PT. XYZ
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Achmad Arief Wicaksono
2017-01-01
Full Text Available The magnitude of opportunities and project values of electricity system in Indonesia encourages PT. XYZ to develop its business in electrical sector which requires business development strategies. This study aims to identify company's business model using Business Model Canvas approach, formulate business development strategy alternatives, and determine the prioritized business development strategy which is appropriate to the manufacturing business model for PT. XYZ. This study utilized a descriptive approach and the nine elements of the Business Model Canvas. Alternative formulation and priority determination of the strategies were obtained by using Strengths, Weaknesses, Opportunities, Threats (SWOT analysis and pairwise comparison. The results of this study are the improvement of Business Model Canvas on the elements of key resources, key activities, key partners and customer segment. In terms of SWOT analysis on the nine elements of the Business Model Canvas for the first business development, the results show an expansion on the power plant construction project as the main contractor, an increase in sales in its core business in supporting equipment industry of oil and gas, a development in the second business i.e. an investment in the electricity sector as an independent renewable emery-based power producer. On its first business development, PT. XYZ selected three Business Model Canvas elements which become the priorities of the company i.e. key resources weighing 0.252, key activities weighing 0.240, and key partners weighing 0.231. On its second business development, the company selected three elements to become their the priorities i.e. key partners weighing 0.225, customer segments weighing 0.217, and key resources weighing 0.215.Keywords: business model canvas, SWOT, pairwise comparison, business model
A Boundary Element-Response Matrix method for criticality diffusion problems in xyz geometry
International Nuclear Information System (INIS)
Cossa, G.; Giusti, V.; Montagnini, B.
2010-01-01
The Boundary Element-Response Matrix (BERM) method shown in the paper aims to represent an alternative to the Finite Element method in order to solve 3D multigroup diffusion (criticality) problems in xyz geometry. The theory extends the previous work on the diffusion equations in two dimensions and new techniques for the evaluation of the integrals involved in the boundary integral equations, as well as new procedures for solving the resulting linear system, have greatly enhanced the performances of the method. Results show that BERM can achieve an excellent accuracy, still keeping a good computational efficiency.
Productivity improvement in the production line with lean manufacturing approach: case study PT. XYZ
diah Halimatussa’; Parkhan Ali; Sugarindra Muchamad
2018-01-01
The increaseing productivity is one of the competitive strategies that can be applied in a company in order to survive in an intense competitive presure. PT. XYZ is a textile industry manufacturing golf gloves and caddy bag. Every day, the company has a production target of 600 pieces per line. However, the desired target is not achieved that it will affect the delay in delivery of products to customers. In this research, a case study on implementing value stream mapping and Kaizen as the lea...
Modern or Anti-modern Science? Weimar Culture, Natural Science and the Heidegger-Heisenberg Exchange
Carson, Cathryn
The following sections are included: * Weimar Culture and Scientific Rationality * Heidegger Read Historically * Science and Crisis * Quantum Mechanics and the Heidegger-Heisenberg Exchange * Conclusion * Acknowledgments
STRATEGI PENGEMBANGAN PORTOFOLIO PRODUK DIVISI PENERBITAN BUKU-BUKU PERGURUAN TINGGI PT XYZ
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Otto Zulham
2016-01-01
Full Text Available The study aims to help XYZ Company formulate development strategies on the portfolio of college book products. XYZ Company currently has four divisions, each targeting a different segment. To formulate a development strategy, this study used a portfolio of General Electric Matrix (GE and Analysis of Product Life Cycle (PLC. GE Matrix results showed that the categories of the Islamic religion, economics and management, health sciences, social sciences and political education are in the first quadrant, i.e. the appeal in the industry is still high for these categories which were offset by high strength of the company's business. Categories of legal science and psychology are in quadrant II, i.e. the company has a high business strength, but the attractiveness of the industry for these categories is in medium level. The analysis result of PLC, i.e. the Islamic religion, economics and management, psychology, political science are in higher phase, legal studies in a growth phase, while the health and education sciences are in the lower phase. The formulation of strategies for the development of Islamic religion, economics and managements, social and politics is performed by using intensive growth strategy, the market growth strategy, market development strategy, and integrative strategies, legal science and psychology with intensive growth strategy, while health and education sciences with intensive and defensive strategies.Keywords: publishing company, the college book division, GE matrix, PLC analysis
Widodo, L.; Adianto; Sartika, D. I.
2017-12-01
PT. XYZ is a large automotive manufacturing company that manufacture, assemble as well as a car exporter. The other products are spare parts, jig and dies. PT. XYZ has long been implementing the Occupational Safety and Health Management System (OSHMS) to reduce the potential hazards that cause work accidents. However, this does not mean that OSHMS that has been implemented does not need to be upgraded and improved. This is due to the potential danger caused by work is quite high. This research was conducted in Sunter 2 Plant where its production activities have a high level of potential hazard. Based on Hazard Identification risk assessment, Risk Assessment, and Risk Control (HIRARC) found 10 potential hazards in Plant Stamping Production, consisting of 4 very high risk potential hazards (E), 5 high risk potential hazards (H), and 1 moderate risk potential hazard (M). While in Plant Casting Production found 22 potential hazards findings consist of 7 very high risk potential hazards (E), 12 high risk potential hazards (H), and 3 medium risk potential hazards (M). Based on the result of Fault Tree Analysis (FTA), the main priority is the high risk potential hazards (H) and very high risk potential hazards (E). The proposed improvement are to make the visual display of the importance of always using the correct Personal Protective Equipment (PPE), establishing good working procedures, conducting OSH training for workers on a regular basis, and continuing to conduct safety campaigns.
Recent empirical developments in the study and understanding of XYZ states
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Shen Chengping
2016-01-01
Full Text Available Exotic hadronic states beyond the conventional quark model (called charmoniumlike/bottomoniumlike states or XYZ particles have been searched for and many candidates were proposed including glueballs, hybrids, multi-quark states, hadron molecules, etc. Dramatic progress was made in the study of the exotic states after the running of the two B-factories, i.e., Belle at KEK and BaBar at SLAC. In my review report, I present the most recent results on the study of the XYZ states from the BESIII, Belle, BaBar, LHCb, CMS experiments, etc., including (1 X states: the observation of the X(3872 in e+e− → γX(3872 at around 4.26 GeV; searches for the Xb state; (2 Y states including the updated results for the Y(4008, Y(4260, Y(4360, Y(4660, etc; (3 Z states including the observations of the Z(4430, Z1(4050, Z2(4250, Zc(3900, Zc(4020, Zc(4200; the evidence for the Zc(4050± → π±ψ(2S ; search for the Zcs in e+e− → K+K−J/ψ.
Recent empirical developments in the study and understanding of XYZ states
Shen, Chengping
2016-07-01
Exotic hadronic states beyond the conventional quark model (called charmoniumlike/bottomoniumlike states or XYZ particles) have been searched for and many candidates were proposed including glueballs, hybrids, multi-quark states, hadron molecules, etc. Dramatic progress was made in the study of the exotic states after the running of the two B-factories, i.e., Belle at KEK and BaBar at SLAC. In my review report, I present the most recent results on the study of the XYZ states from the BESIII, Belle, BaBar, LHCb, CMS experiments, etc., including (1) X states: the observation of the X(3872) in e+e- → γX(3872) at around 4.26 GeV; searches for the Xb state; (2) Y states including the updated results for the Y(4008), Y(4260), Y(4360), Y(4660), etc; (3) Z states including the observations of the Z(4430), Z1(4050), Z2(4250), Zc(3900), Zc(4020), Zc(4200); the evidence for the Zc(4050)± → π±ψ(2S); search for the Zcs in e+e- → K+K-J/ψ.
Improving The Average Session Evaluation Score Of Supervisory Programby Using PDCA Cycle At PT XYZ
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Jonny Jonny
2016-09-01
Full Text Available PT XYZ took People Development tasks as important things in order to provide great leaders for handling its business operations. It had several leadership programs such as basic management program, supervisory program, managerial program, senior management program, general management program, and the executive program. For basic management and supervisory programs, PT XYZ had appointed ABC division to solely handled them, while the rest, ABC division should cooperate with other training providers who were reputable in leadership ones. The aim of this study was to ensure that the appropriate leadership style has been delivered accordingly to the guideline to the employees by ABC division to improve the average session evaluation score of the supervisory program by using PDCA (Plan, Do, Check, and Action cycle. The method of this research was by gathering quantitative and qualitative data by using session and program evaluation format to see current condition. The research finds that the reasons why the program is below target 4,10 score. It is related to the new facilitator, no framework, and teaching aids.
PERANCANGAN RENCANA STRATEGIS SISTEM INFORMASI DAN TEKNOLOGI INFORMASI (SI/TI: STUDI KASUS STMIK XYZ
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Maryani Maryani
2010-10-01
Full Text Available Nowadays, business activity in every organization will not be parted from information system (IS and information technology (IT. STMIK XYZ is one private college that has a good business growth. In order to reach the objective of the college in its vision and mission, it needs business strategy and IS/IT strategy. The basic concept in arranging framework IS/IT strategic planning in STMIK XYZ is John Ward and Joe Peppard’s concept. The framework of IS/IT strategic planning consists of 5 steps, that are initialization preparation strategic planning of IS/IT, understanding business and information needs, defining target of IS/IT, defining strategic IS/IT, and planning and implementation. Strategic analysis uses PEST analysis method, BCG matrix analysis, five Porter power analysis, SWOT analysis, value chain analysis, CSF and KPI analysis. The research result is to make a framework of IS/IT integrated strategic planning so it could ease the management to manage resources to produce information that needed, accurate, and could be used by anybody.Keywords: planning, business strategy, IS/IT strategy, information system strategic planning, Ward & Peppard method.
Usulan Perbaikan Kualitas Penggulungan Benang Nilon Dengan Menggunakan Metode Six Sigma di PT. XYZ
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I Wayan Sukania
2016-07-01
Full Text Available Abstrak: PT. XYZ merupakan perusahaan yang bergerak dibidang textil yang memproduksi benang jahit. Perusahaan selalu berusaha meningkatkan kualitas produknya dalam penanganan produk yang cacat yang terjadi pada proses produksi karena jumlah cacat yang timbul cukup banyak. Untuk itu perlu dilakukan tindakan perbaikan dalam menurunkan tingkat cacat yang terjadi. Pada penelitian ini, penulis menggunakan metode six sigma dengan model perbaikian Define-Measure-Analyze-Improve-Control (DMAIC dan Failure Mode and Effect Analysis (FMEA untuk menganalisis kinerja proses dan produk yang dihasilkan. Penerapan metode tersebut diharapakan mampu meningkatkan kualitas perusahaan yang sekarang pada level sigma 3,8 menuju tingkat kinerja kualitas 6 Sigma. Kata kunci: Six Sigma, FMEA Abstract: PT. XYZ is a company engaged in textile-producing sewing thread. The company is always trying to improve the quality of products due to quite a lot of products defects occur in the production process. It is necessary for corrective action in reducing the level of defects that occur. In this research, the six sigma with Define-Measure Analyze-Improve-Control (DMAIC and Failure Mode and Effect Analysis (FMEA models were used to analyze the performance of processes and products. Application of those methods are expected to be able to improve the quality of company that are now at the level of sigma 3,8 to 6 sigma level of quality performance . Keywords: Six Sigma, FMEA
Water footprint and life cycle assessment of concrete roof tile and brick products at PT. XYZ
Octavia, Caesara; Laurence; Hartono, Natalia
2017-12-01
PT. XYZ is an Indonesian company engaged in manufacturing concrete roof tile and paving block. The company has not paid attention to the environmental and human health aspects of their production activity, where there is so much water used and discarded during the production process and no water treatment for the wastewater produced. Therefore this topic proposed in order to determine the resulting impacts from the production processes of concrete roof tile and brick at PT. XYZ on the environment and human health. The impact on the environment and human health were identified through water footprint assessment (WFA) and life cycle assessment (LCA). Through the WFA accounting, it is known that the amount of water needed to produce a concrete roof tile is 21.384 L which consists of 16.433 L blue water and 4.951 L grey water, whereas for a brick is 10.496 L which consists of 10.48 L blue water and 0.016 L grey water. With ReCiPe midpoint (H) method, it is known that the dominant impact categories generated in one batch production processes of concrete roof tile and brick are natural land transformation, marine eco-toxicity, freshwater eutrophication, and freshwater eco-toxicity, where those impact categories represent the average of 75.5% from overall impact category for concrete roof tile and brick products.
Spin-density functional for exchange anisotropic Heisenberg model
International Nuclear Information System (INIS)
Prata, G.N.; Penteado, P.H.; Souza, F.C.; Libero, Valter L.
2009-01-01
Ground-state energies for antiferromagnetic Heisenberg models with exchange anisotropy are estimated by means of a local-spin approximation made in the context of the density functional theory. Correlation energy is obtained using the non-linear spin-wave theory for homogeneous systems from which the spin functional is built. Although applicable to chains of any size, the results are shown for small number of sites, to exhibit finite-size effects and allow comparison with exact-numerical data from direct diagonalization of small chains.
Spin stiffness of frustrated Heisenberg antiferromagnets: Finite size scaling
International Nuclear Information System (INIS)
Feiguin, A.E.; Gazza, C.J.; Trumper, A.E.
1995-07-01
We calculate the spin stiffness of the S = 1/2 frustrated Heisenberg antiferromagnet on finite square lattices by means of the Schwinger - boson approach. COmparison with recent exact numerical results reveals that the observed lack of scaling with lattice size for intermediate to large frustration cannot be taken as an indication of absence of Neel order. This lack of scaling is already apparent for small frustration and is a finite lattice effect. Our results also indicate that the expected behaviour is regained for larger lattices than those considered in numerical studies. (author). 18 refs, 2 figs
Simulation of time-dependent Heisenberg models in one dimension
DEFF Research Database (Denmark)
Volosniev, A. G.; Hammer, H. -W.; Zinner, N. T.
2016-01-01
constants can be manipulated by time-dependent driving of the shape of the external confinement. As illustrative examples, we consider a harmonic trapping potential with a variable frequency and an infinite square well potential with a time-dependent barrier in the middle.......In this Letter, we provide a theoretical analysis of strongly interacting quantum systems confined by a time-dependent external potential in one spatial dimension. We show that such systems can be used to simulate spin chains described by Heisenberg Hamiltonians in which the exchange coupling...
Finite-temperature correlation functions of Heisenberg antiferromagnet
International Nuclear Information System (INIS)
Izergin, A.G.; Korepin, V.E.; Slavnov, N.A.
1988-01-01
The finite-temperature correlation functions in the one-dimensional Heisenberg XXZ magnet are investigated in the framework of the quantum inverse scattering method. On the transition to nonzero temperatures, it is necessary in this case to solve a number of basically new problems. The main one of these is related to the fact that the ground state of the Hamiltonian (physical vacuum) at nonzero temperature (more precisely, the state of thermodynamic equilibrium) includes many species of particles - not only elementary particles but also bound states of them. We give an appropriate generalization of the method
Moments of general Heisenberg Hamiltonians up to sixth order
Schmidt, Heinz-Juergen; Lohmann, Andre; Richter, Johannes
2010-01-01
We explicitly calculate the moments t_n of general Heisenberg Hamiltonians up to sixth order. They have the form of finite sums of products of two factors, the first factor being represented by a multigraph and the second factor being a polynomial in the variable s(s + 1), where s denotes the individual spin quantum number. As an application we determine the corresponding coefficients of the expansion of the free energy and the zero field susceptibility in powers of the inverse temperature. T...
Collective impurity effects in the Heisenberg triangular antiferromagnet
International Nuclear Information System (INIS)
Maryasin, V S; Zhitomirsky, M E
2015-01-01
We theoretically investigate the Heisenberg antiferromagnet on a triangular lattice doped with nonmagnetic impurities. Two nontrivial effects resulting from collective impurity behavior are predicted. The first one is related to presence of uncompensated magnetic moments localized near vacancies as revealed by the low-temperature Curie tail in the magnetic susceptibility. These moments exhibit an anomalous growth with the impurity concentration, which we attribute to the clustering mechanism. In an external magnetic field, impurities lead to an even more peculiar phenomenon lifting the classical ground-state degeneracy in favor of the conical state. We analytically demonstrate that vacancies spontaneously generate a positive biquadratic exchange, which is responsible for the above degeneracy lifting
Q-operators for the open Heisenberg spin chain
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Rouven Frassek
2015-12-01
Full Text Available We construct Q-operators for the open spin-12 XXX Heisenberg spin chain with diagonal boundary matrices. The Q-operators are defined as traces over an infinite-dimensional auxiliary space involving novel types of reflection operators derived from the boundary Yang–Baxter equation. We argue that the Q-operators defined in this way are polynomials in the spectral parameter and show that they commute with transfer matrix. Finally, we prove that the Q-operators satisfy Baxter's TQ-equation and derive the explicit form of their eigenvalues in terms of the Bethe roots.
Directory of Open Access Journals (Sweden)
Andhika Putra Cahyarifian
2013-09-01
Full Text Available Data penjualan pada perusahaan manufaktur selalu bertambah setiap hari seiring dengan terjadinya transaksi yang dilakukan pelanggan. Hal ini perlu didukung dengan adanya pengelolaan data yang bisa digunakan untuk mengambil keputusan. Selama ini agen PT. XYZ belum mempunyai sistem yang terintegrasi di Surabaya untuk menggunakan seluruh data yang dimilikinya untuk proses pengambilan keputusan. Penulis melakukan pengerjaan penelitian dengan membuat sebuah data warehouse yang digunakan untuk mengelola data dalam jumlah besar, dalam studi kasus ini adalah data penjualan harian agen PT.XYZ. Selain itu pemanfaatan pengambilan keputusan dari data penjualan yang terhitung besar ini juga perlu dilakukan. Salah satu caranya adalah dengan melakukan penggalian asosiasi untuk memberikan rekomendasi produk cross-selling. Metode yang digunakan dalam pengerjaan penelitian ini adalah metode association rule mining, dengan metode ini akan ditemukan sebuah pola dari data transaksi penjualan dari periode sebelumnya mengenai hubungan keterkaitan antar variabel sehingga diketahui kecenderungan produk yang akan dibeli oleh pelanggan bersamaan dengan produk tertentu. Hasil yang diharapkan dari penelitian ini adalah rekomendasi produk cross-selling dari proses penggalian asosiasi terhadap data penjualan agen PT. XYZ. Dan dapat membantu agen PT. XYZ dalam melakukan pengelolaan data dan pengambilan keputusan.
Heisenberg Groups as Platform for the AAG key-exchange protocol
Kahrobaei, Delaram; Lam, Ha T.
2014-01-01
Garber, Kahrobaei, and Lam studied polycyclic groups generated by number field as platform for the AAG key-exchange protocol. In this paper, we discuss the use of a different kind of polycyclic groups, Heisenberg groups, as a platform group for AAG by submitting Heisenberg groups to one of AAG's major attacks, the length-based attack.
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Hendri Wijaya
2017-09-01
Full Text Available The competition of the banking industry requires Islamic bank to provide a great services to its customers. Service quality is one of the critical points for the banking industry. Good quality services will create customer satisfaction and encourage customer loyalty. The purpose of this research is to analyze the factors that affect customer satisfaction and loyalty of Islamic bank. This research uses the concept of Banking Service Quality (BSQ which is consisting six dimensions: effectiveness and assurance, access, price, service portfolio, reliability, and tangible. BSQ concept is later developed into the Islamic Banking Service Quality by adding a dimension that is Sharia compliance. Thus forming seven dimensions in measuring customer satisfaction of Islamic banks. The research method using Structural Equation Modeling (SEM, respondents are customers of Bank Syariah xyz, sampling technique used is convenience sampling with 160 persons of sample size. The results showed that only four dimensions of price, service portfolio, reliabililty, and tangible has positive effect on customer satisfaction, and customer satisfaction has positive influence on customer loyalty. While the three other dimensions have no effect on customer satisfaction.Keywords: Islamic bank, service quality, SEM, customer satisfaction, customer loyaltyAbstrak: Persaingan yang ketat industri perbankan menuntut bank syariah harus mampu menyediakan layanan yang berkualitas bagi para nasabahnya. Kualitas layanan menjadi salah satu poin kritis bagi industri perbankan yang bergerak di sektor jasa. Kualitas layanan yang baik akan menciptakan kepuasan nasabah dan mendorong loyalitas nasabah. Tujuan dari penelitian ini adalah untuk menganalisis faktor-faktor yang memengaruhi kepuasan dan loyalitas nasabah bank syariah. Pengukuran kepuasan nasabah dalam penelitian ini menggunakan konsep Banking Service Quality (BSQ yang terdiri dari enam dimensi yaitu effectiveness and assurance
Heisenberg's war. The secret history of the German bomb
International Nuclear Information System (INIS)
Powers, T.
1993-01-01
The history of Second World War Germany's 'Uranium Project', which often is referred to as the 'myth of the German atomic bomb', has been attracting the mind's of secret service men, futurologists, historians and journalists since after the end of the war it has become possible to lift the veil of secrecy. Powers book adds another one to the many investigations published since them. His approach to the piece of history starts with Heisenberg's visit to the U.S.A. in summer 1939, describes the plans of the German Heereswaffenamt pursued with the Uranium Project, and their counterpart on the side of the Allied Forces where German scientists, as immigrants in England and in the U.S.A., were doing their best to launch research for the development of an atomic bomb. The end of this 'competition' is marked by the internment of the ten German scientists and bomb specialists in Fall Hall. The leading story of the book centers on the small group of scientists around Heisenberg, who cleverly 'torpedoed' the development of the German atomic bomb in the years from 1939 until 1944. (HP) [de
Linearized pseudo-Einstein equations on the Heisenberg group
Barletta, Elisabetta; Dragomir, Sorin; Jacobowitz, Howard
2017-02-01
We study the pseudo-Einstein equation R11bar = 0 on the Heisenberg group H1 = C × R. We consider first order perturbations θɛ =θ0 + ɛ θ and linearize the pseudo-Einstein equation about θ0 (the canonical Tanaka-Webster flat contact form on H1 thought of as a strictly pseudoconvex CR manifold). If θ =e2uθ0 the linearized pseudo-Einstein equation is Δb u - 4 | Lu|2 = 0 where Δb is the sublaplacian of (H1 ,θ0) and L bar is the Lewy operator. We solve the linearized pseudo-Einstein equation on a bounded domain Ω ⊂H1 by applying subelliptic theory i.e. existence and regularity results for weak subelliptic harmonic maps. We determine a solution u to the linearized pseudo-Einstein equation, possessing Heisenberg spherical symmetry, and such that u(x) → - ∞ as | x | → + ∞.
Implementation of lean manufacturing for frozen fish process at PT. XYZ
Setiyawan, D. T.; Pertiwijaya, H. R.; Effendi, U.
2018-03-01
PT. XYZ is a company specialized in the processing of fishery products particularly in frozen fish fillet. The purpose of this research was to identify the type of waste and determine the recommendations of minimizing waste Lean manufacturing approach was used in the identification of waste by describing the Value Stream Mapping (VSM) and selecting tools in the Value Stream Analysis Tools (VALSAT). The results of this research showed that the highest waste that generated was the defect of leak packaging on fillet products with an average of 1.21%. In addition to defect, other insufficiencies were found such as: unnecessary motion, unnecessary overhead, and waiting time. Recommendations for improvements that given include reduction of time at several stages of the process, making production schedules, and conducting regular machine maintenance. VSM analysis shows reduced lead time of 582.04 minutes to 572.01 minutes.
MANAJEMEN RISIKO KEAMANAN SISTEM INFORMASI MENGGUNAKAN METODE FMEA DAN ISO 27001 PADA ORGANISASI XYZ
Directory of Open Access Journals (Sweden)
Raden Budiarto
2017-07-01
Full Text Available Sekalipun sudah populer di bidang teknik industri, metode Failure Mode & Effect Analysis FMEA masih sangat jarang dilaporkan penelitiannya terhadap objek sistem informasi. Hal ini menarik untuk dieksplorasi lebih lanjut pemanfaatannya pada sistem informasi. Variabel yang diukur pada penelitian ini adalah occurrence (frekuensi kejadian, severity (dampak dan detection (pencegahan. Data penelitian diambil terutama berdasarkan dari hasil pengamatan langsung. Penelitian ini mencakup perlindungan terhadap aset informasi di lingkungan Organisasi XYZ dengan melakukan penilaian risiko keamanan informasi. Penilaian tersebut dilakukan dengan menggunakan metode (FMEA. Pada penelitian ini juga menggunakan kerangka kerja ISO 27001 untuk melengkapi daftar rekomendasi aksi penanggulangan mode kegagalan. Hasil dari penelitian ini yaitu berupa laporan hasil pengelolaan manajemen risiko yang berisikan daftar prioritas analisis risiko yang disertai akar sebab permasalahan dan pengendalian risiko sesuai dengan standar ISO 27001. Hasil dari studi kasus telah membuktikan penerapan standar ISO 27001 berimbas terhadap penurunan tingkat kerawanan sebesar 30%.
Directory of Open Access Journals (Sweden)
Jonny Lin
2015-05-01
Full Text Available PT XYZ has faced a problem related to its plastik material ordering system in which its quantity purchase order calculation result was so different with its manual calculation that its material logictic staff was needed to make a proper correction. Therefore, this research was taken in order to help the staff to analyze its root cause so that the proper improvement could be taken and the quantity purchase order calculation will be equal to its manual calculation. By deploying Kepner-Tregoe problem solving, the staff found that the difference was due to miss-managed algorthim of the system because the quantity purchase order that is still open was not considered in the calculation and after proper improvement was taken, then the quantity purchase order calculation is equal to the manual calculation.
Program to solve the multigroup discrete ordinates transport equation in (x,y,z) geometry
International Nuclear Information System (INIS)
Lathrop, K.D.
1976-04-01
Numerical formulations and programming algorithms are given for the THREETRAN computer program which solves the discrete ordinates, multigroup transport equation in (x,y,z) geometry. An efficient, flexible, and general data-handling strategy is derived to make use of three hierarchies of storage: small core memory, large core memory, and disk file. Data management, input instructions, and sample problem output are described. A six-group, S 4 , 18 502 mesh point, 2 800 zone, k/sub eff/ calculation of the ZPPR-4 critical assembly required 144 min of CDC-7600 time to execute to a convergence tolerance of 5 x 10 -4 and gave results in good qualitative agreement with experiment and other calculations. 6 references
Directory of Open Access Journals (Sweden)
Darjat Sudrajat
2012-05-01
Full Text Available A company is a market-oriented when the culture of value creation superior customer systematically and comprehensively implemented on company concerned. Value can be defined as the ratio of benefit to cost, where customers expect a rate of return equal or exceed the costs they incurred to obtain the products they bought. From the case studies conducted on PT XYZ, then, in getting the project tender delivery of goods geophysical equipment for the Brunei Loon project, it has been implemented value selling creation, which includes three main components, ie customer portraits, the proposed value, and benefits to customers or total value of ownership. Overall, the efficiency given value is about 20% compared to its closest competitor, the safety shipping and on time, as well as the positive benefits of the profit margin, cash flow, return on investment, brand equity, market share and customers.
Productivity improvement in the production line with lean manufacturing approach: case study PT. XYZ
Directory of Open Access Journals (Sweden)
diah Halimatussa’
2018-01-01
Full Text Available The increaseing productivity is one of the competitive strategies that can be applied in a company in order to survive in an intense competitive presure. PT. XYZ is a textile industry manufacturing golf gloves and caddy bag. Every day, the company has a production target of 600 pieces per line. However, the desired target is not achieved that it will affect the delay in delivery of products to customers. In this research, a case study on implementing value stream mapping and Kaizen as the lean manufacturing concept is reported. The purpose of this study is to map the current production line, analyse and design the future value stream mapping by eliminating waste occured. It is obtained a lead time reduction as much as 440.4 seconds through eliminating 17 non-value added activities. Then, the output can be increased up to 21% which is equal to 502 pieces.
Directory of Open Access Journals (Sweden)
Evy Ekawati
2014-06-01
Full Text Available The increasing complexity of processes and operational functions cause arises the need for an integrated information system across all functional areas to reach the highest point of effectiveness and efficiency, and relying on the information in making decisions, ie ERP (Enterprise Resource Planning. The objective of writing this journal is to analyze and determine a SAP system development strategy planning at Human Capital and Legal of Education Institution XYZ. In collecting data, the author collected the datas by making an interview with the sources, data observation, and SAP system exploration. Current architecture datas that were collected and anylized to design the planning strategy in developing system architecture. The conclusion of this journal writing is that planning with some methodologies could maximize the using of IS or IT in an organization and can achieve its goals.
Incommensurate correlations in the anisotropic triangular Heisenberg lattice
Weichselbaum, Andreas; White, Steven R.
2011-12-01
We study the anisotropic spin-1/2 antiferromagnetic triangular Heisenberg lattice in two dimensions, seen as a set of chains with couplings J (J') along (in-between) chains, respectively. Our focus is on the incommensurate correlation that emerges in this system in a wide parameter range due to the intrinsic frustration of the spins. We study this system with traditional density matrix renormalization group using cylindrical boundary conditions to least constrain possible incommensurate order. Despite that the limit of essentially decoupled chains J'/J≲0.5 is not very accessible numerically, it appears that the spin-spin correlations remain incommensurate for any finite 0JC', where JC'/J>1. The incommensurate wave vector qJ, however, approaches the commensurate value corresponding to the antiferromagnetic correlation of a single chain very rapidly with decreasing J'/J, roughly as qJ˜π-c1(J'/J)ne-c2J/J'.
Analytical and numerical performance models of a Heisenberg Vortex Tube
Bunge, C. D.; Cavender, K. A.; Matveev, K. I.; Leachman, J. W.
2017-12-01
Analytical and numerical investigations of a Heisenberg Vortex Tube (HVT) are performed to estimate the cooling potential with cryogenic hydrogen. The Ranque-Hilsch Vortex Tube (RHVT) is a device that tangentially injects a compressed fluid stream into a cylindrical geometry to promote enthalpy streaming and temperature separation between inner and outer flows. The HVT is the result of lining the inside of a RHVT with a hydrogen catalyst. This is the first concept to utilize the endothermic heat of para-orthohydrogen conversion to aid primary cooling. A review of 1st order vortex tube models available in the literature is presented and adapted to accommodate cryogenic hydrogen properties. These first order model predictions are compared with 2-D axisymmetric Computational Fluid Dynamics (CFD) simulations.
Spin polaron in the J1-J2 Heisenberg model
Hamad, I. J.; Trumper, A. E.; Feiguin, A. E.; Manuel, L. O.
2008-01-01
We have studied the validity of the spin-polaron picture in the frustrated J1-J2 Heisenberg model. For this purpose, we have computed the hole spectral functions for the Néel, collinear, and disordered phases of this model by means of the self-consistent Born approximation and Lanczos exact diagonalization on finite-size clusters. We have found that the spin-polaron quasiparticle excitation is always well defined for the magnetically ordered Néel and collinear phases, even in the vicinity of the magnetic quantum critical points, where the local magnetization vanishes. As a general feature, the effect of frustration is to increase the amplitude of the multimagnon states that build up the spin-polaron wave function, leading to the reduction of the quasiparticle coherence. Based on Lanczos results, we discuss the validity of the spin-polaron picture in the disordered phase.
Quantum spin transistor with a Heisenberg spin chain
Marchukov, O. V.; Volosniev, A. G.; Valiente, M.; Petrosyan, D.; Zinner, N. T.
2016-01-01
Spin chains are paradigmatic systems for the studies of quantum phases and phase transitions, and for quantum information applications, including quantum computation and short-distance quantum communication. Here we propose and analyse a scheme for conditional state transfer in a Heisenberg XXZ spin chain which realizes a quantum spin transistor. In our scheme, the absence or presence of a control spin excitation in the central gate part of the spin chain results in either perfect transfer of an arbitrary state of a target spin between the weakly coupled input and output ports, or its complete blockade at the input port. We also discuss a possible proof-of-concept realization of the corresponding spin chain with a one-dimensional ensemble of cold atoms with strong contact interactions. Our scheme is generally applicable to various implementations of tunable spin chains, and it paves the way for the realization of integrated quantum logic elements. PMID:27721438
Classical ground states of symmetric Heisenberg spin systems
International Nuclear Information System (INIS)
Schmidt, Heinz-Juergen; Luban, Marshall
2003-01-01
We investigate the ground states of classical Heisenberg spin systems which have point group symmetry. Examples are the regular polygons (spin rings) and the seven quasi-regular polyhedra including the five Platonic solids. For these examples, ground states with special properties, e.g. coplanarity or symmetry, can be completely enumerated using group-theoretical methods. For systems having coplanar (anti-) ground states with vanishing total spin we also calculate the smallest and largest energies of all states having a given total spin S. We find that these extremal energies depend quadratically on S and prove that, under certain assumptions, this happens only for systems with coplanar S = 0 ground states. For general systems the corresponding parabolas represent lower and upper bounds for the energy values. This provides strong support and clarifies the conditions for the so-called rotational band structure hypothesis which has been numerically established for many quantum spin systems
Classical ground states of symmetric Heisenberg spin systems
Schmidt, H J
2003-01-01
We investigate the ground states of classical Heisenberg spin systems which have point group symmetry. Examples are the regular polygons (spin rings) and the seven quasi-regular polyhedra including the five Platonic solids. For these examples, ground states with special properties, e.g. coplanarity or symmetry, can be completely enumerated using group-theoretical methods. For systems having coplanar (anti-) ground states with vanishing total spin we also calculate the smallest and largest energies of all states having a given total spin S. We find that these extremal energies depend quadratically on S and prove that, under certain assumptions, this happens only for systems with coplanar S = 0 ground states. For general systems the corresponding parabolas represent lower and upper bounds for the energy values. This provides strong support and clarifies the conditions for the so-called rotational band structure hypothesis which has been numerically established for many quantum spin systems.
Anomalous Tunneling of Spin Wave in Heisenberg Ferromagnet
Kato, Yusuke; Watabe, Shohei; Ohashi, Yoji
2012-12-01
The ferromagnetic spin wave (FSW) in classical Heisenberg chain exhibits the perfect transmission in the long-wavelength limit in the transmission-reflection problem with an inhomogeneity of exchange integral. In the presence of local magnetic field, on the other hand, FSW undergoes the perfect reflection in the long-wavelength limit. This difference in the long-wavelength limit is attributed to the symmetry property of the scatterers; it is crucial whether the potential preserves or breaks the spin rotation symmetry. Our result implies that the anomalous tunneling (i.e., perfect transmission in the low-energy limit) found both in scalar and spinor BECs is not specific to gapless modes in superfluids but is a common property shared with generic Nambu-Goldstone modes in the presence of a symmetry-preserving potential scatterer.
Anomalous Tunneling of Spin Wave in Heisenberg Ferromagnet
International Nuclear Information System (INIS)
Kato, Yusuke; Watabe, Shohei; Ohashi, Yoji
2012-01-01
The ferromagnetic spin wave (FSW) in classical Heisenberg chain exhibits the perfect transmission in the long-wavelength limit in the transmission-reflection problem with an inhomogeneity of exchange integral. In the presence of local magnetic field, on the other hand, FSW undergoes the perfect reflection in the long-wavelength limit. This difference in the long-wavelength limit is attributed to the symmetry property of the scatterers; it is crucial whether the potential preserves or breaks the spin rotation symmetry. Our result implies that the anomalous tunneling (i.e., perfect transmission in the low-energy limit) found both in scalar and spinor BECs is not specific to gapless modes in superfluids but is a common property shared with generic Nambu-Goldstone modes in the presence of a symmetry-preserving potential scatterer.
Computational Fluid Dynamics (CFD) simulations of a Heisenberg Vortex Tube
Bunge, Carl; Sitaraman, Hariswaran; Leachman, Jake
2017-11-01
A 3D Computational Fluid Dynamics (CFD) simulation of a Heisenberg Vortex Tube (HVT) is performed to estimate cooling potential with cryogenic hydrogen. The main mechanism driving operation of the vortex tube is the use of fluid power for enthalpy streaming in a highly turbulent swirl in a dual-outlet tube. This enthalpy streaming creates a temperature separation between the outer and inner regions of the flow. Use of a catalyst on the peripheral wall of the centrifuge enables endothermic conversion of para-ortho hydrogen to aid primary cooling. A κ- ɛ turbulence model is used with a cryogenic, non-ideal equation of state, and para-orthohydrogen species evolution. The simulations are validated with experiments and strategies for parametric optimization of this device are presented.
Metamagnetic phase transition of the antiferromagnetic Heisenberg icosahedron.
Schröder, Christian; Schmidt, Heinz-Jürgen; Schnack, Jürgen; Luban, Marshall
2005-05-27
The observation of hysteresis effects in single molecule magnets like Mn12-acetate has initiated ideas of future applications in storage technology. The appearance of a hysteresis loop in such compounds is an outcome of their magnetic anisotropy. In this Letter we report that magnetic hysteresis occurs in a spin system without any anisotropy, specifically where spins mounted on the vertices of an icosahedron are coupled by antiferromagnetic isotropic nearest-neighbor Heisenberg interaction giving rise to geometric frustration. At T = 0 this system undergoes a first-order metamagnetic phase transition at a critical field Bc between two distinct families of ground state configurations. The metastable phase of the system is characterized by a temperature and field dependent survival probability distribution.
Evolution of topological features in finite antiferromagnetic Heisenberg chains
International Nuclear Information System (INIS)
Chen Changfeng
2003-01-01
We examine the behavior of nonlocal topological order in finite antiferromagnetic Heisenberg chains using the density matrix renormalization group techniques. We find that chains with even and odd site parity show very different behavior in the topological string order parameter, reflecting interesting interplay of the intrinsic magnetic correlation and the topological term in the chains. Analysis of the calculated string order parameter as a function of the chain length and the topological angle indicates that S=1/2 and S=1 chains show special behavior while all S>1 chains have similar topological structure. This result supports an earlier conjecture on the classification of quantum spin chains based on an analysis of their phase diagrams. Implications of the topological behavior in finite quantum spin chains are discussed
Demonstrating Heisenberg-limited unambiguous phase estimation without adaptive measurements
International Nuclear Information System (INIS)
Higgins, B L; Wiseman, H M; Pryde, G J; Berry, D W; Bartlett, S D; Mitchell, M W
2009-01-01
We derive, and experimentally demonstrate, an interferometric scheme for unambiguous phase estimation with precision scaling at the Heisenberg limit that does not require adaptive measurements. That is, with no prior knowledge of the phase, we can obtain an estimate of the phase with a standard deviation that is only a small constant factor larger than the minimum physically allowed value. Our scheme resolves the phase ambiguity that exists when multiple passes through a phase shift, or NOON states, are used to obtain improved phase resolution. Like a recently introduced adaptive technique (Higgins et al 2007 Nature 450 393), our experiment uses multiple applications of the phase shift on single photons. By not requiring adaptive measurements, but rather using a predetermined measurement sequence, the present scheme is both conceptually simpler and significantly easier to implement. Additionally, we demonstrate a simplified adaptive scheme that also surpasses the standard quantum limit for single passes.
Anti-ferromagnetic Heisenberg model on bilayer honeycomb
International Nuclear Information System (INIS)
Shoja, M.; Shahbazi, F.
2012-01-01
Recent experiment on spin-3/2 bilayer honeycomb lattice antiferromagnet Bi 3 Mn 4 O 12 (NO 3 ) shows a spin liquid behavior down to very low temperatures. This behavior can be ascribed to the frustration effect due to competitions between first and second nearest neighbour's antiferromagnet interaction. Motivated by the experiment, we study J 1 -J 2 Antiferromagnet Heisenberg model, using Mean field Theory. This calculation shows highly degenerate ground state. We also calculate the effect of second nearest neighbor through z direction and show these neighbors also increase frustration in these systems. Because of these degenerate ground state in these systems, spins can't find any ground state to be freeze in low temperatures. This behavior shows a novel spin liquid state down to very low temperatures.
Anisotropic Heisenberg model for a semi-infinite crystal
International Nuclear Information System (INIS)
Queiroz, C.A.
1985-11-01
A semi-infinite Heisenberg model with exchange interactions between nearest and next-nearest neighbors in a simple cubic lattice. The free surface from the other layers of magnetic ions, by choosing a single ion uniaxial anisotropy in the surface (Ds) different from the anisotropy in the other layers (D). Using the Green function formalism, the behavior of magnetization as a function of the temperature for each layer, as well as the spectrum localized magnons for several values of ratio Ds/D for surface magnetization. Above this critical ratio, a ferromagnetic surface layer is obtained white the other layers are already in the paramagnetic phase. In this situation the critical temperature of surface becomes larger than the critical temperature of the bulk. (Author) [pt
Unified molecular field theory for collinear and noncollinear Heisenberg antiferromagnets
Johnston, David C.
2015-02-01
A unified molecular field theory (MFT) is presented that applies to both collinear and planar noncollinear Heisenberg antiferromagnets (AFs) on the same footing. The spins in the system are assumed to be identical and crystallographically equivalent. This formulation allows calculations of the anisotropic magnetic susceptibility χ versus temperature T below the AF ordering temperature TN to be carried out for arbitrary Heisenberg exchange interactions Ji j between arbitrary neighbors j of a given spin i without recourse to magnetic sublattices. The Weiss temperature θp in the Curie-Weiss law is written in terms of the Ji j values and TN in terms of the Ji j values and an assumed AF structure. Other magnetic and thermal properties are then expressed in terms of quantities easily accessible from experiment as laws of corresponding states for a given spin S . For collinear ordering these properties are the reduced temperature t =T /TN , the ratio f =θp/TN , and S . For planar noncollinear helical or cycloidal ordering, an additional parameter is the wave vector of the helix or cycloid. The MFT is also applicable to AFs with other AF structures. The MFT predicts that χ (T ≤TN) of noncollinear 120∘ spin structures on triangular lattices is isotropic and independent of S and T and thus clarifies the origin of this universally observed behavior. The high-field magnetization and heat capacity for fields applied perpendicular to the ordering axis (collinear AFs) and ordering plane (planar noncollinear AFs) are also calculated and expressed for both types of AF structures as laws of corresponding states for a given S , and the reduced perpendicular field versus reduced temperature phase diagram is constructed.
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Tanty Oktavia
2011-12-01
Full Text Available Running the business process of labor supply is not easy since it involves several parties, and n supported by elements of the documents obtained from internal and external parties. PT XYZ as a company dealing with labor supply service to foreign countries has not had any competent information systems in supporting its business processes. Therefore, this research is expected to produce a draft of information system and database applications that can support the administrative activities of labor supply of the company. The research used both analysis and design methods. Analytical method includes survey of the current system done by observation, interviews, identification of the information needs of the survey results and identification of system requirements. The design method consists of designing a model system using UML notation, designing databases and user interfaces for supporting applications. The information system applications resulted in this research can be a competitive advantage in marketing their employment services and improve business processes of PT XYZ.
Directory of Open Access Journals (Sweden)
Sepsugiarto Sepsugiarto
2011-12-01
Full Text Available Datawarehouse as a business decision support tool for sales data analysis functions to assist the sales department in making daily decisions. PT XYZ often experiences problems in analyzing its sales data, such as can not identify the highest sales areas and the total highest number of sales. The purpose of this study is to analyze and design a decision support tool which is appropriate to the needs of the sales of PT.XYZ. The design of systems uses object-oriented approach while database design uses data warehouse method. Any result obtained from this study is a design a data warehouse that can be used to assist the sales department to create sales decisions everyday. The designed decision-making system based on data warehouse can help the sales department in their daily activities.
Aman Mustika; Rina Oktaviani; Sukardi Sukardi
2017-01-01
Biodiesel is considered as one of the alternative eco-friendly fuels. Besides, the government also issued policy related to biodiesel that is CPO Supporting Fund (CSF) Policy. The aim of the research is to identify Business model canvas (BMC) biodiesel industry in PT XYZ and to know the strategies to develop business from biodiesel industry in line with the CPO supporting fund policy. The analysis tool used in this research is BMC, SWOT and Quantitative Strategic Planning Matrix (QSPM). The r...
Directory of Open Access Journals (Sweden)
Rochman Marota
2015-07-01
Full Text Available This research aimed to answer the questions of sustainability of palm oil processing PT XYZ in the economic, social, environmental and technology with the design and implementation of Material Flow Cost Accounting (MFCA. MFCA provides open information about the classification of production costs, with special attention to the cost of material loss and production waste. The goal is efficiency and effectiveness of production cost which can increase the performance of the production process as well as providing an influence on the value of corporate sustainability. The method used in this research was a mixture of qualitative and quantitative method. Measuring tool used multiple regression analysis to measure the significance of independent variables on the dependent variables. As additional analyses used Multidimensional Scaling (MDS method with rapMFCA techniques and Analytical Hierarchy Process (AHP method with a pairwise comparison technique for assessed corporate sustainability indexes for every dimension and weight combined. The analysis showed that the MFCA provides significant effect as the results of the F test, t test and probability test. The results obtained with this technique showed that the value of sustainability index after merging weight is 85,33 and is in the category of highly sustainable. From these results the performance formulation formulated suggestions for maintaining the stability of the production process of corporate sustainability indexes.Keywords: corporate sustainability, efficiency and effectiveness of production cost, material flow cost accounting, production process performancABSTRAKPenelitian ini berusaha menjawab permasalahan keberlanjutan perusahaan pengolahan kelapa sawit PT XYZ dalam dimensi ekonomi, sosial, lingkungan dan teknologi dengan perancangan dan penerapan Material Flow Cost Accounting (MFCA. MFCA memberikan informasi terbuka tentang klasifikasi biaya produksi, dengan perhatian khusus kepada
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Arief Anwar Shodiq
2012-09-01
Full Text Available Setiap lembaga atau instansi memerlukan teknologi informasi (TI untuk mendukung banyak aktivitas dalam menangani proses bisnisnya. Untuk itu, dibutuhkan pengelolaan teknologi informasi yang ideal dan pembentukan struktur organisasi yang relevan dan dapat menjawab kebutuhan akan kelancaran proses bisnisnya. Tidak terkecuali pada Dinas XYZ sebagai lembaga pemerintahan yang bertugas sebagai pengelola pendidikan dan kebudayaan di tingkat provinsi. Dibutuhkan sebuah struktur organisasi pengelola teknologi informasi yang selaras dengan Rencana Jangka Panjang Instansi untuk mendukung tujuan bisnisnya. Dan ketika perencanaan strategis ini diperbaharui, struktur organisasi juga dituntut untuk diperbaharui mengikuti perubahan kebijakan yang baru. Untuk itu, diperlukan analisis komprehensif mengenai perancangan struktur organisasi yang ideal bagi Dinas XYZ ini, yang meliputi studi pendahuluan yang mengkaji literatur dan kondisi kekinian Dinas XYZ, identifikasi Business Goals, identifikasi IT Goals dan IT Process, penentuan struktur organisasi pengelola TI masa depan beserta tanggung jawab masing-masing bagian, dan analisis gap mengenai kondisi saat ini dan kebutuhan TI masa depan, yang semua itu disesuaikan dengan framework COBIT 4.1 sebagai acuan best practice bagi pengelolaan teknologi informasi.
Griffiths, Bradley Joseph
New supply chain management methods using radio frequency identification (RFID) and global positioning system (GPS) technology are quickly being adopted by companies as various inventory management benefits are being realized. For example, companies such as Nippon Yusen Kaisha (NYK) Logistics use the technology coupled with geospatial support systems for distributors to quickly find and manage freight containers. Traditional supply chain management methods require pen-to-paper reporting, searching inventory on foot, and human data entry. Some companies that prioritize supply chain management have not adopted the new technology, because they may feel that their traditional methods save the company expenses. This thesis serves as a pilot study that examines how information technology (IT) utilizing RFID and GPS technology can serve to increase workplace productivity, decrease human labor associated with inventorying, plus be used for spatial analysis by management. This pilot study represents the first attempt to couple RFID technology with Geographic Information Systems (GIS) in supply chain management efforts to analyze and locate mobile assets by exploring costs and benefits of implementation plus how the technology can be employed. This pilot study identified a candidate to implement a new inventory management method as XYZ Logistics, Inc. XYZ Logistics, Inc. is a fictitious company but represents a factual corporation. The name has been changed to provide the company with anonymity and to not disclose confidential business information. XYZ Logistics, Inc., is a nation-wide company that specializes in providing space solutions for customers including portable offices, storage containers, and customizable buildings.
You err, Einstein.. Newton, Einstein, Heisenberg, and Feynman discuss quantum physics
International Nuclear Information System (INIS)
Fritzsch, Harald
2008-01-01
Harald Fritzsch and his star physicists Einstein, Heisenberg, and Feynman explain the central concept of nowadays physics, quantum mechanics, without it nothing goes in modern world. And the great Isaac newton puts the questions, which all would put
Uncertainty Einstein, Heisenberg, Bohr, and the struggle for the soul of science
Lindley, David
2007-01-01
The uncertainty in this delightful book refers to Heisenberg's Uncertainty Principle, an idea first postulated in 1927 by physicist Werner Heisenberg in his attempt to make sense out of the developing field of quantum mechanics. As Lindley so well explains it, the concept of uncertainty shook the philosophical underpinnings of science. It was Heisenberg's work that, to a great extent, kept Einstein from accepting quantum mechanics as a full explanation for physical reality. Similarly, it was the Uncertainty Principle that demonstrated the limits of scientific investigation: if Heisenberg is correct there are some aspects of the physical universe that are to remain beyond the reach of scientists. As he has done expertly in books like Boltzmann's Atom, Lindley brings to life a critical period in the history of science, explaining complex issues to the general reader, presenting the major players in an engaging fashion, delving into the process of scientific discovery and discussing the interaction between scien...
Condensation of vortices and disorder parameter in 3d Heisenberg model
Di Giacomo, A.; Martelli, D.; Paffuti, G.
1998-01-01
The 3d Heisenberg model is studied from a dual point of view. It is shown that the disordered phase corresponds to condensation of vortices in the vacuum, and the critical indices are computed from the corresponding disorder parameter.
The representation of the Heisenberg-Euler Lagrangian by means of special functions
International Nuclear Information System (INIS)
Mielniczuk, W.J.
1982-01-01
A representation of the real part of the Heisenberg-Euler Lagrangian density in quantum electrodynamics is obtained by means of special functions. It is shown that this representation is very convenient for numerical calculations of the real part of the Heisenberg-Euler Lagrangian density and its use for calculations of a quantum electrodynamical field energy density in the absence of real charges and for calculations of polarisation and magnetisation of the vacuum, is examined. (author)
At the Limits of Criticality-Based Quantum Metrology: Apparent Super-Heisenberg Scaling Revisited
Rams, Marek M.; Sierant, Piotr; Dutta, Omyoti; Horodecki, Paweł; Zakrzewski, Jakub
2018-04-01
We address the question of whether the super-Heisenberg scaling for quantum estimation is indeed realizable. We unify the results of two approaches. In the first one, the original system is compared with its copy rotated by the parameter-dependent dynamics. If the parameter is coupled to the one-body part of the Hamiltonian, the precision of its estimation is known to scale at most as N-1 (Heisenberg scaling) in terms of the number of elementary subsystems used N . The second approach compares the overlap between the ground states of the parameter-dependent Hamiltonian in critical systems, often leading to an apparent super-Heisenberg scaling. However, we point out that if one takes into account the scaling of time needed to perform the necessary operations, i.e., ensuring adiabaticity of the evolution, the Heisenberg limit given by the rotation scenario is recovered. We illustrate the general theory on a ferromagnetic Heisenberg spin chain example and show that it exhibits such super-Heisenberg scaling of ground-state fidelity around the critical value of the parameter (magnetic field) governing the one-body part of the Hamiltonian. Even an elementary estimator represented by a single-site magnetization already outperforms the Heisenberg behavior providing the N-1.5 scaling. In this case, Fisher information sets the ultimate scaling as N-1.75, which can be saturated by measuring magnetization on all sites simultaneously. We discuss universal scaling predictions of the estimation precision offered by such observables, both at zero and finite temperatures, and support them with numerical simulations in the model. We provide an experimental proposal of realization of the considered model via mapping the system to ultracold bosons in a periodically shaken optical lattice. We explicitly derive that the Heisenberg limit is recovered when the time needed for preparation of quantum states involved is taken into account.
Werner Heisenberg and Carl Friedrich Freiherr von Weizsäcker: A Fifty-Year Friendship*
Cassidy, David C.
2015-03-01
This paper follows Werner Heisenberg and Carl Friedrich von Weizsäcker during their fifty-year friendship from 1926, when they first met in Copenhagen, to Heisenberg's death in Munich in 1976. The relationship underwent profound changes during that period, as did physics, philosophy, and German society and politics, all of which exerted important influences on their lives, work, and interactions with each other. The nature of these developments and their impact are explored in this paper.
Jonny; Nasution, Januar
2013-06-01
Value stream mapping is a tool which is needed to let the business leader of XYZ Hospital to see what is actually happening in its business process that have caused longer lead time for self-produced medicines in its pharmacy unit. This problem has triggered many complaints filed by patients. After deploying this tool, the team has come up with the fact that in processing the medicine, pharmacy unit does not have any storage and capsule packing tool and this condition has caused many wasting times in its process. Therefore, the team has proposed to the business leader to procure the required tools in order to shorten its process. This research has resulted in shortened lead time from 45 minutes to 30 minutes as required by the government through Indonesian health ministry with increased %VA (valued added activity) or Process Cycle Efficiency (PCE) from 66% to 68% (considered lean because it is upper than required 30%). This result has proved that the process effectiveness has been increase by the improvement.
International Nuclear Information System (INIS)
Jonny; Nasution, Januar
2013-01-01
Value stream mapping is a tool which is needed to let the business leader of XYZ Hospital to see what is actually happening in its business process that have caused longer lead time for self-produced medicines in its pharmacy unit. This problem has triggered many complaints filed by patients. After deploying this tool, the team has come up with the fact that in processing the medicine, pharmacy unit does not have any storage and capsule packing tool and this condition has caused many wasting times in its process. Therefore, the team has proposed to the business leader to procure the required tools in order to shorten its process. This research has resulted in shortened lead time from 45 minutes to 30 minutes as required by the government through Indonesian health ministry with increased %VA (valued added activity) or Process Cycle Efficiency (PCE) from 66% to 68% (considered lean because it is upper than required 30%). This result has proved that the process effectiveness has been increase by the improvement.
Buchari; Tarigan, U.; Ambarita, M. B.
2018-02-01
PT. XYZ is a wood processing company which produce semi-finished wood with production system is make to order. In the production process, it can be seen that the production line is not balanced. The imbalance of the production line is caused by the difference in cycle time between work stations. In addition, there are other issues, namely the existence of material flow pattern is irregular so it resulted in the backtracking and displacement distance away. This study aimed to obtain the allocation of work elements to specific work stations and propose an improvement of the production layout based on the result of improvements in the line balancing. The method used in the balancing is Ranked Positional Weight (RPW) or also known as Helgeson Birnie method. While the methods used in the improvement of the layout is the method of Systematic Layout Planning (SLP). By using Ranked Positional Weight (RPW) obtained increase in line efficiency becomes 84,86% and decreased balance delay becomes 15,14%. Repairing the layout using the method of Systematic Layout Planning (SLP) also give good results with a reduction in path length becomes 133,82 meters from 213,09 meters previously or a decrease of 37.2%.
ANALISIS POSTUR KERJA PADA PT. XYZ MENGGUNAKAN METODE ROSA (RAPID OFFICE STRAIN ASSESSMENT
Directory of Open Access Journals (Sweden)
Rosma Hani Damayanti
2014-06-01
Full Text Available Penggunaan teknologi informasi, dimana komputer sebagai medianya kini semakin meningkat. Frekuensi yang tinggi akan penggunaan komputer yang tidak memperhatikan sisi ergonomi dalam bekerja mengakibatkan adanya resiko yang dirasakan oleh pengguna. PT. XYZ merupakan salah satu perusahaan yang menggunakan komputer sebagai salah satu alat utama dalam bekerja. Pada penggunaannya karyawan pada Departemen Publishing merasakan keluhan pada punggung, pinggang, nyeri bahu, leher dan tangan. Keluhan yang dirasakan oleh pekerja pada Departemen publishing dapat diminimalkan dengan cara mengetahui dan mengidentifikasi postur kerja pada pekerja dalam menggunakan komputer. Identifikasi tersebut digunakan untuk mengetahui kondisi pekerja dan mengetahui penyebab keluhan yang dirasakan oleh pekerja untuk dilakukan perbaikan. Pada penelitian ini dilakukan analisis dengan menggunakan metode ROSA untuk mengurangi adanya keluhan yang dirasakan oleh pekerja pada Departemen publishing. ROSA merupakan salah satu metode pada office ergonomics, dimana penilaiannnya dirancang untuk mengukur resiko yang terkait dengan penggunaan komputer serta untuk menetapkan tingkat tindakan perubahan berdasarkan laporan dari ketidaknyamanan pekerja. Dengan menggunakan metode ROSA, dapat diketahui apakah postur kerja karyawan pada Departemen Publishing pada saat bekerja aman atau berbahaya. Hasil analisis postur kerja menggunakan metode ROSA pada Departemen Publishing menunjukkan bahwa seluruh pekerja yang menjadi sampel memiliki level resiko yang tinggi dan perlu dilakukan perbaikan segera. Perbaikan yang dapat dilakukan untuk mengurangi tingkat resiko yang dirasakan oleh pekerja yaitu dengan perbaikan fasilitas yang digunakan oleh pekerja yang sesuai dengan standar ergonomi, melakukan sosialisasi kepada pekerja tentang pentingnya ergonomi pada dunia kerja, dan sebaiknya pekerja melakukan istirahat atau peregangan otot minimal setiap tiga jam sekali.
ANALISIS POSTUR KERJA PADA PT. XYZ MENGGUNAKAN METODE ROSA (RAPID OFFICE STRAIN ASSESSMENT
Directory of Open Access Journals (Sweden)
Rosma Hani Damayanti
2014-06-01
Full Text Available Penggunaan teknologi informasi, dimana komputer sebagai medianya kini semakin meningkat. Frekuensi yang tinggi akan penggunaan komputer yang tidak memperhatikan sisi ergonomi dalam bekerja mengakibatkan adanya resiko yang dirasakan oleh pengguna. PT. XYZ merupakan salah satu perusahaan yang menggunakan komputer sebagai salah satu alat utama dalam bekerja. Pada penggunaannya karyawan pada Departemen Publishing merasakan keluhan pada punggung, pinggang, nyeri bahu, leher dan tangan. Keluhan yang dirasakan oleh pekerja pada Departemen publishing dapat diminimalkan dengan cara mengetahui dan mengidentifikasi postur kerja pada pekerja dalam menggunakan komputer. Identifikasi tersebut digunakan untuk mengetahui kondisi pekerja dan mengetahui penyebab keluhan yang dirasakan oleh pekerja untuk dilakukan perbaikan. Pada penelitian ini dilakukan analisis dengan menggunakan metode ROSA untuk mengurangi adanya keluhan yang dirasakan oleh pekerja pada Departemen publishing. ROSA merupakan salah satu metode pada office ergonomics, dimana penilaiannnya dirancang untuk mengukur resiko yang terkait dengan penggunaan komputer serta untuk menetapkan tingkat tindakan perubahan berdasarkan laporan dari ketidaknyamanan pekerja. Dengan menggunakan metode ROSA, dapat diketahui apakah postur kerja karyawan pada Departemen Publishing pada saat bekerja aman atau berbahaya. Hasil analisis postur kerja menggunakan metode ROSA pada Departemen Publishing menunjukkan bahwa seluruh pekerja yang menjadi sampel memiliki level resiko yang tinggi dan perlu dilakukan perbaikan segera. Perbaikan yang dapat dilakukan untuk mengurangi tingkat resiko yang dirasakan oleh pekerja yaitu dengan perbaikan fasilitas yang digunakan oleh pekerja yang sesuai dengan standar ergonomi, melakukan sosialisasi kepada pekerja tentang pentingnya ergonomi pada dunia kerja, dan sebaiknya pekerja melakukan istirahat atau peregangan otot minimal setiap tiga jam sekali.
Queueing system analysis of multi server model at XYZ insurance company in Tasikmalaya city
Muhajir, Ahmad; Binatari, Nikenasih
2017-08-01
Queueing theory or waiting line theory is a theory that deals with the queue process from the customer comes, queue to be served, served and left on service facilities. Queue occurs because of a mismatch between the numbers of customers that will be served with the available number of services, as an example at XYZ insurance company in Tasikmalaya. This research aims to determine the characteristics of the queue system which then to optimize the number of server in term of total cost. The result shows that the queue model can be represented by (M/M/4):(GD/∞/∞), where the arrivals are Poisson distributed while the service time is following exponential distribution. The probability of idle customer service is 2,39% of the working time, the average number of customer in the queue is 3 customers, the average number of customer in a system is 6 customers, the average time of a customer spent in the queue is 15,9979 minutes, the average time a customer spends in the system is 34,4141 minutes, and the average number of busy customer servicer is 3 server. The optimized number of customer service is 5 servers, and the operational cost has minimum cost at Rp 4.323.
e-Learning Application for Machine Maintenance Process using Iterative Method in XYZ Company
Nurunisa, Suaidah; Kurniawati, Amelia; Pramuditya Soesanto, Rayinda; Yunan Kurnia Septo Hediyanto, Umar
2016-02-01
XYZ Company is a company based on manufacturing part for airplane, one of the machine that is categorized as key facility in the company is Millac 5H6P. As a key facility, the machines should be assured to work well and in peak condition, therefore, maintenance process is needed periodically. From the data gathering, it is known that there are lack of competency from the maintenance staff to maintain different type of machine which is not assigned by the supervisor, this indicate that knowledge which possessed by maintenance staff are uneven. The purpose of this research is to create knowledge-based e-learning application as a realization from externalization process in knowledge transfer process to maintain the machine. The application feature are adjusted for maintenance purpose using e-learning framework for maintenance process, the content of the application support multimedia for learning purpose. QFD is used in this research to understand the needs from user. The application is built using moodle with iterative method for software development cycle and UML Diagram. The result from this research is e-learning application as sharing knowledge media for maintenance staff in the company. From the test, it is known that the application make maintenance staff easy to understand the competencies.
Directory of Open Access Journals (Sweden)
Sigit Wahono
2017-10-01
Full Text Available PT XYZ is one manufacturing company engaged in the production of animal feed. In the production process sometimes product results does not comply with the requests received by the company. There are many factors which could this problem happened. One of them is less than the maximum engine performance production caused by high downtime on a production machine. To find out how well the performance of a production machine, then it is held a performance assessment by using Overall Throughput Effectiveness (OTE method.Overall Throughput Effectiveness calculations performed on the line pellet machine was obtained 48.97%. This value is still far to the standard value desired by the company which is 70%. For performance improvement can be done by improving the engine damaged and analyzed by using Failure Mode and Effect Analysis (FMEA. From the analysis showed that the failure modes of root dies breaking up with the value of the RPN 224 is a damage that must be repaired immediately because obtaining the highest RPN value compared to other failure modes.
Stapp's quantum dualism: The James/Heisenberg model of consciousness
International Nuclear Information System (INIS)
Noyes, H.P.
1994-01-01
Henry Stapp attempts to resolve the Cartesian dilemma by introducing what the author would characterize as an ontological dualism between mind and matter. His model for mind comes from William James' description of conscious events and for matter from Werner Heisenberg's ontological model for quantum events (wave function collapse). His demonstration of the isomorphism between the two types of events is successful, but in the author's opinion fails to establish a monistic, scientific theory. The author traces Stapp's failure to his adamant rejection of arbitrariness, or 'randomness'. This makes it impossible for him (or for Bohr and Pauli before him) to understand the power of Darwin's explanation of biology, let along the triumphs of modern 'neo-Darwinism'. The author notes that the point at issue is a modern version of the unresolved opposition between Leucippus and Democritus on one side and Epicurus on the other. Stapp's views are contrasted with recent discussions of consciousness by two eminent biologists: Crick and Edelman. They locate the problem firmly in the context of natural selection on the surface of the earth. Their approaches provide a sound basis for further scientific work. The author briefly examines the connection between this scientific (rather than ontological) framework and the new fundamental theory based on bit-strings and the combinatorial hierarchy
Reducing Uncertainty: Implementation of Heisenberg Principle to Measure Company Performance
Directory of Open Access Journals (Sweden)
Anna Svirina
2015-08-01
Full Text Available The paper addresses the problem of uncertainty reduction in estimation of future company performance, which is a result of wide range of enterprise's intangible assets probable efficiency. To reduce this problem, the paper suggests to use quantum economy principles, i.e. implementation of Heisenberg principle to measure efficiency and potential of intangible assets of the company. It is proposed that for intangibles it is not possible to estimate both potential and efficiency at a certain time point. To provide a proof for these thesis, the data on resources potential and efficiency from mid-Russian companies was evaluated within deterministic approach, which did not allow to evaluate probability of achieving certain resource efficiency, and quantum approach, which allowed to estimate the central point around which the probable efficiency of resources in concentrated. Visualization of these approaches was performed by means of LabView software. It was proven that for tangible assets performance estimation a deterministic approach should be used; while for intangible assets the quantum approach allows better quality of future performance prediction. On the basis of these findings we proposed the holistic approach towards estimation of company resource efficiency in order to reduce uncertainty in modeling company performance.
Topological superconductivity in the extended Kitaev-Heisenberg model
Schmidt, Johann; Scherer, Daniel D.; Black-Schaffer, Annica M.
2018-01-01
We study superconducting pairing in the doped Kitaev-Heisenberg model by taking into account the recently proposed symmetric off-diagonal exchange Γ . By performing a mean-field analysis, we classify all possible superconducting phases in terms of symmetry, explicitly taking into account effects of spin-orbit coupling. Solving the resulting gap equations self-consistently, we map out a phase diagram that involves several topologically nontrivial states. For Γ find a competition between a time-reversal symmetry-breaking chiral phase with Chern number ±1 and a time-reversal symmetric nematic phase that breaks the rotational symmetry of the lattice. On the other hand, for Γ ≥0 we find a time-reversal symmetric phase that preserves all the lattice symmetries, thus yielding clearly distinguishable experimental signatures for all superconducting phases. Both of the time-reversal symmetric phases display a transition to a Z2 nontrivial phase at high doping levels. Finally, we also include a symmetry-allowed spin-orbit coupling kinetic energy and show that it destroys a tentative symmetry-protected topological order at lower doping levels. However, it can be used to tune the time-reversal symmetric phases into a Z2 nontrivial phase even at lower doping.
Matched Weyl-Heisenberg expansions of nonstationary environments
International Nuclear Information System (INIS)
Kozek, W.
1996-09-01
This thesis is about various aspects of linear time-varying systems and nonstationary processes (together nonstationary environments). Such nonstationary environments play an important role in modern communication engineering, particularly as models for natural signals or time-varying communication channels. Emphasis is on time-frequency-parametrized representations of nonstationary environments, i.e., time-varying power spectra and time varying transfer functions. Introduction of the generalized Weyl correspondence enables a unified formulation of classical, so far seemingly disparate definitions like Priestley's evolutionary spectrum, the Wigner-Ville spectrum, Zadeh's time-varying transfer function (Kohn-Nirenberg symbol) and the Weyl symbol. Nonstationary Wiener filtering provides an illustrative example for the limited applicability of these time-frequency concepts to a straight forward generalization of frequency domain solutions. We introduce a fundamental classification into underspread/overspread environments based on characterizing the underlying linear operator by the essential support of its spreading function. For underspread environments it is shown that the time-frequency-parametrized representations get essentially definition-independent and can be used in the same manner as the frequency-parametrized representations of stationary environments. Combining the practical efficiency of time-frequency-parametrized representations with the theoretical optimality of a diagonalizing transform leads to window matching criteria for the short-time Fourier transform/ Gabor expansion (discrete/continuous Weyl-Heisenberg expansion) of signals and linear systems. (author)
Directory of Open Access Journals (Sweden)
Annisa Rachmi
2014-09-01
Full Text Available Penggunaan Teknologi Informasi di banyak perusahaan telah menjadi satu hal penting dalam meningkatkan efektifitas dan efisiensi operasional bisnis yang mendukung tercapainya tujuan perusahaan, termasuk juga PT XYZ. Unit fungsional service desk sangat dibutuhkan oleh PT XYZ dalam mendukung operasional TI dan menangani permasalahan yang muncul serta memonitor terkait penggunaan TI yang ada di dalam perusahaan. Adanya kebutuhan PT XYZ untuk menjadikan service desk menjadi unit yang dapat berjalan dengan baik sesuai dengan fungsinya, menunjukkan bahwa perlunya penerapan tata kelola TI untuk mengatur dan mengelola aktivitas service desk. Salah satu tata kelola TI yang dimaksud adalah berupa prosedur kerja. Kerangka kerja Information Technology Infrastructure Library (ITIL merupakan suatu best practice yang bertujuan secara berkelanjutan meningkatkan efisiensi operasional TI. Perancangan dan implementasi service desk berdasarkan kerangka kerja ITIL V3 di PT XYZ diperlukan dalam upaya meningkatkan layanan TI dan mengatasi masalah yang ada saat ini. Pembuatan SOP ini diinisialisasi dengan menggunakan metode analisis gap, proses-proses yang dimuat ke dalam SOP merupakan hasil analisis kesenjangan antara kondisi kekinian service desk PT XYZ dengan kondisi ideal service desk framework ITIL.
STRUKTUR MODAL DAN MODAL KERJA PT XYZ SERTA PENGARUHNYA TERHADAP KINERJA PERUSAHAAN
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Untung Setiono
2017-01-01
Full Text Available n 2012, the electronic payment system transactions reached IDR 104.830 trillion or increase 46,52% from the previous year. PT. XYZ is the pioneer in the electronic payment system Indonesia and still one of the leading companies in electronic payment system interbank, through ATM (Automatic Teller Machine and EDC (Electronic Data Capture in Indonesia. In 2012 the company spent USD 3,4 million on software tandem from a foreign vendor. Therefore it is important to study (1 policy on the modal structure of the company, (2 the working capital policy of the company, (3 the monetary performance relationship of the company based on the 2 policies. The method used to analyze the data is multiple linear regression analysis; this method is used to calculate the relationship between the structure variable of the capital and working capital. The result is; 1 the structure policy on the capital of the company is in accordance with the Pecking Order theory where the company uses their own capital before applying the long term debt to the others, 2 the inefficient policy on the company’s working capital is because most of the active asset is in monthly deposit bonds and even extended the active debt, 3 the relationship between short term debt and liquidity ratio is negative while the total debt (short and long term has a positive correlation with the solvability/leverage ratio of the company. The research recommends the management to decrease the active asset and uses it for long term investment not only for timed deposit.Keywords: ATM, EDC, capital structure, financial performance AbstrakVoulme transaksi dalam menggunakan sistem pembayaran elektronis pada tahun 2012 mencapai Rp104.830 triliun atau meningkat sekitar 46,52% dari tahun sebelumnya. PT XYZ adalah salah satu perusahaan pionir dalam sistem bidang pembayaran elektronis di Indonesia dan tetap menjadi pemain utama dalam sistem pembayaran elektronis antar bank, ATM
Generalization of Spatial Channel Theory to Three-Dimensional x-y-z Transport Computations
Energy Technology Data Exchange (ETDEWEB)
I. K. Abu-Shumays; M. A. Hunter; R. L. Martz; J. M. Risner
2002-03-12
Spatial channel theory, initially introduced in 1977 by M. L. Williams and colleagues at ORNL, is a powerful tool for shield design optimization. It focuses on so called ''contributon'' flux and current of particles (a fraction of the total of neutrons, photons, etc.) which contribute directly or through their progeny to a pre-specified response, such as a detector reading, dose rate, reaction rate, etc., at certain locations of interest. Particles that do not contribute directly or indirectly to the pre-specified response, such as particles that are absorbed or leak out, are ignored. Contributon fluxes and currents are computed based on combined forward and adjoint transport solutions. The initial concepts were considerably improved by Abu-Shumays, Selva, and Shure by introducing steam functions and response flow functions. Plots of such functions provide both qualitative and quantitative information on dominant particle flow paths and identify locations within a shield configuration that are important in contributing to the response of interest. Previous work was restricted to two dimensional (2-D) x-y rectangular and r-z cylindrical geometries. This paper generalizes previous work to three-dimensional x-y-z geometry, since it is now practical to solve realistic 3-D problems with multidimensional transport programs. As in previous work, new analytic expressions are provided for folding spherical harmonics representations of forward and adjoint transport flux solutions. As a result, the main integrals involve in spatial channel theory are computed exactly and more efficiently than by numerical quadrature. The analogy with incompressible fluid flow is also applied to obtain visual qualitative and quantitative measures of important streaming paths that could prove vital for shield design optimization. Illustrative examples are provided. The connection between the current paper and the excellent work completed by M. L. Williams in 1991 is also
The System of Inventory Forecasting in PT. XYZ by using the Method of Holt Winter Multiplicative
Shaleh, W.; Rasim; Wahyudin
2018-01-01
Problems at PT. XYZ currently only rely on manual bookkeeping, then the cost of production will swell and all investments invested to be less to predict sales and inventory of goods. If the inventory prediction of goods is to large, then the cost of production will swell and all investments invested to be less efficient. Vice versa, if the inventory prediction is too small it will impact on consumers, so that consumers are forced to wait for the desired product. Therefore, in this era of globalization, the development of computer technology has become a very important part in every business plan. Almost of all companies, both large and small, use computer technology. By utilizing computer technology, people can make time in solving complex business problems. Computer technology for companies has become an indispensable activity to provide enhancements to the business services they manage but systems and technologies are not limited to the distribution model and data processing but the existing system must be able to analyze the possibilities of future company capabilities. Therefore, the company must be able to forecast conditions and circumstances, either from inventory of goods, force, or profits to be obtained. To forecast it, the data of total sales from December 2014 to December 2016 will be calculated by using the method of Holt Winters, which is the method of time series prediction (Multiplicative Seasonal Method) it is seasonal data that has increased and decreased, also has 4 equations i.e. Single Smoothing, Trending Smoothing, Seasonal Smoothing and Forecasting. From the results of research conducted, error value in the form of MAPE is below 1%, so it can be concluded that forecasting with the method of Holt Winter Multiplicative.
Directory of Open Access Journals (Sweden)
Yuli Dwi Astanti
2015-04-01
Full Text Available PT. XYZ is a pharmaceutical company that manufactures both pharmaceuticals and herbal medicinal chemistry. The drug is a vital necessity to society, therefore, the drug production process must be maintained so that its performance can be met drug availability. One way to maintain smooth production process is to maintain engine performance. An engine production facility that is vital and requires periodic maintenance or at any time in case of damage. Each performed maintenance or repairs due to damage, an engine needs replacement parts for the machine to run as before. To support the maintenance activities, PT. XYZ has a warehouse used to store spare parts. During this time, parts storage system in PT. XYZ is not based on consideration of the appropriate classification of its characteristics, but each part has different characteristics, both in terms of price, suppliers, materials, usage, and so on. Due to the large number of stocks and the importance of spare parts, the supply system must be considered in order not to cause any harm to the company. The present study will attempt to analyze the system parts inventory in the warehouse by using MUSIC-3D View of Spares. MUSIC-3D View of spares in the analysis using a 3-dimensional approach that values consumption, availability and critically. The third dimension is represented by the three approaches, namely System ABC, VED, and SDE. Based on the results of the analysis of MUSIC-3D Views of Spares in mind that parts each having a different classification, so it requires a different treatment according to their classification. Keywords : spare parts, supplies, MUSIC-3D View of Spares
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O. V. Zhukov
2017-01-01
Full Text Available Inventory management for a trading company is a vital task, which requires processing significant amounts of information. Through the application of ABC/XYZ-analysis of the nomenclature within the enterprise ERP-system, it is possible to increase significantly the efficiency of inventory management, in accordance with Pareto principle concentrating on managing the most important categories of goods. Various researchers dealt with the methods of ABC/XYZ-analysis itself but its usage as a part of the inventory management and procurement subsystem has a number of essential features, ignoring of which can lead to tangible negative consequences. The article discusses the methods and key problems of application of ABC/XYZ-analysis within the enterprise management accounting information system. For each of the factors that can affect the reliability of sales and procurement statistics and distort the results of the classification of goods, we have formulated the proposals to minimize the negative impact of that specific factor. Proposed methods allow reducing the impact of the following factors: availability of conditions for duplicate nomenclature to appear within the enterprise accounting software, the lack of a unified approach to the formation of names for newly created items of nomenclature, frequent changes in the products range of the suppliers, excessive detailing of information about a product in its name. The results of successfully implemented analysis and classification of goods can be used for a wide range of tasks varying from implementing effective inventory control to general planning and forecasting commodity flows as a part of the enterprise budgeting model. Solving these problems will harmoniously fit the inventory management in the managerial accounting system making it an effective tool in achieving strategic business goals.
Sembiring, N.; Panjaitan, N.; Saragih, A. F.
2018-02-01
PT. XYZ is a manufacturing company that produces fresh fruit bunches (FFB) to Crude Palm Oil (CPO) and Palm Kernel Oil (PKO). PT. XYZ consists of six work stations: receipt station, sterilizing station, thressing station, pressing station, clarification station, and kernelery station. So far, the company is still implementing corrective maintenance maintenance system for production machines where the machine repair is done after damage occurs. Problems at PT. XYZ is the absence of scheduling engine maintenance in a planned manner resulting in the engine often damaged which can disrupt the smooth production. Another factor that is the problem in this research is the kernel station environment that becomes less convenient for operators such as there are machines and equipment not used in the production area, slippery, muddy, scattered fibers, incomplete use of PPE, and lack of employee discipline. The most commonly damaged machine is in the seed processing station (kernel station) which is cake breaker conveyor machine. The solution of this problem is to propose a schedule plan for maintenance of the machine by using the method of reliability centered maintenance and also the application of 5S. The result of the application of Reliability Centered maintenance method is obtained four components that must be treated scheduled (time directed), namely: for bearing component is 37 days, gearbox component is 97 days, CBC pen component is 35 days and conveyor pedal component is 32 days While after identification the application of 5S obtained the proposed corporate environmental improvement measures in accordance with the principles of 5S where unused goods will be moved from the production area, grouping goods based on their use, determining the procedure of cleaning the production area, conducting inspection in the use of PPE, and making 5S slogans.
Anisotropy modulated stepwise magnetization in triangular Heisenberg antiferromagnet
International Nuclear Information System (INIS)
Yao Xiaoyan; Liu Junming; Lo, Veng Cheong
2011-01-01
During the course of tuning anisotropy from Ising type to zero, the variation of magnetization (M) steps against magnetic field (h) is investigated in a triangular antiferromagnetic Heisenberg model using Monte Carlo techniques. It is revealed that the anisotropy is an essential key to induce the temperature-dependent stepwise M(h) curve observed in frustrated magnetic system, and it can be employed to modulate this steplike magnetic behavior effectively. When the anisotropy is strengthened, a ground state transition occurs from the homogeneous 120 o triangular structure to the collinear partially disordered antiferromagnetic state. No M step is detected in the system without anisotropy. But if the anisotropy is nonzero, the M 0 /3 step (where M 0 is the saturated M) will emerge on M(h) curve, which is due to an h-induced quasi-collinear ferrimagnetic state. This M 0 /3 step can be extended by increasing the anisotropy. When the M 0 /3 plateau dominates the h-range broad enough, the equidistant metastable substeps, which originates from the disorders frozen in the frustrated collinear spin structure, appear to be superposed on the M 0 /3 plateau. Thus the system with a strong anisotropy presents the whole temperature evolution of stepwise M(h) curve in quantitative agreement with the experiments of Ca 3 Co 2 O 6 . - Highlights: → Variation of M steps is investigated by tuning anisotropy from Ising type to zero. → Anisotropy is essential to induce T-dependent multistep M against magnetic field. → Simulation with strong anisotropy reproduces T-evolution of M steps in Ca 3 Co 2 O 6 . → Metastable substeps at low T can be enhanced by increasing anisotropy.
Abstract: One-dimensional Heisenberg antiferromagnets with random exchange (invited)
Clark, W. G.
1982-03-01
In recent years a class of materials has emerged whose low-temperature magnetic properties are those of a random exchange Heisenberg antiferromagnetic chain (REHAC).1 Most of them are based on conducting salts of TCNQ with disorder, which can be intrinsic or induced. The most studied example is quinolinium ditetracyanoquinodimethanide [Qn(TCNQ)2], which at high T has one unpaired spin per formula unit. Several characteristic properties exhibited by this material are discussed. They include the susceptibility χ∝T-α, low-temperature magnetization M∝H1-α, low field H and temperature T specific heat C∝T1-α, exchange narrowed ESR lines,2 two component electron spin relaxation to the exchange reservoir and the bath,2 and the absence of any three-dimensional ordering transition down to T˜1 mK.3 The exponent α shows a quasiuniversal behavior,4 with α≃0.8. Recent models for the thermodynamics of H using renormalization methods are discussed and compared with the experimental results.1 This report is based in part on work supported by NSF Grant DMR 81-03085. 1For a recent review of this subject, see W. G. Clark, Physics in One Dimension, edited by J. Bernasconi and T. Schneider (Springer, Berlin, 1981), p. 289. 2L. C. Tippie and W. G. Clark, Phys. Rev. B 23, 5854 (1981). 3H. M. Bozler, C. M. Gould, and W. G. Clark, Phys. Rev. Lett. 45, 1303 (1980). 4J. Sanny, G. Grüner, and W. G. Clark, Solid State Commun. 35, 657 (1980).
Jonny, Jonny
2016-01-01
The goal of the research was to evaluate the effectiveness of Kirkpatrick model and Return on Investment of Training at PT XYZ. Observation was applied to this research. The result has shown several facts such as trainee’s feedback score was 4,62 above 4,10 as required by the company in terms of reaction, the average final exam score was 3,66 above 3,00 as required by the company in terms of learning, the trainees’ superiors’ feedback score was 3,53 above 3,00 as required by the company and R...
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Krishna Rahadian
2014-10-01
Full Text Available The purpose of this study was to evaluate the effects of the process of ISO 27001 with respect to the confidentiality of customer cellular card Jakarta and to improve cellular card customer data confidentiality at PT.XYZ from data leakage of the customer data due to the third party involvement, clean-desk policy, and access right. Recommendation regarding the improvement is provided after reviewing the confidentiality of customer data. The survey in this study is conducted by questionnaire. From the evaluation results of the questionnaire, it is concluded that the larger customer data leaks are mainly caused by the external factors.
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I Nyoman Sutapa
2001-01-01
Full Text Available This paper discusses a jobs scheduling on a single machine to minimize variance of job completion time. The objective is especially important in situations where it is desirable to provide customers or jobs with approximately the same treatment. In this case, data are collected from P.T. 'XYZ'. The focus of discussion is LB/KB Departement (Leather Board/Carton Board with carton board's production line, which produces carton board. Carton board's size is 150 x 110 cm and its thickness from 0,6 mm to 2,5 mm. In this paper a comparison analysis, the deviation of the objective value given by a heuristic (Vh method from the objective value given by P.T. 'XYZ' (Vp, is made. The percentage of deviation Vh from Vp is 50,36 %, which shows that the performance of heuristic is better, that is variance of job completion time by heuristic method smaller than by P.T. 'XYZ'. Besides the above discussion, the weakness dan superiority of heuristic are analyzed too. Abstract in Bahasa Indonesia : Makalah ini membahas penjadwalan jobs pada single machine dengan tujuan meminimumkan varians waktu penyelesaian job, yaitu untuk memberikan konsumen atau jobs kurang lebih perlakuan yang sama. Data yang diambil dalam pembahasan ini berasal dari perusahaan P.T. 'XYZ', di mana departemen yang menjadi fokus pembahasan adalah Departemen LB/KB (Leather Board/Karton Board dengan lintasan produksi karton board yang menghasilkan produk carton board ukuran 150 x 110 cm, dengan ketebalan 0,6 mm sampai dengan 2,5 mm. Dalam makalah ini dilakukan analisis perbandingan jadwal jobs pada proses produksi di perusahaan yang telah ada dengan jadwal jobs menggunakan metode heuristic, yaitu menggunakan persentase penyimpangan Vh (varians waktu penyelesaian jobs metode heuristic dari Vp (varians waktu penyelesaian jobs perusahaan. Dari hasil analisis didapatkan bahwa persentase penyimpangan Vh dari Vp sebesar 50,36%, hal ini menunjukkan bahwa performance metode heuristic lebih baik, yaitu
Thermodynamics and phase transitions of the pinwheel-distorted Kagome lattice Heisenberg model
Khatami, Ehsan; Singh, Rajiv R. P.; Rigol, Marcos
2012-02-01
We study the Heisenberg model on the pinwheel-distorted Kagome lattice as observed in the material Rb2Cu3SnF12. Experimentally relevant thermodynamic properties at finite temperatures are computed utilizing numerical linked-cluster expansions [1]. We introduce a Lanczos-based zero-temperature numerical linked-cluster expansion and study the approach of the pinwheel distorted lattice to the uniform Kagome lattice Heisenberg model. We find strong evidence for a phase transition before the uniform limit is reached, implying that the ground state of the Kagome lattice Heisenberg model is likely not pinwheel dimerized and is stable to finite pinwheel dimerizing perturbations [2]. [4pt] [1] M. Rigol and R. R. P. Singh, Phys. Rev. Lett. 98, 207204 (2007); Phys. Rev. B 76, 184403 (2007). [0pt] [2] E. Khatami, R. R. P. Singh, M. Rigol, preprint: arXiv:1105.4147
Directory of Open Access Journals (Sweden)
Ignatius Jeffrey
2011-11-01
Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} This study was designed to extend the Hersey and Blanchard's Situational Leadership Model to test the match of adaptability leadership style to the maturity level of subordinates using the LEAD-Self instrument and Readiness Scale of the Center for Leadership Studies. Maturity level of subordinate was analyzed based on the maturity level of employment (ability and psychological maturity (willingness to given work to subordinates. Also, to test compatibility with the leadership style with desired subordinates leadership style using LEAD-Other instrument. Leadership style is a combination of task behavior and behavioral relationships that will produce a directing coaching, participating delegating style. In addition, this study also tested the suitability of the existing organizational culture with the expectation organization culture. Effective matching leadership style and organizational culture is measured by the achievement of individual performance. The purpose of this study is to analyze the influence of matching between leadership style with the follower’s readiness level (X1, the leader's perceived leadership style with leader’s desired leadership style (X2, and the existing organizational culture with the expectation’s employees (X3 on the individual performance (Y1. The object of research was conducted at PT. XYZ and method of data retrieval is done by the census, while the method of analysis of this study was using the Structural Equation Modeling (SEM. Keywords
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Renty Anugerah Mahaji Puteri
2016-01-01
Full Text Available Agar proses produksi bisa berjalan dengan lancar, diperlukan improvement. Dalam pembahasan ini, improvement yang akan dilakukan terkait dengan proses pembentukan part bracket support air tank. Adapun metode yang digunakan pada penelitian ini adalah PDCA (Plan Do Check Action. Metode ini diangkat penulis sebagai metode yang paling cocok untuk diterapkan pada perusahaan yang bergerak di bidang otomotif seperti PT. XYZ ini. Yang menjadi titik fokus dari improvement yang akan dilakukan saat ini adalah dies untuk part bracket support air tank. Produk ini dianggap cocok untuk menjadi bahan improvement karena merupakan new project. Sehingga dapat melakukan improvement yang ekstrim sekalipun tanpa harus mengganggu produksi yang sedang berlangsung. Untuk itu penyesuaian atau rekayasa terhadap dies dari part tersebut akan dilaksanakan guna mencapai hasil atau target yang diinginkan.Adapun hasil yang diharapkan dari penelitian ini adalah tercukupinya kapasitas mesin untuk melakukan proses – proses yang harus dilakukan untuk pembuatan part bracket support air tank. Selain itu, kualitas dari produk yang dibuat juga menjadi item yang harus tetap dijaga. Karena kualitas dari produk yang dibuat akan menjaga kepercayaan customer terhadap PT. XYZ.
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TRI ALIT TRESNA PUTRA
2017-05-01
Full Text Available The aim of this study was to demonstrate the application of Statistics Quality Control in fierce industries. By observing Batik production process at PT XYZ as a case in this work, we applied Six Sigma Method to analyze defective product and their cause while also measure overall quality goodness. Six Sigma is a method to improve a process and reduce defects in productions into 3.4 defects per million productions. We use handprint batik productions at PT XYZ as a case in this study. The method is involving Define, Measure and Analyze (DMA phases. By using Six Sigma, it was obtained that the quality of handprint batik are quite good with sigma of 3.105 and defect rate of 54.269 million production (DPMO. There are four defect causes of handprint batik namely: ripped fabric, shallowness, perforation, and mispattern which contribute 41,7%, 35,8%, 15%, 7,5% respectively from overall defects. The main cause of defects is the carelessness of workers in production process. Therefore we need to reduce the carelessness to improve production quality.
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Ari Setyorini
2011-04-01
Full Text Available The purpose of this study is to answer whether the intervention with reeducative approach and power strategy can improve punctuality behavior among students in the class XYZ. Methodology is carried out by using the method of intervention with reeducative approach and power strategy involving 55 students at the XYZ class who is in their third semester at a private university. Intervention is conducted by providing re-learning on the importance of timely discipline behaviors by using an agent of change in the course lecturers is considered as having power over these students. The average number of students prior to the intervention of delay is 16 people (29.9% to 4 (7:27% after intervention resulting in a decrease of 21.82%. Things that cause the success of this project is the advantages of interventions, among others, changing the mindset of the target behavior regarding lateness in class, with presence of education during socialization, enabling awareness of the importance of internal discipline.
Partition functions of classical Heisenberg spin chains with arbitrary and different exchange
International Nuclear Information System (INIS)
Cregg, P J; GarcIa-Palacios, J L; Svedlindh, P
2008-01-01
The classical Heisenberg model has been effective in modelling exchange interactions in molecular magnets. In this model, the partition function is important as it allows the calculation of the magnetization and susceptibility. For an ensemble of N-spin sites, this typically involves integrals in 2N dimensions. Here, for two-, three- and four-spin nearest neighbour open linear Heisenberg chains these integrals are reduced to sums of known functions, using a result due to Gegenbauer. For the case of the three- and four-spin chains, the sums are equivalent in form to the results of Joyce. The general result for an N-spin chain is also obtained
Spinon decay in the spin-1/2 Heisenberg chain with weak next nearest neighbour exchange
International Nuclear Information System (INIS)
Groha, Stefan; Essler, Fabian H L
2017-01-01
Integrable models support elementary excitations with infinite lifetimes. In the spin-1/2 Heisenberg chain these are known as spinons. We consider the stability of spinons when a weak integrability breaking perturbation is added to the Heisenberg chain in a magnetic field. We focus on the case where the perturbation is a next nearest neighbour exchange interaction. We calculate the spinon decay rate in leading order in perturbation theory using methods of integrability and identify the dominant decay channels. The decay rate is found to be small, which indicates that spinons remain well-defined excitations even though integrability is broken. (paper)
Z2-vortex lattice in the ground state of the triangular Kitaev-Heisenberg model
Daghofer, Maria; Rousochatzakis, Ioannis; Roessler, Ulrich K.; van den Brink, Jeroen
2013-03-01
Investigating the classical Kitaev-Heisenberg Hamiltonian on a triangular lattice, we establish the presence of an incommensurate non-coplanar magnetic phase, which is identified as a lattice of Z2 vortices. The vortices, topological point defects in the SO(3) order parameter of the nearby Heisenberg antiferromagnet, are not thermally excited but due to the spin-orbit coupling and arise at temperature T --> 0 . This Z2-vortex lattice is stable in a parameter regime relevant to iridates. We show that in the other, strongly anisotropic, limit a robust nematic phase emerges. Sponsored by the DFG (Emmy-Noether program).
Chiral-glass transition in a diluted dipolar-interaction Heisenberg system
International Nuclear Information System (INIS)
Zhang Kaicheng; Liu Guibin; Zhu Yan
2011-01-01
Recently, numerical simulations reveal that a spin-glass transition can occur in the three-dimensional diluted dipolar system. By defining the chirality of triple spins in a diluted dipolar Heisenberg spin glass, we study the chiral ordering in the system using parallel tempering algorithm and heat bath method. The finite-size scaling analysis reveals that the system undergoes a chiral-glass transition at finite temperature. - Highlights: → We define the chirality in a diluted dipolar Heisenberg system. → The system undergoes a chiral-glass transition at finite temperature. → We extract the critical exponents of the chiral-glass transition.
Emergent Power-Law Phase in the 2D Heisenberg Windmill Antiferromagnet: A Computational Experiment
Jeevanesan, Bhilahari; Chandra, Premala; Coleman, Piers; Orth, Peter P.
2015-10-01
In an extensive computational experiment, we test Polyakov's conjecture that under certain circumstances an isotropic Heisenberg model can develop algebraic spin correlations. We demonstrate the emergence of a multispin U(1) order parameter in a Heisenberg antiferromagnet on interpenetrating honeycomb and triangular lattices. The correlations of this relative phase angle are observed to decay algebraically at intermediate temperatures in an extended critical phase. Using finite-size scaling we show that both phase transitions are of the Berezinskii-Kosterlitz-Thouless type, and at lower temperatures we find long-range Z6 order.
Critical behavior of the quantum spin- {1}/{2} anisotropic Heisenberg model
Sousa, J. Ricardo de
A two-step renormalization group approach - a decimation followed by an effective field renormalization group (EFRG) - is proposed in this work to study the critical behavior of the quantum spin- {1}/{2} anisotropic Heisenberg model. The new method is illustrated by employing approximations in which clusters with one, two and three spins are used. The values of the critical parameter and critical exponent, in two- and three-dimensional lattices, for the Ising and isotropic Heisenberg limits are calculated and compared with other renormalization group approaches and exact (or series) results.
Exact Baker–Campbell–Hausdorff formula for the contact Heisenberg algebra
International Nuclear Information System (INIS)
Bravetti, Alessandro; Garcia-Chung, Angel; Tapias, Diego
2017-01-01
In this work we introduce the contact Heisenberg algebra which is the restriction of the Jacobi algebra on contact manifolds to the linear and constant functions. We give the exact expression of its corresponding Baker–Campbell–Hausdorff formula. We argue that this result is relevant to the quantization of contact systems. (paper)
Criticality of the anisotropic quantum Heisenberg model on a simple cubic lattice
International Nuclear Information System (INIS)
Mariz, A.M.; Tsallis, C.; Santos, R.M.Z. dos; Santos, Raimundo R. dos.
1984-11-01
Within a Real Space Renormalization Group Framework, the criticality (phase diagram, and critical thermal and crossover exponents) of the spin 1/2 - anisotropic quantum Heisenberg ferromagnet on a simple cubic lattice is studied. The results obtained are in antisfactory agreement with known results whenever available. (Author) [pt
Spin wave analysis to the spatially-anisotropic Heisenberg antiferromagnet on triangular lattice
Trumper, Adolfo E.
1998-01-01
We study the phase diagram at T=0 of the antiferromagnetic Heisenberg model on the triangular lattice with spatially-anisotropic interactions. For values of the anisotropy very close to J_alpha/J_beta=0.50, conventional spin wave theory predicts that quantum fluctuations melt the classical structures, for S=1/2. For the regime J_beta
Weyl-Heisenberg frames, translation invariant systems, and the Walnut representation
DEFF Research Database (Denmark)
Casazza, P.G.; Christensen, Ole; Janssen, A. J. E. M.
2001-01-01
We present a comprehensive analysis of the convergence properties of the frame operators of Weyl-Heisenberg systems and shift-invariant systems, and relate these to the convergence of the Walnut representation. We give a deep analysis of necessary conditions and sufficient conditions for converge...
On the Quantum Inverse problem for the continuous Heisenberg spin chain with axial anisotropy
International Nuclear Information System (INIS)
Roy Chowdhury, A.; Chanda, P.K.
1986-06-01
We have considered the Quantum Inverse problem for the continuous form of Heisenberg spin chain with anisotropy. The form of quantum R-matrix, the commutation rules for the scattering data, and the explicit structure of the excitation spectrum are obtained. (author)
The existence of horizontal envelopes in the 3D-Heisenberg group
Huang, Yen-Chang
2018-01-01
By using the support function on the $xy$-plane, we show the necessary and sufficient conditions for the existence of envelopes of horizontal lines in the 3D-Heisenberg group. A method to construct horizontal envelopes from the given ones is also derived, and we classify the solutions satisfying the construction.
Higher-spin cluster algorithms: the Heisenberg spin and U(1) quantum link models
Energy Technology Data Exchange (ETDEWEB)
Chudnovsky, V
2000-03-01
I discuss here how the highly-efficient spin-1/2 cluster algorithm for the Heisenberg antiferromagnet may be extended to higher-dimensional representations; some numerical results are provided. The same extensions can be used for the U(1) flux cluster algorithm, but have not yielded signals of the desired Coulomb phase of the system.
Higher-spin cluster algorithms: the Heisenberg spin and U(1) quantum link models
International Nuclear Information System (INIS)
Chudnovsky, V.
2000-01-01
I discuss here how the highly-efficient spin-1/2 cluster algorithm for the Heisenberg antiferromagnet may be extended to higher-dimensional representations; some numerical results are provided. The same extensions can be used for the U(1) flux cluster algorithm, but have not yielded signals of the desired Coulomb phase of the system
Wouters, B.; De Nardis, J.; Brockmann, M.; Fioretto, D.; Rigol, M.; Caux, J.-S.
2014-01-01
We study quenches in integrable spin-1/2 chains in which we evolve the ground state of the antiferromagnetic Ising model with the anisotropic Heisenberg Hamiltonian. For this nontrivially interacting situation, an application of the first-principles-based quench-action method allows us to give an
Odd number of coupled antiferromagnetic anisotropic Heisenberg chains: Spin wave theory
International Nuclear Information System (INIS)
Benyoussef, A.
1996-10-01
The effect of the chain and perpendicular anisotropies on the energy gap for odd number of coupled quantum spin-1/2 antiferromagnetic anisotropic Heisenberg chains is investigated using a spin wave theory. The energy gap opens above a critical anisotropic value. The known results of the isotropic case have been obtained. (author). 11 refs, 4 figs
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Abdallah El Hamidi
2004-01-01
Full Text Available We establish nonexistence results to systems of differential inequalities on the (2N+1-Heisenberg group. The systems considered here are of the type (ESm. These nonexistence results hold for N less than critical exponents which depend on pi and γi, 1≤i≤m. Our results improve the known estimates of the critical exponent.
Zimmerman, Scott
This thesis focuses on analysis in and the geometry of the Heisenberg group as well as geometric properties of Sobolev mappings. It begins with a detailed introduction to the Heisenberg group. After, we see a new and elementary proof for the structure of geodesics in the sub-Riemannian Heisenberg group. We also prove that the Carnot-Caratheodory metric is real analytic away from the center of the group. Next, we prove a version of the classical Whitney Extension Theorem for curves in the Heisenberg group. Given a real valued function defined on a compact set in Euclidean space, the classical Whitney Extension Theorem from 1934 gives necessary and sufficient conditions for the existence of a Ck extension defined on the entire space. We prove a version of the Whitney Extension Theorem for C1 , horizontal curves in the Heisenberg group. We then turn our attention to Sobolev mappings. In particular, given a Lipschitz map from a compact subset Z of Euclidean space into a Lipschitz connected metric space, we construct a Sobolev extension defined on any bounded domain containing Z. Finally, we generalize a classical result of Dubovitskiǐ for smooth maps to the case of Sobolev mappings. In 1957, Dubovitskiǐ generalized Sard's classical theorem by establishing a bound on the Hausdorff dimension of the intersection of the critical set of a smooth map and almost every one of its level sets. We show that Dubovitskiǐ's theorem can be generalized to Wk,p loc (R n,Rm) mappings for all positive integers k and p > n.
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Jonny Jonny
2016-09-01
Full Text Available The goal of the research was to evaluate the effectiveness of Kirkpatrick model and Return on Investment of Training at PT XYZ. Observation was applied to this research. The result has shown several facts such as trainee’s feedback score was 4,62 above 4,10 as required by the company in terms of reaction, the average final exam score was 3,66 above 3,00 as required by the company in terms of learning, the trainees’ superiors’ feedback score was 3,53 above 3,00 as required by the company and Return on Investment of Training (ROI-Training was 58,88% above 15% as required by the company. With these results, the company can conclude that the program is effective in nurturing its supervisory leaders.
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Jonny Jonny
2012-06-01
Full Text Available PT XYZ received an offer of toll manufacturing services from its client as much as 360 units at a price of Rp14.000 for four years. To be able to fulfill the offer, the company must issue an investment of Rp1,3 billion for the plant expansion regarding to the limited capacity and specificity of the engine that must be purchased separately. There is also some additional operational cost for the company. Based on the analysis of costvolume-profit (CVP the company realized that the price offered is far below the desired corporate profit by 27% so that the new price agreed upon in the negotiation is Rp16.000. Meanwhile, using the price agreement and macroeconomic assumption for the next four years, the company can finally concluded to accept the offer of its client with a value weighted NPV up to Rp306, 5 million based on the incremental analysis.
Directory of Open Access Journals (Sweden)
Aman Mustika
2017-09-01
Full Text Available Biodiesel is considered as one of the alternative eco-friendly fuels. Besides, the government also issued policy related to biodiesel that is CPO Supporting Fund (CSF Policy. The aim of the research is to identify Business model canvas (BMC biodiesel industry in PT XYZ and to know the strategies to develop business from biodiesel industry in line with the CPO supporting fund policy. The analysis tool used in this research is BMC, SWOT and Quantitative Strategic Planning Matrix (QSPM. The research results in identifying BMC of PT XYZ is customer segment that the company serves in the form of domestic as well international customers. The value the company offers is biodiesel quality that is in accordance with SNI standard and the distribution is at the company’s cost; the relationship built with the customers is by communities and co-creation; the marketing network through stock exchanges and commodity exchanges; the revenue obtained from selling biodiesel and the price difference between biodiesel and solar from BPDPKS; the company’s resources are human resource, raw material resource, and financial resource; the main activities carried out by the company is CPO process to become biodiesel and sale; the company’s partners are GAPKI, BPDPKS and APROBI; the cost structure is operational cost, workers’ salary, and CPO levy fund. Furthermore, the strategy to develop biodiesel industry in line with the rapid increase of competitiveness is to increase the biodiesel production capacity and communication improvement and CRM to improve customers’ service.Keywords: biodiesel, CPO supporting fund (CSF, levy fund, vegetable oil (BBN, business model canvas (BMC
Sandvik, A. W.
1998-01-01
We present results of extensive quantum Monte Carlo simulations of the three-dimensional (3D) S=1/2 Heisenberg antiferromagnet. Finite-size scaling of the spin stiffness and the sublattice magnetization gives the critical temperature Tc/J = 0.946 +/- 0.001. The critical behavior is consistent with the classical 3D Heisenberg universality class, as expected. We discuss the general nature of the transition from quantum mechanical to classical (thermal) order parameter fluctuations at a continuo...
Directory of Open Access Journals (Sweden)
Syed Masood
2016-12-01
Full Text Available In this paper, we will propose the most general form of the deformation of Heisenberg algebra motivated by the generalized uncertainty principle. This deformation of the Heisenberg algebra will deform all quantum mechanical systems. The form of the generalized uncertainty principle used to motivate these results will be motivated by the space fractional quantum mechanics, and non-locality in quantum mechanical systems. We also analyse a specific limit of this generalized deformation for one dimensional system, and in that limit, a nonlocal deformation of the momentum operator generates a local deformation of all one dimensional quantum mechanical systems. We analyse the low energy effects of this deformation on a harmonic oscillator, Landau levels, Lamb shift, and potential barrier. We also demonstrate that this deformation leads to a discretization of space.
Heisenberg 1901-1976 : le témoignage de sa femme
Heisenberg, Elisabeth
1990-01-01
Une femme raconte la vie de son mari, Werner Heisenberg, Prix Nobel de Physique 1932. Après une enfance heureuse, ce brillant étudiant fut l'élève d'Albert Einstein, Niels Bohr, Arnold Sommerfeld. Mais à l'époque de la montée du nazisme, le grand physicien refusa de quitter son pays, cautionnant ainsi le régime d'Hitler et participant à "l'effort de guerre", c'est-à-dire à la course à la bombe. Le témoignage d'Elisabeth Heisenberg bien que naturellement subjectif, permet de saisir les ressorts psychologiques du comportement d'un savant face aux terrifiantes réalités de son époque.
An addendum to the Heisenberg-Euler effective action beyond one loop
International Nuclear Information System (INIS)
Gies, Holger; Karbstein, Felix
2017-01-01
We study the effective interactions of external electromagnetic fields induced by fluctuations of virtual particles in the vacuum of quantum electrodynamics. Our main focus is on these interactions at two-loop order. We discuss in detail the emergence of the renowned Heisenberg-Euler effective action from the underlying microscopic theory of quantum electrodynamics, emphasizing its distinction from a standard one-particle irreducible effective action. In our explicit calculations we limit ourselves to constant and slowly varying external fields, allowing us to adopt a locally constant field approximation. One of our main findings is that at two-loop order there is a finite one-particle reducible contribution to the Heisenberg-Euler effective action in constant fields, which was previously assumed to vanish. In addition to their conceptual significance, our results are relevant for high-precision probes of quantum vacuum nonlinearity in strong electromagnetic fields.
Karbstein, Felix
2017-04-01
We use a locally constant field approximation (LCFA) to study the one-loop Heisenberg-Euler effective action in a particular class of slowly varying inhomogeneous electric fields of Lorentzian shape with 0 ≤d effective action can be represented in terms of a single parameter integral, with the constant field effective Lagrangian with rescaled argument as integration kernel. The imaginary part of the Heisenberg-Euler effective action contains information about the instability of the quantum vacuum towards the formation of a state with real electrons and positrons. Here, in particular, we focus on the dependence of the instantaneous vacuum decay rate on the dimension d of the field inhomogeneity. Specifically, for weak fields, we find an overall parametric suppression of the effect with (E0/Ecr)d/2, where E0 is the peak field strength of the inhomogeneity and Ecr the critical electric field strength.
An addendum to the Heisenberg-Euler effective action beyond one loop
Energy Technology Data Exchange (ETDEWEB)
Gies, Holger; Karbstein, Felix [Helmholtz-Institut Jena,Fröbelstieg 3, 07743 Jena (Germany); Theoretisch-Physikalisches Institut, Abbe Center of Photonics,Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany)
2017-03-21
We study the effective interactions of external electromagnetic fields induced by fluctuations of virtual particles in the vacuum of quantum electrodynamics. Our main focus is on these interactions at two-loop order. We discuss in detail the emergence of the renowned Heisenberg-Euler effective action from the underlying microscopic theory of quantum electrodynamics, emphasizing its distinction from a standard one-particle irreducible effective action. In our explicit calculations we limit ourselves to constant and slowly varying external fields, allowing us to adopt a locally constant field approximation. One of our main findings is that at two-loop order there is a finite one-particle reducible contribution to the Heisenberg-Euler effective action in constant fields, which was previously assumed to vanish. In addition to their conceptual significance, our results are relevant for high-precision probes of quantum vacuum nonlinearity in strong electromagnetic fields.
Three types magnetic moment distribution of nonlinear excitations in a Heisenberg helimagnet
Energy Technology Data Exchange (ETDEWEB)
Qi, Jian-Wen [School of Physics, Northwest University, Xi' an 710069 (China); Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi' an 710069 (China); Li, Zai-Dong [Department of Applied Physics, Hebei University of Technology, Tianjin 300401 (China); Yang, Zhan-Ying, E-mail: zyyang@nwu.edu.cn [School of Physics, Northwest University, Xi' an 710069 (China); Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi' an 710069 (China); Yang, Wen-Li [Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi' an 710069 (China); Institute of Modern Physics, Northwest University, Xi' an 710069 (China)
2017-06-15
Highlights: • Three different types of soliton excitations under the spin-wave background are demonstrated in spin chain system. • The magnetic moment distributions corresponding to these solitons are characterized in detail. • The formation mechanisms of those excitations are explained by the magnon density distribution. - Abstract: We study the nonlinear spin dynamics of an anisotropic Heisenberg helimagnet in a fourth-order integrable nonlinear Schrödinger equation. We demonstrate that there are three types of nonlinear spin excitations on a spin-wave background in the Heisenberg helimagnet, notably including anti-dark soliton, W-shaped soliton, and multi-peak soliton. The magnetic moment distribution that corresponds to each of these are characterized in detail. Additionally, the formation mechanism is clarified by the magnon density distribution.
A representation of Weyl-Heisenberg Lie algebra in the quaternionic setting
Muraleetharan, B.; Thirulogasanthar, K.; Sabadini, I.
2017-10-01
Using a left multiplication defined on a right quaternionic Hilbert space, linear self-adjoint momentum operators on a right quaternionic Hilbert space are defined in complete analogy with their complex counterpart. With the aid of the so-obtained position and momentum operators, we study the Heisenberg uncertainty principle on the whole set of quaternions and on a quaternionic slice, namely on a copy of the complex plane inside the quaternions. For the quaternionic harmonic oscillator, the uncertainty relation is shown to saturate on a neighborhood of the origin in the case we consider the whole set of quaternions, while it is saturated on the whole slice in the case we take the slice-wise approach. In analogy with the complex Weyl-Heisenberg Lie algebra, Lie algebraic structures are developed for the quaternionic case. Finally, we introduce a quaternionic displacement operator which is square integrable, irreducible and unitary, and we study its properties.
Modified Migdal-Kadanoff renormalization for the spin-(1/2 anisotropic Heisenberg model
Lee, Felix; Chen, H. H.; Tseng, H. C.
1988-07-01
The spin-(1/2 anisotropic Heisenberg model is studied by a modified Migdal-Kadanoff method, called the cluster-decimation approximation. The free energy for a small cluster of spins with an appropriate boundary condition is assumed to be preserved in the bond-moving step and the approximate decimation of Suzuki and Takano is adopted in the site-decimation step. Critical temperatures obtained by the present method are in general much better than those determined by preserving the high-temperature series expansion of the free energy. In particular the XY fixed point and the isotropic Heisenberg fixed point for the square lattice are not found in the present calculation.
Un'estrema solitudine la vita e l'opera di Werner Heisenberg
Cassidy, David C
1996-01-01
Il genio di Werner Heisenberg attraversa l'orizzonte della fisica del nostro secolo come una meteora. Testimoniano della fecondità e dell'originalità del suo pensiero non solo il Nobel che gli fu assegnato a soli 32 anni, ma soprattutto i decisivi impulsi da lui dati alla fisica quantistica, alla teoria delle particelle elementari, alla teoria del nucleo. Si deve a Heisenberg quel "principio di indeterminazione" che ha rivoluzionato non solo il corso della fisica ma il modo di concepire la posizione dell'uomo nell'universo. L'interesse del libro, però, vuole andare oltre la fisica, giacché il curriculum del "ragazzo di campagna dei biondi capelli" rispecchia in forma emblematica l'ambiguo rapporto della scienza col potere.
Achieving the Heisenberg limit in quantum metrology using quantum error correction.
Zhou, Sisi; Zhang, Mengzhen; Preskill, John; Jiang, Liang
2018-01-08
Quantum metrology has many important applications in science and technology, ranging from frequency spectroscopy to gravitational wave detection. Quantum mechanics imposes a fundamental limit on measurement precision, called the Heisenberg limit, which can be achieved for noiseless quantum systems, but is not achievable in general for systems subject to noise. Here we study how measurement precision can be enhanced through quantum error correction, a general method for protecting a quantum system from the damaging effects of noise. We find a necessary and sufficient condition for achieving the Heisenberg limit using quantum probes subject to Markovian noise, assuming that noiseless ancilla systems are available, and that fast, accurate quantum processing can be performed. When the sufficient condition is satisfied, a quantum error-correcting code can be constructed that suppresses the noise without obscuring the signal; the optimal code, achieving the best possible precision, can be found by solving a semidefinite program.
Energy Technology Data Exchange (ETDEWEB)
Masood, Syed [Department of Physics, International Islamic University, H-10 Sector, Islamabad (Pakistan); Faizal, Mir, E-mail: mirfaizalmir@gmail.com [Irving K. Barber School of Arts and Sciences, University of British Columbia – Okanagan, Kelowna, BC V1V 1V7 (Canada); Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB T1K 3M4 (Canada); Zaz, Zaid [Department of Electronics and Communication Engineering, University of Kashmir, Srinagar, Kashmir, 190006 (India); Ali, Ahmed Farag [Department of Physics, Faculty of Science, Benha University, Benha, 13518 (Egypt); Raza, Jamil [Department of Physics, International Islamic University, H-10 Sector, Islamabad (Pakistan); Shah, Mushtaq B. [Department of Physics, National Institute of Technology, Srinagar, Kashmir, 190006 (India)
2016-12-10
In this paper, we will propose the most general form of the deformation of Heisenberg algebra motivated by the generalized uncertainty principle. This deformation of the Heisenberg algebra will deform all quantum mechanical systems. The form of the generalized uncertainty principle used to motivate these results will be motivated by the space fractional quantum mechanics, and non-locality in quantum mechanical systems. We also analyse a specific limit of this generalized deformation for one dimensional system, and in that limit, a nonlocal deformation of the momentum operator generates a local deformation of all one dimensional quantum mechanical systems. We analyse the low energy effects of this deformation on a harmonic oscillator, Landau levels, Lamb shift, and potential barrier. We also demonstrate that this deformation leads to a discretization of space.
Liao, Haijun; Li, Tao
2011-11-30
We study the ground state phase diagram of the bilayer Heisenberg model on a square lattice with a bosonic resonating valence bond (RVB) wavefunction. The wavefunction has the form of a Gutzwiller projected Schwinger boson mean-field ground state and involves two variational parameters. We find the wavefunction provides an accurate description of the system on both sides of the quantum phase transition. In particular, through the analysis of the spin structure factor, ground state fidelity susceptibility and the Binder moment ratio Q(2), a continuous transition from the antiferromagnetic ordered state to the quantum disordered state is found at the critical coupling of α(c) = J(⊥)/J(∥) ≈ 2.62, in good agreement with the result of quantum Monte Carlo simulation. The critical exponent estimated from the finite size scaling analysis (1/ν ≈ 1.4) is consistent with that of the classical 3D Heisenberg universality class.
Un-equivalency theorem between deformed and undeformed Heisenberg-Weyl's algebras
International Nuclear Information System (INIS)
Zhang Jianzu
2006-01-01
Two fundamental issues about the relation between the deformed Heisenberg-Weyl algebra in noncommutative space and the undeformed one in commutative space are elucidated. First the un-equivalency theorem between two algebras is proved: the deformed algebra related to the undeformed one by a non-orthogonal similarity transformation is explored; furthermore, non-existence of a unitary similarity transformation which transforms the deformed algebra to the undeformed one is demonstrated. Secondly the uniqueness of realizing the deformed phase space variables via the undeformed ones is elucidated: both the deformed Heisenberg-Weyl algebra and the deformed bosonic algebra should be maintained under a linear transformation between two sets of phase space variables which fixes that such a linear transformation is unique. Elucidation of this un-equivalency theorem has basic meaning both in theory and experiment
Heisenberg uncertainty principle and light squeezing in quantum nanoantennas and electric circuits
Slepyan, Gregory Ya.
2016-10-01
The Heisenberg uncertainty principle is one of the cornerstones of quantum mechanics. We show that the observable values of the electromagnetic field in the far- and near-field zones emitted by the quantum nanoantenna are coupled via uncertainty relations of the Heisenberg type. The similar uncertainty inequalities are obtained for the electric currents in the different branches of the quantum networks. Based on these, we predict the mechanism of high-level squeezing of light in the quantum antennas. We show that this mechanism is highly directive. The strong values of squeezing are reaching in the narrow directions of high emission (tops of the main lobes of the radiation pattern). We also discuss the quantum noise manifestation in nanoelectronics and nanophotonics from the point of the electromagnetic compatibility of nanoelectronic devices, densely placed in the limited areas of space.
International Nuclear Information System (INIS)
Masood, Syed; Faizal, Mir; Zaz, Zaid; Ali, Ahmed Farag; Raza, Jamil; Shah, Mushtaq B.
2016-01-01
In this paper, we will propose the most general form of the deformation of Heisenberg algebra motivated by the generalized uncertainty principle. This deformation of the Heisenberg algebra will deform all quantum mechanical systems. The form of the generalized uncertainty principle used to motivate these results will be motivated by the space fractional quantum mechanics, and non-locality in quantum mechanical systems. We also analyse a specific limit of this generalized deformation for one dimensional system, and in that limit, a nonlocal deformation of the momentum operator generates a local deformation of all one dimensional quantum mechanical systems. We analyse the low energy effects of this deformation on a harmonic oscillator, Landau levels, Lamb shift, and potential barrier. We also demonstrate that this deformation leads to a discretization of space.
Excitation of bond-alternating spin-1/2 Heisenberg chains by tunnelling electrons
International Nuclear Information System (INIS)
Gauyacq, J-P; Lorente, N
2014-01-01
Inelastic electron tunneling spectra (IETS) are evaluated for spin-1/2 Heisenberg chains showing different phases of their spin ordering. The spin ordering is controlled by the value of the two different Heisenberg couplings on the two sides of each of the chain's atoms (bond-alternating chains). The perfect anti-ferromagnetic phase, i.e. a unique exchange coupling, marks a topological quantum phase transition (TQPT) of the bond-alternating chain. Our calculations show that the TQPT is recognizable in the excited states of the chain and hence that IETS is in principle capable of discriminating the phases. We show that perfectly symmetric chains, such as closed rings mimicking infinite chains, yield the same spectra on both sides of the TQPT and IETS cannot reveal the nature of the spin phase. However, for finite size open chains, both sides of the TQPT are associated with different IETS spectra, especially on the edge atoms, thus outlining the transition. (paper)
A convolution type characterization for Lp - multipliers for the Heisenberg group
Directory of Open Access Journals (Sweden)
R. Radha
2007-01-01
Full Text Available It is well known that if m is an Lp - multiplier for the Fourier transform on ℝn(1
Heisenberg group Hn. Though this result is already known in generality for amenable groups, a simple proof is provided in this paper.
Rangelov, Josiph Mladenov
2000-01-01
The object of this paper is to discuss the physical interpretation of quantum behaviour of Schrodinger electron (SchEl) and bring to light on the cause for the Heisenberg convenient operator way of its describing, using the nonrelativistic quantum mechanics laws and its mathematical results. We describe the forced stochastically diverse circular oscillation motion, created by force of the electrical interaction of the SchEl's elementary electric charge with the electric intensity of the resul...
Chiral-glass transition and replica symmetry breaking of a three-dimensional Heisenberg spin glass
Hukushima, K.; Kawamura, H.
2000-01-01
Extensive equilibrium Monte Carlo simulations are performed for a three-dimensional Heisenberg spin glass with the nearest-neighbor Gaussian coupling to investigate its spin-glass and chiral-glass orderings. The occurrence of a finite-temperature chiral-glass transition without the conventional spin-glass order is established. Critical exponents characterizing the transition are different from those of the standard Ising spin glass. The calculated overlap distribution suggests the appearance ...
Analytical results for entanglement in the five-qubit anisotropic Heisenberg model
International Nuclear Information System (INIS)
Wang Xiaoguang
2004-01-01
We solve the eigenvalue problem of the five-qubit anisotropic Heisenberg model, without use of Bethe's ansatz, and give analytical results for entanglement and mixedness of two nearest-neighbor qubits. The entanglement takes its maximum at Δ=1 (Δ>1) for the case of zero (finite) temperature with Δ being the anisotropic parameter. In contrast, the mixedness takes its minimum at Δ=1 (Δ>1) for the case of zero (finite) temperature
Topological basis realization for BMW algebra and Heisenberg XXZ spin chain model
Liu, Bo; Xue, Kang; Wang, Gangcheng; Liu, Ying; Sun, Chunfang
2015-04-01
In this paper, we study three-dimensional (3D) reduced Birman-Murakami-Wenzl (BMW) algebra based on topological basis theory. Several examples of BMW algebra representations are reviewed. We also discuss a special solution of BMW algebra, which can be used to construct Heisenberg XXZ model. The theory of topological basis provides a useful method to solve quantum spin chain models. It is also shown that the ground state of XXZ spin chain is superposition state of topological basis.
Critical behavior in a random field classical Heisenberg model for amorphous systems
International Nuclear Information System (INIS)
Albuquerque, Douglas F. de; Alves, Sandro Roberto L.; Arruda, Alberto S. de
2005-01-01
By using the differential operator technique and the effective field theory scheme, the critical behavior of amorphous classical Heisenberg ferromagnet of spin-1/2 in a random field is studied. The phase diagram in the T-H and T-α planes on a simple cubic lattice for a cluster with two spins is obtained. Tricritical points, reentrant phenomena and influence of the random field and amorphization on the transition temperature are discussed
Renormalization group treatment for spin waves in the randomly disordered Heisenberg chain
International Nuclear Information System (INIS)
Chaves, C.M.; Koiller, B.
1983-03-01
Local densities of states in the randomly disordered binary quantum Heisenberg chain using a generalization of a recently developed approach based on renormalization group ideas are calculated. It envolves decimating alternate apins along the chain in such a way as to obtain recursion relations to describe the renormalized set of Green's function equations of motion. The densities of states are richly structured, indicating that the method takes into account compositional fluctuations of arbitrary range. (Author) [pt
Sembiring, N.; Panjaitan, N.; Angelita, S.
2018-02-01
PT. XYZ is a company owned by non-governmental organizations engaged in the field of production of rubber processing becoming crumb rubber. Part of the production is supported by some of machines and interacting equipment to achieve optimal productivity. Types of the machine that are used in the production process are Conveyor Breaker, Breaker, Rolling Pin, Hammer Mill, Mill Roll, Conveyor, Shredder Crumb, and Dryer. Maintenance system in PT. XYZ is corrective maintenance i.e. repairing or replacing the engine components after the crash on the machine. Replacement of engine components on corrective maintenance causes the machine to stop operating during the production process is in progress. The result is in the loss of production time due to the operator must replace the damaged engine components. The loss of production time can impact on the production targets which were not reached and lead to high loss costs. The cost for all components is Rp. 4.088.514.505. This cost is really high just for maintaining a Mill Roll Machine. Therefore PT. XYZ is needed to do preventive maintenance i.e. scheduling engine components and improving maintenance efficiency. The used methods are Reliability Engineering and Maintenance Value Stream Mapping (MVSM). The needed data in this research are the interval of time damage to engine components, opportunity cost, labor cost, component cost, corrective repair time, preventive repair time, Mean Time To Opportunity (MTTO), Mean Time To Repair (MTTR), and Mean Time To Yield (MTTY). In this research, the critical components of Mill Roll machine are Spier, Bushing, Bearing, Coupling and Roll. Determination of damage distribution, reliability, MTTF, cost of failure, cost of preventive, current state map, and future state map are done so that the replacement time for each critical component with the lowest maintenance cost and preparation of Standard Operation Procedure (SOP) are developed. For the critical component that has been
Directory of Open Access Journals (Sweden)
Riza Ovita Risqi
2015-05-01
karyawan. Penelitian ini bertujuan untuk mengetahui besar pengaruh kepuasan kerja dan beban kerja terhadap kinerja karyawan Perusahaan XYZ. Beban kerja dipengaruhi oleh lingkungan kerja. Metode yang digunakan dalam penelitian adalah pendekatan Kansei Engineering. Kansei Engineering merupakan metode yang digunakan untuk mengolah nilai Kansei sebagai input menjadi atribut sistem kerja baru sebagai outputnya. Selain itu metode ini juga digunakan untuk mengetahui gap antara respon verbal dan non-verbal. Nilai Kansei diperoleh melalui wawancara yang disertai dengan pemutaran video sebagai sumber imajinasi karyawan. Hasil dari kuesioner kepuasan dan pengukuran beban kerja kemudian dianalisis menggunakan regresi berganda dengan hasil kuesioner kinerja. Input dari penelitian adalah faktor kepuasan kerja dan beban kerja, sedangkan output adalah kinerja karyawan. Hasil penelitian diperoleh nilai r square yaitu diketahui bahwa nilai korelasi model regresi linier berganda ini adalah sebesar 77,5%, sedangkan adjusted r square sebesar 44,1% menunjukkan bahwa kinerja karyawan variabel Y dapat dijelaskan oleh variabel X yang meliputi faktor ﬁsiologis, keselamatan dan keamanan, sosial, penghargaan, aktualisasi diri, dan beban kerja sebesar 44,1%. Persentase sisanya sebesar 55,9% dijelaskan oleh variabel lainnya. Kata kunci: Kepuasan kerja, kinerja karyawan, Kansei Engineering, Kansei word
Directory of Open Access Journals (Sweden)
Roni Kurniawan
2014-12-01
Full Text Available Education has a strategic role in preparing qualified future generations. Education has business potential that is reliable and promising, considering the timeless education, as well as the expectations of every parent to their children to have the access to the best education. Evolving world of education today isdemonstrated by the high rate of growth of established schools, especially private schools. Parents today are more savvy and critical in determining the best school for their children, taking into account various aspects, ranging from excellent schools, curriculum, learning systems, the facility to activities that make their children good personality and smart. A more selective attitude that makes private education institutions now have to be more innovative in order to compete. This study was conducted to determine how big the Service Quality and Information Systems School, affect Customer Satisfaction, which will have an impact on Customer Loyalty (Case Study at XYZ School. The study was conducted with data collection techniques in the form of questionnaires toa total of 100 respondents, using descriptive statistical calculations, where the data were analyzed by using electronic data processing methods with the support of SPSS 17.0 To measure the influence of independent variables on the dependent variable, then the path analysis (path analysis was used. The results showed that the Service Quality and Information Systems School were contributing together, and significant in Customer Satisfaction. Service Quality, Information Systems and Customer Satisfaction of school together contributesignificantly to Customer Loyalty.
IT Audit of IT Service Provider Using COBIT 4.1 Framework: Case Study at PT. XYZ
Directory of Open Access Journals (Sweden)
Muhammad Malik Hakim
2017-11-01
Full Text Available IT service providers often campaign for the importance of having a high level of IT maturity to its customers. However, not all IT companies have a high commitment to IT management within their own organisation. As a case study, this paper attempts to measure the IT maturity level of PT. XYZ that now is a growing IT services provider. Data collection is done by interview, document study, and direct field observation. The measurement of IT maturity level is conducted using 4 domains of COBIT 4.1 Framework, consists of Plan and Organize (PO, Deliver and Support (DS, Acquire and Implement (AI, and Monitor and Evaluate (ME. The result shows a value of 2.5 which indicates that IT maturity level is at level 2 (Repeatable but Intuitive which means low enough for companies that should have a high awareness of IT governance and commitment. This study shows that the level of IT maturity in IT service provider is not always as high as its campaign.
Directory of Open Access Journals (Sweden)
Fila Dristiana
2015-10-01
Full Text Available PT. XYZ is one of the manufactures of parmacheutical. Problems which often appeared are surplus and shortage material. Inventory material control not optimum because order only esimate. With exponential smoothing method can be devise of demand next period and EOQ Probabilistic for to know economic order quantity, total safety stock and reorder point so can minimization inventory cost. Purpose of research are to know exponential smoothing method what representatif for manufacture and give recomendation of this research. Results of research are exponential smoothing method representatif for manufacture and EOQ probabilistic method for Antalgin, Paracetamol and Piroxicam material are economic order quantity in the amount of 313 kg, 928 kg and 33 kg, safety stock 160 kg, 403 kg and 2kg and reorder point 325 kg, 1080 kg dan 14 kg. So total inventory cost of Antalgin, Paracetamol and Piroxicam material in the amount of Rp.3.847.146, Rp.5.025.081 and Rp.1.932.255.
Entangling capabilities of symmetric two-qubit gates
Indian Academy of Sciences (India)
2014-07-25
Jul 25, 2014 ... Our work addresses the problem of generating maximally entangled two spin-1/2 (qubit) symmetric states using NMR, NQR, Lipkin–Meshkov–Glick Hamiltonians. Time evolution of such Hamiltonians provides various logic gates which can be used for quantum processing tasks. Pairs of spin-1/2s have ...
Entangling capabilities of symmetric two-qubit gates
Indian Academy of Sciences (India)
two spin-1/2 symmetric states which belong to a subspace spanned by the angular momentum basis. {|j = 1,μ〉; μ = +1, 0, −1}. Our technique relies on the decomposition of a Hamiltonian in terms of SU(3) basis matrices. In this context, we define a set of linearly independent, traceless, Hermitian operators which provides an ...
Fisher information of accelerated two-qubit systems
Metwally, N.
2018-02-01
In this paper, Fisher information for an accelerated system initially prepared in the X-state is discussed. An analytical solution, which consists of three parts: classical, the average over all pure states and a mixture of pure states, is derived for the general state and for Werner state. It is shown that the Unruh acceleration has a depleting effect on the Fisher information. This depletion depends on the degree of entanglement of the initial state settings. For the X-state, for some intervals of Unruh acceleration, the Fisher information remains constant, irrespective to the Unruh acceleration. In general, the possibility of estimating the state’s parameters decreases as the acceleration increases. However, the precision of estimation can be maximized for certain values of the Unruh acceleration. We also investigate the contribution of the different parts of the Fisher information on the dynamics of the total Fisher information.
Entangling capabilities of symmetric two-qubit gates
Indian Academy of Sciences (India)
states from some suitably chosen initial separable states in terms of their entangling power. Keywords. Quantum entanglement; SU(3) generators; entangling power. PACS No. 03.65.Ud. 1. Introduction. In the last few years, there has been considerable increase in experimental activity aiming to create entangled quantum ...
Directory of Open Access Journals (Sweden)
Muhammad Ryan Natasaputra
2015-11-01
Full Text Available ABSTRAK Pabrik ban XYZ yang berlokasi di Jawa Barat merupakan salah satu industri ban yang telah memiliki komitmen untuk meningkatkan kinerja lingkungan dengan menerapkan Sistem Manajemen Lingkungan (SML ISO 14001. Tujuan dari penelitian ini adalah untuk mengevaluasi efektivitas penerapan SML ISO 14001 berdasarkan kinerja manajemen, kinerja lingkungan, dan kesesuaian dengan sertifikasi Occupational Health and Safety Assessment Series (OHSAS 18001. Penelitian ini dilakukan dengan dua metode, yaitu pengumpulan data primer melalui pemantauan lapang dan data sekunder melalui dokumen-dokumen yang berhubungan dengan SML serta data hasil pengukuran Aspek Lingkungan Penting (ALP. Data tersebut dievaluasi dan dibandingkan dengan SNI 19-14001-2005, program lingkungan perusahaan, serta peraturan perundangan yang berlaku agar diketahui efektivitas penerapan SML ISO 14001. Hasil penelitian menunjukkan bahwa kebijakan lingkungan telah sesuai dengan tiga komitmen utama dalam SNI 19-14001-2005. Prosedur identifikasi dan klasifikasi ALP telah dilaksanakan dengan metode penilaian terhadap empat kriteria yang dibuat oleh pihak manajemen pabrik ban. Data hasil pengukuran ALP yang dievaluasi meliputi kebisingan, debu, limbah cair industri, dan penggunaan air. Efektivitas penerapan SML ISO 14001 di pabrik ban melalui hasil penilaian kinerja manajemen sebesar 80% dan kinerja lingkungan dari data hasil pengukuran ALP sebesar 81,3%, secara umum membuktikan bahwa penerapan SML ISO 14001 dengan nilai pencapaian sebesar 80,7% telah efektif dalam memenuhi tujuan dari komitmen pencegahan pencemaran, penerapan program lingkungan, dan peraturan perundangan yang berlaku. Ketidaksesuaian disebabkan oleh masalah komunikasi, kesadaran karyawan, dan kelayakan teknis. Dalam hal keselamatan dan kesehatan kerja terdapat integrasi dengan OHSAS 18001 melalui penggunaan Alat Pelindung Diri (APD dan prosedur tanggap darurat. ABSTRACT XYZ tyre factory in West Java is one of the tyre
Rodrigues, F. C.; de Souza, S. M.; Rojas, Onofre
2017-04-01
Motivated by the recent discoveries of some compounds such as the Bi2Fe4O9 which crystallizes in an orthorhombic crystal structure with the Fe3+ ions, and iron-based oxyfluoride Bi4Fe5O13 F compounds following the pattern of Cairo pentagonal structure, among some other compounds. We propose a model for one stripe of the Cairo pentagonal Ising-Heisenberg lattice, one of the edges of a pentagon is different, and this edge will be associated with a Heisenberg exchange interaction, while the Ising exchange interactions will associate the other edges. We study the phase transition at zero temperature, illustrating five phases: a ferromagnetic phase (FM), a dimer antiferromagnetic (DAF), a plaquette antiferromagnetic (PAF), a typical antiferromagnetic (AFM) and a peculiar frustrated phase (FRU) where two types of frustrated states with the same energy coexist. To obtain the partition function of this model, we use the transfer matrix approach and following the eight vertex model notation. Using this result we discuss the specific heat, internal energy and entropy as a function of the temperature, and we can observe some unexpected behavior in the low-temperature limit, such as anomalous double peak in specific heat due to the existence of three phase (FRU, PAF(AFM) and FM) transitions occurring in a close region to each other. Consequently, the low-lying energy thermal excitation generates this double anomalous peak, and we also discuss the internal energy at the low temperature limit, where this double peak curve occurs. Some properties of our result were compared with two dimensional Cairo pentagonal lattices, as well as orthogonal dimer plaquette Ising-Heisenberg chain.
Quantum Monte Carlo simulation for S=1 Heisenberg model with uniaxial anisotropy
International Nuclear Information System (INIS)
Tsukamoto, Mitsuaki; Batista, Cristian; Kawashima, Naoki
2007-01-01
We perform quantum Monte Carlo simulations for S=1 Heisenberg model with an uniaxial anisotropy. The system exhibits a phase transition as we vary the anisotropy and a long range order appears at a finite temperature when the exchange interaction J is comparable to the uniaxial anisotropy D. We investigate quantum critical phenomena of this model and obtain the line of the phase transition which approaches a power-law with logarithmic corrections at low temperature. We derive the form of logarithmic corrections analytically and compare it to our simulation results
Gong, Jia-Min; Tang, Qi; Sun, Yu-Hang; Qiao, Lin
2015-03-01
We studied the trace distance, the Hellinger distance, and the Bures distance geometric quantum discords (GQDs) for a two-spin Heisenberg XX chain with the Dzyaloshinsky-Moriya (DM) interaction and the external magnetic fields. We found that considerable enhancement of the GQDs can be achieved by introducing the DM interaction, and their maxima were obtained when the strength of the DM interaction approaches infinity. The external magnetic fields and the increase of the temperature can also enhance the GQDs to some extent during certain specific parameter regions.
Event-chain algorithm for the Heisenberg model: Evidence for z≃1 dynamic scaling.
Nishikawa, Yoshihiko; Michel, Manon; Krauth, Werner; Hukushima, Koji
2015-12-01
We apply the event-chain Monte Carlo algorithm to the three-dimensional ferromagnetic Heisenberg model. The algorithm is rejection-free and also realizes an irreversible Markov chain that satisfies global balance. The autocorrelation functions of the magnetic susceptibility and the energy indicate a dynamical critical exponent z≈1 at the critical temperature, while that of the magnetization does not measure the performance of the algorithm. We show that the event-chain Monte Carlo algorithm substantially reduces the dynamical critical exponent from the conventional value of z≃2.
A mean field study of the quasi-one-dimensional antiferromagnetic anisotropic Heisenberg model
International Nuclear Information System (INIS)
Benyoussef, A.
1996-10-01
The effect of the chain and the dimer anisotropies on the ground state energy and the energy gap of the spin-1/2 quasi-one-dimensional antiferromagnetic Heisenberg model is investigated using a mean field theory. The dependence of the magnetization and the effective hopping parameters on the anisotropy α xy (=J xy perpendicular /J xy parallel ) are presented for several values of the chain anisotropy. However, such a system exhibits a transition from antiferromagnetic ordered to disordered phases for arbitrary chain anisotropy and dimer anisotropy. (author). 22 refs, 11 figs
Meda Inequality for Rearrangements of the Convolution on the Heisenberg Group and Some Applications
Directory of Open Access Journals (Sweden)
V. S. Guliyev
2009-01-01
Full Text Available The Meda inequality for rearrangements of the convolution operator on the Heisenberg group ℍn is proved. By using the Meda inequality, an O'Neil-type inequality for the convolution is obtained. As applications of these results, some sufficient and necessary conditions for the boundedness of the fractional maximal operator MΩ,α and fractional integral operator IΩ,α with rough kernels in the spaces Lp(ℍn are found. Finally, we give some comments on the extension of our results to the case of homogeneous groups.
Quantum correlations and limit cycles in the driven-dissipative Heisenberg lattice
Owen, E. T.; Jin, J.; Rossini, D.; Fazio, R.; Hartmann, M. J.
2018-04-01
Driven-dissipative quantum many-body systems have attracted increasing interest in recent years as they lead to novel classes of quantum many-body phenomena. In particular, mean-field calculations predict limit cycle phases, slow oscillations instead of stationary states, in the long-time limit for a number of driven-dissipative quantum many-body systems. Using a cluster mean-field and a self-consistent Mori projector approach, we explore the persistence of such limit cycles as short range quantum correlations are taken into account in a driven-dissipative Heisenberg model.
Spin-wave analysis of the XXZ Heisenberg model with Dzyaloshinskii-Moriya interaction
International Nuclear Information System (INIS)
Benyoussef, A.; Boubekri, A.; Ez-Zahraouy, H.
1998-08-01
The effect of the Dzyaloshinskii-Moriya interaction on the stability of the Neel phase and the energy gap for the XXZ Heisenberg model on a d-dimensional hypercubic lattice is investigated using the linear spin-wave theory. In one-dimension, the disordered phase disappears above a critical value of the spin-axis anisotropy. In two-dimension, the instability of the Neel order occurs below a critical value of the easy-axis anisotropy. We find that for all d-dimensional systems, the energy gap vanishes above a critical value of the DM interaction. (author)
Generalized Heisenberg Algebras, SUSYQM and Degeneracies: Infinite Well and Morse Potential
Directory of Open Access Journals (Sweden)
Véronique Hussin
2011-03-01
Full Text Available We consider classical and quantum one and two-dimensional systems with ladder operators that satisfy generalized Heisenberg algebras. In the classical case, this construction is related to the existence of closed trajectories. In particular, we apply these results to the infinite well and Morse potentials. We discuss how the degeneracies of the permutation symmetry of quantum two-dimensional systems can be explained using products of ladder operators. These products satisfy interesting commutation relations. The two-dimensional Morse quantum system is also related to a generalized two-dimensional Morse supersymmetric model. Arithmetical or accidental degeneracies of such system are shown to be associated to additional supersymmetry.
Motion of a magnetic soliton about a lattice soliton in a Heisenberg chain
International Nuclear Information System (INIS)
Nayyar, A.H.; Murtaza, G.
1981-08-01
As an example of interaction between two solitons belonging to different species, a semiclassical study of the nonlinear dynamics of a coupled magnon-phonon system in a one-dimensional Heisenberg ferromagnet is made, where both the lattice and the spin systems are taken with their respective nonlinear interactions. The lattice soliton is shown to introduce spatial inhomogeneities into the propagation of the magnetic soliton resulting in (a) the trapping of the magnetic soliton in the harmonic field of the lattice soliton and (b) the amplitude and the width of the magnetic soliton becoming time-dependent. (author)
Excitations of breathers and rogue wave in the Heisenberg spin chain
Qi, Jian-Wen; Duan, Liang; Yang, Zhan-Ying; Yang, Wen-Li
2018-01-01
We study the excitations of breathers and rogue wave in a classical Heisenberg spin chain with twist interaction, which is governed by a fourth-order integrable nonlinear Schrödinger equation. The dynamics of these waves have been extracted from an exact solution. In particular, the corresponding existence conditions based on the parameters of perturbation wave number K, magnon number N, background wave vector ks and amplitude c are presented explicitly. Furthermore, the characteristics of magnetic moment distribution corresponding to these nonlinear waves are also investigated in detail. Finally, we discussed the state transition of three types nonlinear localized waves under the different excitation conditions.
Monte Carlo study of four-spinon dynamic structure function in antiferromagnetic Heisenberg model
International Nuclear Information System (INIS)
Si-Lakhal, B.; Abada, A.
2003-11-01
Using Monte Carlo integration methods, we describe the behavior of the exact four-s pinon dynamic structure function S 4 in the antiferromagnetic spin 1/2 Heisenberg quantum spin chain as a function of the neutron energy ω and momentum transfer k. We also determine the fourspinon continuum, the extent of the region in the (k, ω) plane outside which S 4 is identically zero. In each case, the behavior of S 4 is shown to be consistent with the four-spinon continuum and compared to the one of the exact two-spinon dynamic structure function S 2 . Overall shape similarity is noted. (author)
Critical behaviour of magnetic thin film with Heisenberg spin-S model
International Nuclear Information System (INIS)
Masrour, R.; Hamedoun, M.; Bouslykhane, K.; Hourmatallah, A.; Benzakour, N.; Benyoussef, A.
2009-01-01
The magnetic properties of a ferromagnetic thin film of face centered cubic (FCC) lattice with Heisenberg spin-S are examined using the high-temperature series expansions technique extrapolated with Pade approximations method. The critical reduced temperature of the system τ c is studied as function of thickness of the film and the exchange interactions in the bulk, and within the surfaces J b , J s and J perpendicular respectively. A critical value of surface exchange interaction above which surface magnetism appears is obtained. The dependence of the reduced critical temperature on the film thickness L has been investigated.
Energy Technology Data Exchange (ETDEWEB)
Belgiorno, Francesco [Politecnico di Milano, Dipartimento di Matematica, Milano (Italy); INdAM-GNFM, Milano (Italy); Cacciatori, Sergio L. [Universita dell' Insubria, Department of Science and High Technology, Como (Italy); INFN sezione di Milano, Milano (Italy); Dalla Piazza, Francesco [Universita ' ' La Sapienza' ' , Dipartimento di Matematica, Roma (Italy); Doronzo, Michele [Universita dell' Insubria, Department of Science and High Technology, Como (Italy)
2016-06-15
We investigate the quantisation in the Heisenberg representation of a model which represents a simplification of the Hopfield model for dielectric media, where the electromagnetic field is replaced by a scalar field φ and the role of the polarisation field is played by a further scalar field ψ. The model, which is quadratic in the fields, is still characterised by a non-trivial physical content, as the physical particles correspond to the polaritons of the standard Hopfield model of condensed matter physics. Causality is also taken into account and a discussion of the standard interaction representation is also considered. (orig.)
Kuzmak, A. R.; Tkachuk, V. M.
2013-04-01
We study the quantum brachistochrone evolution for a system of two spins-\\frac{1}{2} described by an anisotropic Heisenberg Hamiltonian without zx, zy interacting couplings in magnetic field directed along the z-axis. This Hamiltonian realizes quantum evolution in two subspaces spanned by |↑↑>, |↓↓> and |↑↓>, |↓↑> separately and allows us to consider the brachistochrone problem on each subspace separately. Using the evolution operator for this Hamiltonian we generate quantum gates, namely an entangler gate, SWAP gate, iSWAP gate etc.
De La Rosa Gomez, Alejandro; MacKay, Niall; Regelskis, Vidas
2017-04-01
We present a general method of folding an integrable spin chain, defined on a line, to obtain an integrable open spin chain, defined on a half-line. We illustrate our method through two fundamental models with sl2 Lie algebra symmetry: the Heisenberg XXX and the Inozemtsev hyperbolic spin chains. We obtain new long-range boundary Hamiltonians and demonstrate that they exhibit Yangian symmetries, thus ensuring integrability of the models we obtain. The method presented provides a ;bottom-up; approach for constructing integrable boundaries and can be applied to any spin chain model.
A quaternionic map for the steady states of the Heisenberg spin-chain
International Nuclear Information System (INIS)
Mehta, Mitaxi P.; Dutta, Souvik; Tiwari, Shubhanshu
2014-01-01
We show that the steady states of the classical Heisenberg XXX spin-chain in an external magnetic field can be found by iterations of a quaternionic map. A restricted model, e.g., the xy spin-chain is known to have spatially chaotic steady states and the phase space occupied by these chaotic states is known to go through discrete changes as the field strength is varied. The same phenomenon is studied for the xxx spin-chain. It is seen that in this model the phase space volume varies smoothly with the external field.
The low-temperature phase of the Heisenberg antiferromagnet in a fermionic representation
International Nuclear Information System (INIS)
Azakov, S.; Dilaver, M.; Oztas, A.M.
1999-09-01
Thermal properties of the ordered phase of the spin 1/2 isotropic Heisenberg Antiferromagnet on a d-dimensional hypercubical lattice are studied within the fermionic representation when the constraint of a single occupancy condition is taken into account by the method suggested by Popov and Fedotov. Using a saddle point approximation in the path integral approach we discuss not only the leading order but also the fluctuations around the saddle point at one-loop level. The influence of taking into account the single occupancy condition is discussed at all steps. (author)
Domain growth by isothermal aging in 3D Ising and Heisenberg spin glasses.
Jönsson, P E; Yoshino, H; Nordblad, P; Aruga Katori, H; Ito, A
2002-06-24
Nonequilibrium dynamics of three-dimensional model spin glasses, the Ising system Fe0.50Mn0.50TiO3 and the Heisenberg-like system Ag(11 at % Mn), has been investigated by measurements of the isothermal time decay of the low frequency ac susceptibility after a quench from the paramagnetic to the spin-glass phase. It is found that the relaxation data measured at different temperatures can be scaled according to predictions from the droplet scaling model, provided that critical fluctuations are accounted for in the analyses.
A dual view of the 3d Heisenberg model and the abelian projection
Di Giacomo, A.; Martelli, D.; Paffuti, G.
1999-01-01
The Heisenberg model in 3d is studied from a dual point of view. It is shown that it can have vortex configurations, carrying a conserved charge(U(1) symmetry). Vortices condens in the disordered phase. A disorder parameter $\\leftangle\\mu\\rightangle$ is defined dual to the magnetization $\\leftangle\\vec n\\rightangle$, which signals condensation of vortices, i.e. spontaneous breaking of the dual U(1) symmetry. This study sheds light on the procedure known as abelian projection in non abelian ga...
A quaternionic map for the steady states of the Heisenberg spin-chain
Energy Technology Data Exchange (ETDEWEB)
Mehta, Mitaxi P., E-mail: mitaxi.mehta@ahduni.edu.in [IICT, Ahmedabad University, Opp. IIM, Navrangpura, Ahmedabad (India); Dutta, Souvik; Tiwari, Shubhanshu [BITS-Pilani, K.K. Birla Goa campus, Goa (India)
2014-01-17
We show that the steady states of the classical Heisenberg XXX spin-chain in an external magnetic field can be found by iterations of a quaternionic map. A restricted model, e.g., the xy spin-chain is known to have spatially chaotic steady states and the phase space occupied by these chaotic states is known to go through discrete changes as the field strength is varied. The same phenomenon is studied for the xxx spin-chain. It is seen that in this model the phase space volume varies smoothly with the external field.
J1x-J1y-J2 square-lattice anisotropic Heisenberg model
Pires, A. S. T.
2017-08-01
The spin one Heisenberg model with an easy-plane single-ion anisotropy and spatially anisotropic nearest-neighbor coupling, frustrated by a next-nearest neighbor interaction, is studied at zero temperature using a SU(3) Schwinger boson formalism (sometimes also referred to as flavor wave theory) in a mean field approximation. The local constraint is enforced by introducing a Lagrange multiplier. The enlarged Hilbert space of S = 1 spins lead to a nematic phase that is ubiquitous to S = 1 spins with single ion anisotropy. The phase diagram shows two magnetically ordered phase, separated by a quantum paramagnetic (nematic) phase.
International Nuclear Information System (INIS)
Belgiorno, Francesco; Cacciatori, Sergio L.; Dalla Piazza, Francesco; Doronzo, Michele
2016-01-01
We investigate the quantisation in the Heisenberg representation of a model which represents a simplification of the Hopfield model for dielectric media, where the electromagnetic field is replaced by a scalar field φ and the role of the polarisation field is played by a further scalar field ψ. The model, which is quadratic in the fields, is still characterised by a non-trivial physical content, as the physical particles correspond to the polaritons of the standard Hopfield model of condensed matter physics. Causality is also taken into account and a discussion of the standard interaction representation is also considered. (orig.)
Ground state properties of a spin chain within Heisenberg model with a single lacking spin site
International Nuclear Information System (INIS)
Mebrouki, M.
2011-01-01
The ground state and first excited state energies of an antiferromagnetic spin-1/2 chain with and without a single lacking spin site are computed using exact diagonalization method, within the Heisenberg model. In order to keep both parts of a spin chain with a lacking site connected, next nearest neighbors interactions are then introduced. Also, the Density Matrix Renormalization Group (DMRG) method is used, to investigate ground state energies of large system sizes; which permits us to inquire about the effect of large system sizes on energies. Other quantum quantities such as fidelity and correlation functions are also studied and compared in both cases. - Research highlights: → In this paper we compute ground state and first excited state energies of a spin chain with and without a lacking spin site. The next nearest neighbors are introduced with the antiferromagnetic Heisenberg spin-half. → Exact diagonalization is used for small systems, where DMRG method is used to compute energies for large systems. Other quantities like quantum fidelity and correlation are also computed. → Results are presented in figures with comments. → E 0 /N is computed in a function of N for several values of J 2 and for both systems. First excited energies are also investigated.
International Nuclear Information System (INIS)
Paulinelli, H G; De Souza, S M; Rojas, Onofre
2013-01-01
In this paper we explore the entanglement in an orthogonal dimer-plaquette Ising–Heisenberg chain, assembled between plaquette edges, also known as orthogonal dimer plaquettes. The quantum entanglement properties involving an infinite chain structure are quite important, not only because the mathematical calculation is cumbersome but also because real materials are well represented by infinite chains. Using the local gauge symmetry of this model, we are able to map onto a simple spin-1 like Ising and spin-1/2 Heisenberg dimer model with single effective ion anisotropy. Thereafter this model can be solved using the decoration transformation and transfer matrix approach. First, we discuss the phase diagram at zero temperature of this model, where we find five ground states, one ferromagnetic, one antiferromagnetic, one triplet–triplet disordered and one triplet–singlet disordered phase, beside a dimer ferromagnetic–antiferromagnetic phase. In addition, we discuss the thermodynamic properties such as entropy, where we display the residual entropy. Furthermore, using the nearest site correlation function it is possible also to analyze the pairwise thermal entanglement for both orthogonal dimers. Additionally, we discuss the threshold temperature of the entangled region as a function of Hamiltonian parameters. We find a quite interesting thin reentrance threshold temperature for one of the dimers, and we also discuss the differences and similarities for both dimers. (paper)
Verifying Heisenberg's error-disturbance relation using a single trapped ion.
Zhou, Fei; Yan, Leilei; Gong, Shijie; Ma, Zhihao; He, Jiuzhou; Xiong, Taiping; Chen, Liang; Yang, Wanli; Feng, Mang; Vedral, Vlatko
2016-10-01
Heisenberg's uncertainty relations have played an essential role in quantum physics since its very beginning. The uncertainty relations in the modern quantum formalism have become a fundamental limitation on the joint measurements of general quantum mechanical observables, going much beyond the original discussion of the trade-off between knowing a particle's position and momentum. Recently, the uncertainty relations have generated a considerable amount of lively debate as a result of the new inequalities proposed as extensions of the original uncertainty relations. We report an experimental test of one of the new Heisenberg's uncertainty relations using a single 40 Ca + ion trapped in a harmonic potential. By performing unitary operations under carrier transitions, we verify the uncertainty relation proposed by Busch, Lahti, and Werner (BLW) based on a general error-trade-off relation for joint measurements on two compatible observables. The positive operator-valued measure, required by the compatible observables, is constructed by single-qubit operations, and the lower bound of the uncertainty, as observed, is satisfied in a state-independent manner. Our results provide the first evidence confirming the BLW-formulated uncertainty at a single-spin level and will stimulate broad interests in various fields associated with quantum mechanics.
RVB signatures in the spin dynamics of the square-lattice Heisenberg antiferromagnet
Ghioldi, E. A.; Gonzalez, M. G.; Manuel, L. O.; Trumper, A. E.
2016-03-01
We investigate the spin dynamics of the square-lattice spin-\\frac{1}{2} Heisenberg antiferromagnet by means of an improved mean-field Schwinger boson calculation. By identifying both, the long-range Néel and the RVB-like components of the ground state, we propose an educated guess for the mean-field magnetic excitation consisting on a linear combination of local and bond spin flips to compute the dynamical structure factor. Our main result is that when this magnetic excitation is optimized in such a way that the corresponding sum rule is fulfilled, we recover the low- and high-energy spectral weight features of the experimental spectrum. In particular, the anomalous spectral weight depletion at (π,0) found in recent inelastic neutron scattering experiments can be attributed to the interference of the triplet bond excitations of the RVB component of the ground state. We conclude that the Schwinger boson theory seems to be a good candidate to adequately interpret the dynamic properties of the square-lattice Heisenberg antiferromagnet.
Magnetic properties of the spin S = 1/2 Heisenberg chain with hexamer modulation of exchange.
Naseri, M Shahri; Japaridze, G I; Mahdavifar, S; Shayesteh, S Farjami
2012-03-21
We consider the spin-1/2 Heisenberg chain with alternating spin exchange in the presence of additional modulation of exchange on odd bonds with period 3. We study the ground state magnetic phase diagram of this hexamer spin chain in the limit of very strong antiferromagnetic (AF) exchange on odd bonds using the numerical Lanczos method and bosonization approach. In the limit of strong magnetic field commensurate with the dominating AF exchange, the model is mapped onto an effective XXZ Heisenberg chain in the presence of uniform and spatially modulated fields, which is studied using the standard continuum-limit bosonization approach. In the absence of additional hexamer modulation, the model undergoes a quantum phase transition from a gapped phase into the only one gapless Lüttinger liquid (LL) phase by increasing the magnetic field. In the presence of hexamer modulation, two new gapped phases are identified in the ground state at magnetization equal to [Formula: see text] and [Formula: see text] of the saturation value. These phases reveal themselves also in the magnetization curve as plateaus at corresponding values of magnetization. As a result, the magnetic phase diagram of the hexamer chain shows seven different quantum phases, four gapped and three gapless, and the system is characterized by six critical fields which mark quantum phase transitions between the ordered gapped and the LL gapless phases. © 2012 IOP Publishing Ltd
Study of interacting fields in a canonical formalism in Heisenberg picture of quantum field theory
International Nuclear Information System (INIS)
RANAIVOSON, R.T.R.
2011-01-01
In this work, we have made a study on the canonical formalism of the quantum field theory. Our contribution has been the development of a study using the Heisenberg picture. We showed that this approach may be useful for the description of quantum dynamics of interacting fields in bounded states. Our approach is to start from the lagrangian density of a classical theory from which one deduce the classical evolution equations of the fields via Euler-Lagrange equation for fields and establish the expression of conserved quantities characterizing the dynamics using the Noether theorem. Passing to the canonical quantization, fields and quantities characterizing the dynamics become quantum operators and evolution equations become operatorial evolution equations in Heisenberg picture. Expressions of quantum observable are also deduced from the expressions of classical conserved quantities. After, we showed that using the properties of fields operators and quantum states vectors, one can deduce from the operatorial evolution equations, the evolution equations for the wave functions of fermions and the evolution equations of expectation values of boson fields. For the illustration, various studies were conducted: the case of electrodynamics, the case of a general gauge theory and the case of the Standard Model. [fr
The Design of Control Pulses for Heisenberg Always-On Qubit Models
Magyar, Rudolph
2015-03-01
One model for a universal quantum computer is a spin array with constant nearest neighbor interactions and a controlled unidirectional site-specific magnetic field to generate unitary transformations. This system can be described by a Heisenberg spin Hamiltonian and can be simulated for on the order of 50 spins. It has recently been shown that time-dependent density functional inspired methods may be used to relate various spin models of qubits to ones that may be easier to compute numerically allowing potentially the efficient simulation of greater numbers of spins. One of the challenges of such an agenda is the identification of control pulses that produce desired gate operations (CNOT and single qubit phase gates). We apply control theory to design a universal set of pulses for a Heisenberg always-on model Hamiltonian for a few qubits and compare to known pulses when available. We suggest how this approach may be useful to design control pulses in other realistic designs. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Security Administration under contract DE-AC04-94AL85000.
Neutron-scattering cross section of the S=1/2 Heisenberg triangular antiferromagnet
DEFF Research Database (Denmark)
Lefmann, K.; Hedegård, P.
1994-01-01
In this paper we use a Schwinger-boson mean-field approach to calculate the neutron-scattering cross section from the S = 1/2 antiferromagnet with nearest-neighbor isotropic Heisenberg interaction on a two-dimensional triangular lattice. We investigate two solutions for T = 0: (i) a state with lo...... no elastic, but a set of broader dispersive spin excitations around kappa almost-equal-to (1/2, 0) and around kappa almost-equal-to (1/3, 1/3) for omega/E(g) = 2.5-4. It should thus be possible to distinguish these two states in a neutron-scattering experiment.......In this paper we use a Schwinger-boson mean-field approach to calculate the neutron-scattering cross section from the S = 1/2 antiferromagnet with nearest-neighbor isotropic Heisenberg interaction on a two-dimensional triangular lattice. We investigate two solutions for T = 0: (i) a state with long......-range order resembling the Neel state and (ii) a resonating valence bond or ''spin liquid'' state with an energy gap, E(g) almost-equal-to 0.17J, for the elementary excitations (spinons). For solution (ii) the neutron cross section shows Bragg rods at kappa = K = (1/3, 1/3), whereas solution (ii) shows...
Kimchi, Itamar; Vishwanath, Ashvin
2014-01-01
The Kitaev-Heisenberg (KH) model has been proposed to capture magnetic interactions in iridate Mott insulators on the honeycomb lattice. We show that analogous interactions arise in many other geometries built from edge-sharing IrO6 octahedra, including the pyrochlore and hyperkagome lattices relevant to Ir2O4 and Na4Ir3O8, respectively. The Kitaev spin liquid exact solution does not generalize to these lattices. However, a different, exactly soluble point of the honeycomb lattice KH model, obtained by a four-sublattice transformation to a ferromagnet, generalizes to all of these lattices and even to certain additional further neighbor Heisenberg couplings. A Klein four-group ≅Z2×Z2 structure is associated with this mapping (hence Klein duality). A finite lattice admits the duality if a simple geometrical condition is met. This duality predicts fluctuation-free ordered states on these different 2D and 3D lattices, which are analogues of the honeycomb lattice KH stripy order. This result is used in conjunction with a semiclassical Luttinger-Tisza approximation to obtain phase diagrams for KH models on the different lattices. We also discuss a Majorana fermion based mean-field theory at the Kitaev point, which is exact on the honeycomb lattice, for the KH models on the different lattices. We attribute the rich behavior of these models to the interplay of geometric frustration and frustration induced by spin-orbit coupling.
Spin glass behavior of the antiferromagnetic Heisenberg model on scale free network
International Nuclear Information System (INIS)
Surungan, Tasrief; Zen, Freddy P; Williams, Anthony G
2015-01-01
Randomness and frustration are considered to be the key ingredients for the existence of spin glass (SG) phase. In a canonical system, these ingredients are realized by the random mixture of ferromagnetic (FM) and antiferromagnetic (AF) couplings. The study by Bartolozzi et al. [Phys. Rev. B73, 224419 (2006)] who observed the presence of SG phase on the AF Ising model on scale free network (SFN) is stimulating. It is a new type of SG system where randomness and frustration are not caused by the presence of FM and AF couplings. To further elaborate this type of system, here we study Heisenberg model on AF SFN and search for the SG phase. The canonical SG Heisenberg model is not observed in d-dimensional regular lattices for (d ≤ 3). We can make an analogy for the connectivity density (m) of SFN with the dimensionality of the regular lattice. It should be plausible to find the critical value of m for the existence of SG behaviour, analogous to the lower critical dimension (d l ) for the canonical SG systems. Here we study system with m = 2, 3, 4 and 5. We used Replica Exchange algorithm of Monte Carlo Method and calculated the SG order parameter. We observed SG phase for each value of m and estimated its corersponding critical temperature. (paper)
Constructing an entangled state in the Heisenberg picture for inflationary cosmology
Rostami, Abasalt; Firouzjaee, Javad T.
2018-03-01
The effects of the entanglement of the inflaton field which initially entangled with those of another field on observables like power spectrum are known in the context of the Schrödinger field theory. To clarify this effect in the Heisenberg picture, there were some attempts to construct the initial entangled state by making use of an entangled transformation (like Bogoliubov transformation) between the Bunch-Davies vacuums and squeezed states. We study the role of the time-dependent entangled transformation in the Schrödinger field theory. We derive the relation between two vacuum states which their mode functions are transformed by the entangled transformation in Schrödinger picture. We discuss that the time-dependency of the entanglement parameter is inevitable and only in the first order of the entanglement parameter perturbation this time-dependency vanishes. We study the entangled transformation in the Heisenberg picture in term of the entangled parameter which appears in the entangled state in Schrödinger picture.
Stapp`s quantum dualism: The James/Heisenberg model of consciousness
Energy Technology Data Exchange (ETDEWEB)
Noyes, H.P.
1994-02-18
Henry Stapp attempts to resolve the Cartesian dilemma by introducing what the author would characterize as an ontological dualism between mind and matter. His model for mind comes from William James` description of conscious events and for matter from Werner Heisenberg`s ontological model for quantum events (wave function collapse). His demonstration of the isomorphism between the two types of events is successful, but in the author`s opinion fails to establish a monistic, scientific theory. The author traces Stapp`s failure to his adamant rejection of arbitrariness, or `randomness`. This makes it impossible for him (or for Bohr and Pauli before him) to understand the power of Darwin`s explanation of biology, let along the triumphs of modern `neo-Darwinism`. The author notes that the point at issue is a modern version of the unresolved opposition between Leucippus and Democritus on one side and Epicurus on the other. Stapp`s views are contrasted with recent discussions of consciousness by two eminent biologists: Crick and Edelman. They locate the problem firmly in the context of natural selection on the surface of the earth. Their approaches provide a sound basis for further scientific work. The author briefly examines the connection between this scientific (rather than ontological) framework and the new fundamental theory based on bit-strings and the combinatorial hierarchy.
Search for the Heisenberg spin glass on rewired square lattices with antiferromagnetic interaction
International Nuclear Information System (INIS)
Surungan, Tasrief; Bansawang, B.J.; Tahir, Dahlang
2016-01-01
Spin glass (SG) is a typical magnetic system with frozen random spin orientation at low temperatures. The system exhibits rich physical properties, such as infinite number of ground states, memory effect, and aging phenomena. There are two main ingredients considered to be pivotal for the existence of SG behavior, namely, frustration and randomness. For the canonical SG system, frustration is led by the presence of competing interaction between ferromagnetic (FM) and antiferromagnetic (AF) couplings. Previously, Bartolozzi et al. [Phys. Rev. B73, 224419 (2006)], reported the SG properties of the AF Ising spins on scale free network (SFN). It is a new type of SG, different from the canonical one which requires the presence of both FM and AF couplings. In this new system, frustration is purely caused by the topological factor and its randomness is related to the irregular connectvity. Recently, Surungan et. al. [Journal of Physics: Conference Series, 640, 012001 (2015)] reported SG bahavior of AF Heisenberg model on SFN. We further investigate this type of system by studying an AF Heisenberg model on rewired square lattices. We used Replica Exchange algorithm of Monte Carlo Method and calculated the SG order parameter to search for the existence of SG phase.
Search for the Heisenberg spin glass on rewired cubic lattices with antiferromagnetic interaction
International Nuclear Information System (INIS)
Surungan, Tasrief
2016-01-01
Spin glass (SG) is a typical magnetic system which is mainly characterized by a frozen random spin orientation at low temperatures. Frustration and randomness are considered to be the key ingredients for the existence of SGs. Previously, Bartolozzi et al . [Phys. Rev. B73, 224419 (2006)] found that the antiferromagnetic (AF) Ising spins on scale free network (SFN) exhibited SG behavior. This is purely AF system, a new type of SG different from the canonical one which requires the presence of both FM and AF couplings. In this new system, frustration is purely due to a topological factor and its randomness is brought by irregular connectivity. Recently, it was reported that the AF Heisenberg model on SFN exhibited SG behavior [Surungan et al ., JPCS, 640, 012005 (2015)/doi:10.1088/1742-6596/640/1/012005]. In order to accommodate the notion of spatial dimension, we further investigated this type of system by studying an AF Heisenberg model on rewired cubic lattices, constructed by adding one extra bond randomly connecting each spin to one of its next-nearest neighbors. We used Replica Exchange algorithm of Monte Carlo Method and calculated the SG order parameter to search for the existence of SG phase. (paper)
Characterization of Phase Transition in Heisenberg Fluids from Density Functional Theory
International Nuclear Information System (INIS)
Li Liangsheng; Li Li; Chen Xiaosong
2009-01-01
The phase transition of Heisenberg fluid has been investigated with the density functional theory in mean-field approximation (MF). The matrix of the second derivatives of the grand canonical potential Ω with respect to the particle density fluctuations and the magnetization fluctuations has been investigated and diagonalized. The smallest eigenvalue being 0 signalizes the phase instability and the related eigenvector characterizes this phase transition. We find a Curie line where the order parameter is pure magnetization and a spinodal where the order parameter is a mixture of particle density and magnetization. Along the spinodal, the character of phase instability changes continuously from predominant condensation to predominant ferromagnetic phase transition with the decrease of total density. The spinodal meets the Curie line at the critical endpoint with the reduced density ρ* = ρσ 3 = 0.224 and the reduced temperature T* = kT/ element of = 1.87 (σ is the diameter of Heisenberg hard sphere and element of is the coupling constant).
DEFF Research Database (Denmark)
Albrechtslund, Anne-Mette Bech; Albrechtslund, Anders
of the series’ appeal is due to its epic chronicling of the flow of transgressing and intersecting knowledge environments in the story of Walter White’s gradual transformation from disheartened teacher to methamphetamine producing criminal mastermind. Walter uses his scientific training and knowledge...
1971-01-01
Remote from the noise and bustle of Europe's capital cities, in the charming German lake-side town of Lindau, close to the borders of Austria and Switzerland, Nobel Prize Winners in physics gathered together from June 28-July 2 to talk of their science and its interaction with society.
Magnetic ordering of quasi-1 D S=1/2 Heisenberg antiferromagnet Cu benzoate at sub-mK temperatures
International Nuclear Information System (INIS)
Karaki, Y.; Masutomi, R.; Kubota, M.; Ishimoto, H.; Asano, T.; Ajiro, Y.
2003-01-01
We have measured the AC susceptibility of quasi-1D S=1/2 Heisenberg antiferromagnet Cu benzoate at temperatures down to 0.2 mK. A sharp susceptibility peak is observed at 0.8 mK under an earth field. This fact indicates a 3D ordering of linear chains coupled by a weak magnetic interaction between chains
International Nuclear Information System (INIS)
Myrheim, J.
1993-06-01
The thesis deals with the application of different methods to the quantization problem for system of identical particles in one and two dimensions. The standard method is the analytic quantization method due to Schroedinger, which leads to the concept of fractional statistics in one and two dimensions. Two-dimensional particles with fractional statistics are well known by the name of anyons. Two alternative quantization methods are shown by the author, the algebraic method of Heisenberg and the Feynman path integral method. The Feynman method is closely related to the Schroedinger method, whereas the Heisenberg and Schroedinger methods may give different results. The relation between the Heisenberg and Schroedinger methods is discussed. The Heisenberg method is applied to the equations of motion of vortices in superfluid helium, which have the form of Hamiltonian equations for a one-dimensional system. The same method is also discussed more generally for systems of identical particles in one and two dimensions. An application of the Feynman method to the problem of computing the equation of state for a gas of anyons is presented. 104 refs., 4 figs
Penafiel, Carlos
2014-01-01
In this paper we find functions over bounded domains in the 2-dimensional Euclidean space, whose graphs (in the Heisenberg space) has constant mean curvature different from zero and taking on (possibly) infinite boundary values over the boundary of the domain.
arXiv Topology in the 2d Heisenberg Model under Gradient Flow
Sandoval, Ilya O.; de Forcrand, Philippe; Gerber, Urs; Mejía-Díaz, Héctor
2017-10-28
The 2d Heisenberg model — or 2d O(3) model — is popular in condensed matter physics, and in particle physics as a toy model for QCD. Along with other analogies, it shares with 4d Yang-Mills theories, and with QCD, the property that the configurations are divided in topological sectors. In the lattice regularisation the topological charge Q can still be defined such that $Q\\in \\mathbb{Z}$. It has generally been observed, however, that the topological susceptibility ${{\\chi }_{t}}=\\langle {{Q}^{2}}\\rangle /V$ does not scale properly in the continuum limit, i.e. that the quantity ${{\\chi }_{t}}{{\\xi }^{2}}$ diverges for ξ → ∞ (where ξ is the correlation length in lattice units). Here we address the question whether or not this divergence persists after the application of the Gradient Flow.
Adiabatically modeling quantum gates with two-site Heisenberg spins chain: Noise vs interferometry
Jipdi, M. N.; Tchoffo, M.; Fai, L. C.
2018-02-01
We study the Landau Zener (LZ) dynamics of a two-site Heisenberg spin chain assisted with noise and focus on the implementation of logic gates via the resulting quantum interference. We present the evidence of the quantum interference phenomenon in triplet spin states and confirm that, three-level systems mimic Landau-Zener-Stückelberg (LZS) interferometers with occupancies dependent on the effective phase. It emerges that, the critical parameters tailoring the system are obtained for constructive interferences where the two sets of the chain are found to be maximally entangled. Our findings demonstrate that the enhancement of the magnetic field strength suppresses noise effects; consequently, the noise severely impacts the occurrence of quantum interference for weak magnetic fields while for strong fields, quantum interference subsists and allows the modeling of universal sets of quantum gates.
Signatures of Dirac Cones in a DMRG Study of the Kagome Heisenberg Model
Directory of Open Access Journals (Sweden)
Yin-Chen He
2017-07-01
Full Text Available The antiferromagnetic spin-1/2 Heisenberg model on a kagome lattice is one of the most paradigmatic models in the context of spin liquids, yet the precise nature of its ground state is not understood. We use large-scale density matrix renormalization group simulations (DMRG on infinitely long cylinders and find indications for the formation of a gapless Dirac spin liquid. First, we use adiabatic flux insertion to demonstrate that the spin gap is much smaller than estimated from previous DMRG simulation. Second, we find that the momentum-dependent excitation spectrum, as extracted from the DMRG transfer matrix, exhibits Dirac cones that match those of a π-flux free-fermion model [the parton mean-field ansatz of a U(1 Dirac spin liquid].
International Nuclear Information System (INIS)
Mishra, Utkarsh; Rakshit, Debraj; Prabhu, R; Sen, Aditi; Sen, Ujjwal
2016-01-01
Disordered systems form one of the centrestages of research in many body sciences and lead to a plethora of interesting phenomena and applications. A paradigmatic disordered system consists of a one-dimensional array of quantum spin-1/2 particles, governed by the Heisenberg spin glass Hamiltonian with natural or engineered quenched disordered couplings in an external magnetic field. These systems allow disorder-induced enhancement for bipartite and multipartite observables. Here we show that simultaneous application of independent quenched disorders results in disorder-induced enhancement, while the same is absent with individual application of the same disorders. We term the phenomenon as constructive interference and the corresponding parameter stretches as the Venus regions. Interestingly, it has only been observed for multiparty entanglement and is absent for the single- and two-party physical quantities. (paper)
The Hypermultiplet with Heisenberg Isometry in N=2 Global and Local Supersymmetry
Ambrosetti, Nicola; Derendinger, Jean-Pierre; Tziveloglou, Panteleimon
2011-01-01
The string coupling of N=2 supersymmetric compactifications of type II string theory on a Calabi-Yau manifold belongs to the so-called universal dilaton hypermultiplet, that has four real scalars living on a quaternion-Kaehler manifold. Requiring Heisenberg symmetry, which is a maximal subgroup of perturbative isometries, reduces the possible manifolds to a one-parameter family that describes the tree-level effective action deformed by the only possible perturbative correction arising at one-loop level. A similar argument can be made at the level of global supersymmetry where the scalar manifold is hyper-Kaehler. In this work, the connection between global and local supersymmetry is explicitly constructed, providing a non-trivial gravity decoupled limit of type II strings already in perturbation theory.
Classical ground states of Heisenberg and X Y antiferromagnets on the windmill lattice
Jeevanesan, Bhilahari; Orth, Peter P.
2014-10-01
We investigate the classical Heisenberg and planar (X Y ) spin models on the windmill lattice. The windmill lattice is formed out of two widely occurring lattice geometries: a triangular lattice is coupled to its dual honeycomb lattice. Using a combination of iterative minimization, heat-bath Monte Carlo simulations, and analytical calculations, we determine the complete ground-state phase diagram of both models and find the exact energies of the phases. The phase diagram shows a rich phenomenology due to competing interactions and hosts, in addition to collinear and various coplanar phases, also intricate noncoplanar phases. We briefly outline different paths to an experimental realization of these spin models. Our extensive study provides a starting point for the investigation of quantum and thermal fluctuation effects.
Emergent criticality and Friedan scaling in a two-dimensional frustrated Heisenberg antiferromagnet
Orth, Peter P.; Chandra, Premala; Coleman, Piers; Schmalian, Jörg
2014-03-01
We study a two-dimensional frustrated Heisenberg antiferromagnet on the windmill lattice consisting of triangular and dual honeycomb lattice sites. In the classical ground state, the spins on different sublattices are decoupled, but quantum and thermal fluctuations drive the system into a coplanar state via an "order from disorder" mechanism. We obtain the finite temperature phase diagram using renormalization group approaches. In the coplanar regime, the relative U(1) phase between the spins on the two sublattices decouples from the remaining degrees of freedom, and is described by a six-state clock model with an emergent critical phase. At lower temperatures, the system enters a Z6 broken phase with long-range phase correlations. We derive these results by two distinct renormalization group approaches to two-dimensional magnetism: Wilson-Polyakov scaling and Friedan's geometric approach to nonlinear sigma models where the scaling of the spin stiffnesses is governed by the Ricci flow of a 4D metric tensor.
Abhinav, Kumar; Guha, Partha
2018-03-01
Through the Hasimoto map, various dynamical systems can be mapped to different integrodifferential generalizations of Nonlinear Schrödinger (NLS) family of equations some of which are known to be integrable. Two such continuum limits, corresponding to the inhomogeneous XXX Heisenberg spin chain [J. Phys. C 15, L1305 (1982)] and that of a thin vortex filament moving in a superfluid with drag [Eur. Phys. J. B 86, 275 (2013) 86; Phys. Rev. E 91, 053201 (2015)], are shown to be particular non-holonomic deformations (NHDs) of the standard NLS system involving generalized parameterizations. Crucially, such NHDs of the NLS system are restricted to specific spectral orders that exactly complements NHDs of the original physical systems. The specific non-holonomic constraints associated with these integrodifferential generalizations additionally posses distinct semi-classical signature.
Factors on the magnetic properties of the iron nanoparticles by classical Heisenberg model
Nguyen, Trong Dung; Nguyen, Chinh Cuong; Nguyen, The Toan; Pham, Khac Hung
2018-03-01
In this paper, we used the Monte-Carlo simulation technique to investigate the magnetic properties of the samples of amorphous iron material which could be described as a spin Heisenberg system. The exchange interaction is taken into account as a function of the distance between the two spins. The results showed the existence of the magnetic phase transition behavior of the nanoparticles. The phase transition temperature obtained by our simulations and the semi-empirical calculations are well matched. The magnetization of the core/shell system strongly depends on the shell thickness when the spins on the interface of the core and the shell layer are frustrated. The transition temperature seems to be independent on the structure of the shell.
Degenerate and chiral states in the extended Heisenberg model on the kagome lattice
Gómez Albarracín, F. A.; Pujol, P.
2018-03-01
We present a study of the low-temperature phases of the antiferromagnetic extended classical Heisenberg model on the kagome lattice, up to third-nearest neighbors. First, we focus on the degenerate lines in the boundaries of the well-known staggered chiral phases. These boundaries have either semiextensive or extensive degeneracy, and we discuss the partial selection of states by thermal fluctuations. Then, we study the model under an external magnetic field on these lines and in the staggered chiral phases. We pay particular attention to the highly frustrated point, where the three exchange couplings are equal. We show that this point can be mapped to a model with spin-liquid behavior and nonzero chirality. Finally, we explore the effect of Dzyaloshinskii-Moriya (DM) interactions in two ways: a homogeneous and a staggered DM interaction. In both cases, there is a rich low-temperature phase diagram, with different spontaneously broken symmetries and nontrivial chiral phases.
Nonequilibrium behaviors of the three-dimensional Heisenberg model in the Swendsen-Wang algorithm
Nonomura, Yoshihiko; Tomita, Yusuke
2016-01-01
Recently, it was shown [Y. Nonomura, J. Phys. Soc. Jpn. 83, 113001 (2014), 10.7566/JPSJ.83.113001] that the nonequilibrium critical relaxation of the two-dimensional (2D) Ising model from a perfectly ordered state in the Wolff algorithm is described by stretched-exponential decay, and a universal scaling scheme was found to connect nonequilibrium and equilibrium behaviors. In the present study we extend these findings to vector spin models, and the 3D Heisenberg model could be a typical example. To evaluate the critical temperature and critical exponents precisely using the above scaling scheme, we calculate nonequilibrium ordering from the perfectly disordered state in the Swendsen-Wang algorithm, and we find that the critical ordering process is described by stretched-exponential growth with a comparable exponent to that of the 3D X Y model. The critical exponents evaluated in the present study are consistent with those in previous studies.
Johnson; Thywissen; Dekker; Berggren; Chu; Younkin; Prentiss
1998-06-05
The spatially dependent de-excitation of a beam of metastable argon atoms, traveling through an optical standing wave, produced a periodic array of localized metastable atoms with position and momentum spreads approaching the limit stated by the Heisenberg uncertainty principle. Silicon and silicon dioxide substrates placed in the path of the atom beam were patterned by the metastable atoms. The de-excitation of metastable atoms upon collision with the surface promoted the deposition of a carbonaceous film from a vapor-phase hydrocarbon precursor. The resulting patterns were imaged both directly and after chemical etching. Thus, quantum-mechanical steady-state atom distributions can be used for sub-0.1-micrometer lithography.
Energy Technology Data Exchange (ETDEWEB)
Pozo, J.; Leon, A. [Instituto de Ciencias Basicas, Facultad de Ingenieria, Universidad Diego Portales, Casilla 298-V, Santiago (Chile)]. e-mail: julio.pozo@udp.cl
2006-07-01
In this paper we investigate the presence of out-of-plane spin deviation {rho}({xi}) in the easy-plane ferromagnetic Heisenberg chain by using the coupled-boson operators together with the Schwinger transformation for the spin operator; this method allows us to conclude that the critical behaviour of the instability is due to the velocity of the nonlinear excitations (solitons) only for an appropriate range of the magnetic field. In this case, when the velocity becomes lower, the stable soliton corresponding to {rho}({xi}) is distorted by magnons and loses stability. If we increase the velocity of {rho}({xi}), it then decays into high frequency-oscillations. Nevertheless, we find an opposite competence effect produced by the velocity and the magnetic field on {rho}({xi}). (Author)
Neutron Scattering from the Heisenberg Ferromagnets EuO and EuS
DEFF Research Database (Denmark)
Dietrich, O. W.; Als-Nielsen, Jens Aage; Passell, L.
1976-01-01
Inelastic neutron scattering has been used to investigate the spin dynamics of the isotropic Heisenberg ferromagnet EuO over a wide range of wave vectors and over a temperature range extending from 0.14 to 1.9TC. Below the ordering temperature spin-wave renormalization is found to agree well...... with the predictions of Dyson-Maleev theory (including the dynamical but not the kinematical interaction) when both exchange and dipolar couplings between the Eu2+ ions are taken into account. At temperatures near TC broadening of the spin-wave lines was observed. For hydrodynamic spin waves, the wave......-vector dependence of the linewidths is found to be consistent with the expectations of microscopic spin-wave theory and the temperature dependence with predictions based on dynamical scaling. At TC, linewidths were found to deviate from the q5/2 wave-vector dependence expected on the basis of dynamical scaling...
Towards exact solutions of the non-linear Heisenberg-Pauli-Weyl spinor equation
International Nuclear Information System (INIS)
Mielke, E.W.
1980-03-01
In ''color geometrodynamics'' fundamental spinor fields are assumed to obey a GL(2f,C) x GL(2c,C) gauge-invariant nonlinear spinor equation of the Heisenberg-Pauli-Weyl type. Quark confinement, assimilating a scheme of Salam and Strathdee, is (partially) mediated by the tensor ''gluons'' of strong gravity. This hypothesis is incorporated into the model by considering the nonlinear Dirac equation in a curved space-time of hadronic dimensions. Disregarding internal degrees of freedom, it is then feasible, for a particular background space-time, to obtain exact solutions of the spherical bound-state problem. Finally, these solutions are tentatively interpreted as droplet-type solitons and remarks on their interrelation with Wheeler's geon construction are made. (author)
The semi-infinite anisotropic spin-1/2 Heisenberg ferromagnet
International Nuclear Information System (INIS)
Benyoussef, A.; Boubekri, A.; Ez-Zahraouy, H.; Saber, M.
1998-08-01
Using the effective field theory with a probability distribution technique that accounts for the self-spin correlation functions, the phase transitions in the semi-infinite anisotropic spin-1/2 Heisenberg ferromagnet on a simple cubic lattice are examined. For fixed values of the reduced exchange anisotropic parameter, the critical temperature of the system is studied as a function of the ratio R of the surface exchange couplings to the bulk ones. It was found that if R ≤ R c , the system orders at the bulk critical temperature T B c /J and if R ≥ R c , the system exhibits two successive transitions. The surface orders at the surface critical temperature T S c /J which is higher than T B c /J and as the temperature is lowered, in the presence of ordered surface, the bulk orders at T B c /J. (author)
Krivoruchko, V. N.
2017-11-01
In spite of the fact that dynamical properties of magnets have been extensively studied over the past years, the longitudinal magnetization dynamics is still much less understood than transverse one even in the equilibrium state of a system. In this paper, we give a review of existing, based on quantum-mechanical approach, theoretical descriptions of the longitudinal magnetization dynamics for ferro-, ferri- and antiferromagnetic dielectrics. The aim is to reveal specific features of this type of magnetization vibrations under description a system within the framework of one of the basic model theory of magnetism—the Heisenberg model. Related experimental investigations as well as open questions are also briefly discussed. We hope that understanding of the longitudinal magnetization dynamics distinctive features in the equilibrium state have to be a reference point for a theory uncovering the physical mechanisms that govern ultrafast spin dynamics after femtosecond laser pulse demagnetization when a system is far beyond an equilibrium state.
Directory of Open Access Journals (Sweden)
Mihai V. Putz
2010-10-01
Full Text Available Within the path integral Feynman formulation of quantum mechanics, the fundamental Heisenberg Uncertainty Relationship (HUR is analyzed in terms of the quantum fluctuation influence on coordinate and momentum estimations. While introducing specific particle and wave representations, as well as their ratio, in quantifying the wave-to-particle quantum information, the basic HUR is recovered in a close analytical manner for a large range of observable particle-wave Copenhagen duality, although with the dominant wave manifestation, while registering its progressive modification with the factor √1-n2, in terms of magnitude n ε [0,1] of the quantum fluctuation, for the free quantum evolution around the exact wave-particle equivalence. The practical implications of the present particle-to-wave ratio as well as of the free-evolution quantum picture are discussed for experimental implementation, broken symmetry and the electronic localization function.
The phase transition in the anisotropic Heisenberg model with long range dipolar interactions
International Nuclear Information System (INIS)
Mól, L.A.S.; Costa, B.V.
2014-01-01
In this work we have used extensive Monte Carlo calculations to study the planar to paramagnetic phase transition in the two-dimensional anisotropic Heisenberg model with dipolar interactions (AHd) considering the true long-range character of the dipolar interactions by means of the Ewald summation. Our results are consistent with an order–disorder phase transition with unusual critical exponents in agreement with our previous results for the Planar Rotator model with dipolar interactions. Nevertheless, our results disagree with the Renormalization Group results of Maier and Schwabl [Phys. Rev. B, 70, 134430 (2004)] [13] and the results of Rapini et al. [Phys. Rev. B, 75, 014425 (2007)] [12], where the AHd was studied using a cut-off in the evaluation of the dipolar interactions. We argue that besides the long-range character of dipolar interactions their anisotropic character may have a deeper effect in the system than previously believed. Besides, our results show that the use of a cut-off radius in the evaluation of dipolar interactions must be avoided when analyzing the critical behavior of magnetic systems, since it may lead to erroneous results. - Highlights: • The anisotropic Heisenberg model with dipolar interactions is studied. • True long-range interactions were considered by means of Ewald summation. • We found an order–disorder phase transition with unusual critical exponents. • Previous results show a different behavior when a cut-off radius is introduced. • The use of a cut-off radius must be avoided when dealing with dipolar systems
Emergent quantum phases in a frustrated J1-J2 Heisenberg model on the hyperhoneycomb lattice
Lee, SungBin; Jeong, Jae-Seung; Hwang, Kyusung; Kim, Yong Baek
2014-10-01
We investigate possible quantum ground states as well as the classical limit of a frustrated J1-J2 Heisenberg model on the three-dimensional (3D) hyperhoneycomb lattice. Our study is inspired by the recent discovery of β -Li2IrO3 , where Ir4 + ions form a 3D network with each lattice site being connected to three nearest neighbors. We focus on the influence of magnetic frustration caused by the second-nearest-neighbor spin interactions. Such interactions are likely to be significant due to the large extent of 5 d orbitals in iridates or other 5 d transition metal oxides. In the classical limit, the ground state manifold is given by line degeneracies of the spiral magnetic-order wave vectors when J2/J1≳0.17 while the collinear stripy order is included in the degenerate manifold when J2/J1=0.5 . Quantum order-by-disorder effects are studied using both the semiclassical 1 /S expansion in the spin-wave theory and the Schwinger-boson approach. In general, certain coplanar spiral orders are chosen from the classical degenerate manifold for a large fraction of the phase diagram. Nonetheless quantum fluctuations favor the collinear stripy order over the spiral orders in an extended parameter region around J2/J1=0.5 , despite the spin-rotation invariance of the underlying Hamiltonian. This is in contrast to the emergence of stripy order in the Heisenberg-Kitaev model studied earlier on the same lattice, where the Kitaev-type Ising interactions are important for stabilizing the stripy order. As quantum fluctuations become stronger, U (1 ) and Z2 quantum spin liquid phases are shown to arise via quantum disordering of the Néel, stripy, and spiral magnetically ordered phases. The effects of magnetic anisotropy and their relevance to future experiments are also discussed.
EuCo2P2 : A model molecular-field helical Heisenberg antiferromagnet
Sangeetha, N. S.; Cuervo-Reyes, Eduardo; Pandey, Abhishek; Johnston, D. C.
2016-07-01
The metallic compound EuCo2P2 with the body-centered tetragonal ThCr2Si2 structure containing Eu spins-7/2 was previously shown from single-crystal neutron diffraction measurements to exhibit a helical antiferromagnetic (AFM) structure below TN=66.5 K with the helix axis along the c axis and with the ordered moments aligned within the a b plane. Here we report crystallography, electrical resistivity, heat capacity, magnetization, and magnetic susceptibility measurements on single crystals of this compound. We demonstrate that EuCo2P2 is a model molecular-field helical Heisenberg antiferromagnet from comparisons of the anisotropic magnetic susceptibility χ , high-field magnetization, and magnetic heat capacity of EuCo2P2 single crystals at temperature T ≤TN with the predictions of our recent formulation of molecular-field theory. Values of the Heisenberg exchange interactions between the Eu spins are derived from the data. The low-T magnetic heat capacity ˜T3 arising from spin-wave excitations with no anisotropy gap is calculated and found to be comparable to the lattice heat capacity. The density of states at the Fermi energy of EuCo2P2 and the related compound BaCo2P2 are found from the heat capacity data to be large, 10 and 16 states/eV per formula unit for EuCo2P2 and BaCo2P2 , respectively. These values are enhanced by a factor of ˜2.5 above those found from DFT electronic structure calculations for the two compounds. The calculations also find ferromagnetic Eu-Eu exchange interactions within the a b plane and AFM interactions between Eu spins in nearest- and next-nearest planes, in agreement with the MFT analysis of χa b(T ≤TN) .
Global entanglement and quantum phase transitions in the transverse XY Heisenberg chain
Radgohar, Roya; Montakhab, Afshin
2018-01-01
We provide a study of various quantum phase transitions occurring in the XY Heisenberg chain in a transverse magnetic field using the Meyer-Wallach (MW) measure of (global) entanglement. Such a measure, while being readily evaluated, is a multipartite measure of entanglement as opposed to more commonly used bipartite measures. Consequently, we obtain analytic expression of the measure for finite-size systems and show that it can be used to obtain critical exponents via finite-size scaling with great accuracy for the Ising universality class. We also calculate an analytic expression for the isotropic (XX) model and show that global entanglement can precisely identify the level-crossing points. The critical exponent for the isotropic transition is obtained exactly from an analytic expression for global entanglement in the thermodynamic limit. Next, the general behavior of the measure is calculated in the thermodynamic limit considering the important role of symmetries for this limit. The so-called oscillatory transition in the ferromagnetic regime can only be characterized by the thermodynamic limit where global entanglement is shown to be zero on the transition curve. Finally, the anisotropic transition is explored where it is shown that global entanglement exhibits an interesting behavior in the finite-size limit. In the thermodynamic limit, we show that global entanglement shows a cusp singularity across the Ising and anisotropic transition, while showing non-analytic behavior at the XX multicritical point. It is concluded that global entanglement, despite its relative simplicity, can be used to identify all the rich structure of the ground-state Heisenberg chain.
Energy Technology Data Exchange (ETDEWEB)
Parente, Walter E.F.; Pacobahyba, J.T.M.; Araújo, Ijanílio G. [Departamento de Física, Universidade Federal de Roraima, BR 174, Km 12. Bairro Monte Cristo. CEP: 69300-000 Boa Vista, Roraima (Brazil); Neto, Minos A., E-mail: minos@pq.cnpq.br [Universidade Federal do Amazonas, Departamento de Física, 3000, Japiim, 69077-000, Manaus-AM (Brazil); Ricardo de Sousa, J. [Universidade Federal do Amazonas, Departamento de Física, 3000, Japiim, 69077-000, Manaus-AM (Brazil); National Institute of Science and Technology for Complex Systems, 3000, Japiim, 69077-000, Manaus-AM (Brazil); Akinci, Ümit [Department of Physics, Dokuz Eylül University, Tr-35160 Izmir (Turkey)
2014-04-15
In this paper we study the quantum spin-1/2 anisotropic Heisenberg antiferromagnet model in the presence of a Dzyaloshinskii–Moriya interaction (D) and a uniform longitudinal (H) magnetic field. Using the effective-field theory with a finite cluster N=2 spin (EFT-2) we calculate the phase diagrams in the H−T and D−T planes on a simple cubic lattice (z=6). We have only observed second order phase transitions for values between Δ∈[0,1], where the cases were analysed: Ising (Δ=1), anisotropic Heisenberg (Δ=0.6) and isotropic Heisenberg (Δ=0). - Highlights: • Anisotropic Heisenberg antiferromagnet on a simple cubic lattice. • Effective-field theory. • Dzyaloshinskii–Moriya interaction.
Inégalités de Poincaré et de Sobolev pour les formes différentielles sur les groupes de Heisenberg
Baldi, Annalisa; Franchi, Bruno; Pansu, Pierre
2017-01-01
Poincaré and Sobolev inequalities for differential forms on Heisenberg balls, involving Rumin's differentials, are given. Furthermore, a global homotopy of Rumin's complex which improves differentiability of Rumin forms is provided on any bounded geometry contact manifold.
International Nuclear Information System (INIS)
Masiello, Emiliano; Martin, Brunella; Do, Jean-Michel
2011-01-01
A new development for the IDT solver is presented for large reactor core applications in XYZ geometries. The multigroup discrete-ordinate neutron transport equation is solved using a Domain-Decomposition (DD) method coupled with the Coarse-Mesh Finite Differences (CMFD). The later is used for accelerating the DD convergence rate. In particular, the external power iterations are preconditioned for stabilizing the oscillatory behavior of the DD iterative process. A set of critical 2-D and 3-D numerical tests on a single processor will be presented for the analysis of the performances of the method. The results show that the application of the CMFD to the DD can be a good candidate for large 3D full-core parallel applications. (author)
Alcance y Función de las Teorias Físicas em Hylary Putnam y Werner Heisenberg
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Christian de Ronde
2013-08-01
Full Text Available In this work we attempt to analyze the intra-theoretic characterization provided by Hilary Putnam and Werner Heisenberg between quantum mechanics and other theories. The first defended the idea that physical theories include macro principles that under specific definite historical conditions can be revised on the light of rival principles. Putnam will concentrate in the impact that quantum mechanics has produced in the classical image of knowledge. Heisenberg, on the other hand, develops his analysis from the notion of closed theories, assuming the independence and incommensurability of physical theories. These divergences between the two authors will allow us to analyze how the disagreement in the consideration of the status of physical theories, goes deeper into more profound aspects related to the nature of knowledge and the relation between theory and world
Alécio, Raphael Cavalcante; Strečka, Jozef; Lyra, Marcelo L.
2018-04-01
The thermodynamic behavior of an Ising-Heisenberg triangular tube with Heisenberg intra-rung and Ising inter-rung interactions is exactly obtained in an external magnetic field within the framework of the transfer-matrix method. We report rigorous results for the temperature dependence of the magnetization, entropy, pair correlations and specific heat, as well as typical iso-entropic curves. The discontinuous field-driven ground-state phase transitions are reflected in some anomalous thermodynamic behavior as for instance a striking low-temperature peak of the specific heat and an enhanced magnetocaloric effect. It is demonstrated that the intermediate magnetization plateaus shrink in and the relevant sharp edges associated with the magnetization jump round off upon increasing temperature.
Magnetization plateaus in the spin-1/2 antiferromagnetic Heisenberg model on a kagome-strip chain
Morita, Katsuhiro; Sugimoto, Takanori; Sota, Shigetoshi; Tohyama, Takami
2018-01-01
The spin-1/2 Heisenberg model on a kagome lattice is a typical frustrated quantum spin system. The basic structure of a kagome lattice is also present in the kagome-strip lattice in one dimension, where a similar type of frustration is expected. We thus study the magnetization plateaus of the spin-1/2 Heisenberg model on a kagome-strip chain with three-independent antiferromagnetic exchange interactions using the density-matrix renormalization-group method. In a certain range of exchange parameters, we find twelve kinds of magnetization plateaus, nine of which have magnetic structures breaking translational and/or reflection symmetry spontaneously. The structures are classified by an array of five-site unit cells with specific bond-spin correlations. In a case with a nontrivial plateau, namely a 3/10 plateau, we find long-period magnetic structure with a period of four unit cells.
Manojlović, N.; Salom, I.
2017-10-01
The implementation of the algebraic Bethe ansatz for the XXZ Heisenberg spin chain in the case, when both reflection matrices have the upper-triangular form is analyzed. The general form of the Bethe vectors is studied. In the particular form, Bethe vectors admit the recurrent procedure, with an appropriate modification, used previously in the case of the XXX Heisenberg chain. As expected, these Bethe vectors yield the strikingly simple expression for the off-shell action of the transfer matrix of the chain as well as the spectrum of the transfer matrix and the corresponding Bethe equations. As in the XXX case, the so-called quasi-classical limit gives the off-shell action of the generating function of the corresponding trigonometric Gaudin Hamiltonians with boundary terms.
Ceria, Paul; Ducourtieux, Sebastien; Boukellal, Younes; Allard, Alexandre; Fischer, Nicolas; Feltin, Nicolas
2017-03-01
In order to evaluate the uncertainty budget of the LNE’s mAFM, a reference instrument dedicated to the calibration of nanoscale dimensional standards, a numerical model has been developed to evaluate the measurement uncertainty of the metrology loop involved in the XYZ positioning of the tip relative to the sample. The objective of this model is to overcome difficulties experienced when trying to evaluate some uncertainty components which cannot be experimentally determined and more specifically, the one linked to the geometry of the metrology loop. The model is based on object-oriented programming and developed under Matlab. It integrates one hundred parameters that allow the control of the geometry of the metrology loop without using analytical formulae. The created objects, mainly the reference and the mobile prism and their mirrors, the interferometers and their laser beams, can be moved and deformed freely to take into account several error sources. The Monte Carlo method is then used to determine the positioning uncertainty of the instrument by randomly drawing the parameters according to their associated tolerances and their probability density functions (PDFs). The whole process follows Supplement 2 to ‘The Guide to the Expression of the Uncertainty in Measurement’ (GUM). Some advanced statistical tools like Morris design and Sobol indices are also used to provide a sensitivity analysis by identifying the most influential parameters and quantifying their contribution to the XYZ positioning uncertainty. The approach validated in the paper shows that the actual positioning uncertainty is about 6 nm. As the final objective is to reach 1 nm, we engage in a discussion to estimate the most effective way to reduce the uncertainty.
Tribedi, Amit; Bose, Indrani
2008-01-01
We consider a two-chain, spin-1/2 antiferromagnetic Heisenberg spin ladder in an external magnetic field H. The spin ladder is known to undergo second order quantum phase transitions (QPTs) at two critical values, Hc1 and Hc2, of the magnetic field. There are now known examples of strongly coupled (rung exchange interaction much stronger than nearest-neighbour intrachain exchange interaction) organic ladder compounds in which QPTs have been experimentally observed. In this paper, we investiga...
Comment on ‘Adjacent spin operator dynamical structure factor of the S = 1/2 Heisenberg chain’
International Nuclear Information System (INIS)
De Gier, Jan
2012-01-01
We consider the paper ‘Adjacent spin operator dynamical structure factor of the S = 1/2 Heisenberg chain’, by Klauser, Mossel and Caux (2012 J. Stat. Mech. P03012) to be a new and important step in the numerical analysis of the correlation functions of quantum spin chains. The correlation functions considered in this paper were not previously computed, their analytical study is extremely complicated and the numerical results can be used for comparison with experiments. (news and perspectives)
Exact solution of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chain
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L. Čanová
2009-01-01
Full Text Available The geometric frustration in a class of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chains is investigated by combining three exact analytical techniques: Kambe projection method, decoration-iteration transformation and transfer-matrix method. The ground state, the magnetization process and the specific heat as a function of the external magnetic field are particularly examined for different strengths of the geometric frustration. It is shown that the increase of the Heisenberg spin value S raises the number of intermediate magnetization plateaux, which emerge in magnetization curves provided that the ground state is highly degenerate on behalf of a sufficiently strong geometric frustration. On the other hand, all intermediate magnetization plateaux merge into a linear magnetization versus magnetic field dependence in the limit of classical Heisenberg spin S → ∞. The enhanced magnetocaloric effect with cooling rate exceeding the one of paramagnetic salts is also detected when the disordered frustrated phase constitutes the ground state and the external magnetic field is small enough.
Investigation of the chiral antiferromagnetic Heisenberg model using projected entangled pair states
Poilblanc, Didier
2017-09-01
A simple spin-1/2 frustrated antiferromagnetic Heisenberg model (AFHM) on the square lattice—including chiral plaquette cyclic terms—was argued [A. E. B. Nielsen, G. Sierra, and J. I. Cirac, Nat. Commun. 4, 2864 (2013), 10.1038/ncomms3864] to host a bosonic Kalmeyer-Laughlin (KL) fractional quantum Hall ground state [V. Kalmeyer and R. B. Laughlin, Phys. Rev. Lett. 59, 2095 (1987), 10.1103/PhysRevLett.59.2095]. Here, we construct generic families of chiral projected entangled pair states (chiral PEPS) with low bond dimension (D =3 ,4 ,5 ) which, upon optimization, provide better variational energies than the KL Ansatz. The optimal D =3 PEPS exhibits chiral edge modes described by the Wess-Zumino-Witten SU(2) 1 model, as expected for the KL spin liquid. However, we find evidence that, in contrast to the KL state, the PEPS spin liquids have power-law dimer-dimer correlations and exhibit a gossamer long-range tail in the spin-spin correlations. We conjecture that these features are genuine to local chiral AFHM on bipartite lattices.
Properties of magnetic impurities embedded into an anisotropic Heisenberg chain with spin gap
International Nuclear Information System (INIS)
Schlottmann, P.
2000-01-01
We consider a U(1)-invariant model consisting of the integrable anisotropic easy-axis Heisenberg chain of arbitrary spin S embedding an impurity of spin S'. The host chain has a spin gap for all values of S. The ground state properties and the elementary excitations of the host are studied as a function of the anisotropy and the magnetic field. The impurity is located on a link of the chain and interacts only with both neighboring sites. The coupling of the impurity to the lattice can be tuned by the impurity rapidity p 0 (usually playing the role of the Kondo coupling). The impurity model is then integrable as a function of two continuous parameters (the anisotropy and the impurity rapidity) and two discrete variables (the spins S and S'). The Bethe ansatz equations are derived and used to obtain the magnetization of the impurity. The impurity magnetization is non-universal as a function of p 0 . For small fields the impurity magnetization is determined by the spin gap and the van Hove singularity of the rapidity band. For an overcompensated impurity (S'< S) at intermediate fields there is a crossover to non-Fermi-liquid behavior remnant from the suppressed quantum critical point
Weakly coupled S=1/2 quantum Heisenberg antiferromagnetic chains in an effective staggered field
International Nuclear Information System (INIS)
Sato, Masahiro; Oshikawa, Masaki
2002-01-01
We study weakly coupled S=1/2 quantum Heisenberg antiferromagnetic chains in an effective staggered field. Applying mean-field (MF) theory, spin-wave theory and chain MF (CMF) theory, we can see analytically some effects of the staggered field in this higher dimensional spin system. In particular, when the staggered field and the inter-chain inter-action compete with each other, we conjecture from the MF theory that a nontrivial phase is present. The spin wave theory predicts that the behavior of the gaps induced by a staggered field is different between the competitive case and the non-competitive case. When the inter-chain interactions are weak enough, we can improve the MF phase diagram by using CMF theory and the analytical results of field theories. The ordered phase region predicted by the CMF theory is fairly smaller than one of the MF theory. Cu-benzoate, CuCl 2 · 2DMSO (dimethylsulphoxide), BaCu 2 (Si 1-x Ge x ) 2 O 7 , etc., could be described by our model in enough low temperature. (author)
S =1/2 ferromagnetic-antiferromagnetic alternating Heisenberg chain in a zinc-verdazyl complex
Yamaguchi, Hironori; Shinpuku, Yasuhiro; Shimokawa, Tokuro; Iwase, Kenji; Ono, Toshio; Kono, Yohei; Kittaka, Shunichiro; Sakakibara, Toshiro; Hosokoshi, Yuko
2015-02-01
We successfully synthesized the zinc-verdazyl complex [Zn(hfac)2].(o -Py -V ) [hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate; o -Py-V = 3-(2-pyridyl)-1,5-diphenylverdazyl], which is an ideal model compound with an S = 1/2 ferromagnetic-antiferromagnetic alternating Heisenberg chain (F-AF AHC). Ab initio molecular-orbital (MO) calculations indicate that two dominant interactions JF and JAF form the S = 1/2 F-AF AHC in this compound. The magnetic susceptibility and magnetic specific heat of the compound exhibit thermally activated behavior below approximately 1 K. Furthermore, its magnetization curve is observed up to the saturation field and directly indicates a zero-field excitation gap of 0.5 T. These experimental results provide evidence for the existence of a Haldane gap. We successfully explain the results in terms of the S = 1/2 F-AF AHC through quantum Monte Carlo calculations with | JAF/JF|=0.22 . The ab initio MO calculations also indicate a weak AF interchain interaction J' and that the coupled F-AF AHCs form a honeycomb lattice. The J' dependence of the Haldane gap is calculated, and the actual value of J' is determined to be less than 0.01 | JF| .
One dimensionalization in the spin-1 Heisenberg model on the anisotropic triangular lattice
Gonzalez, M. G.; Ghioldi, E. A.; Gazza, C. J.; Manuel, L. O.; Trumper, A. E.
2017-11-01
We investigate the effect of dimensional crossover in the ground state of the antiferromagnetic spin-1 Heisenberg model on the anisotropic triangular lattice that interpolates between the regime of weakly coupled Haldane chains (J'≪J ) and the isotropic triangular lattice (J'=J ). We use the density-matrix renormalization group (DMRG) and Schwinger boson theory performed at the Gaussian correction level above the saddle-point solution. Our DMRG results show an abrupt transition between decoupled spin chains and the spirally ordered regime at (J'/J) c˜0.42 , signaled by the sudden closing of the spin gap. Coming from the magnetically ordered side, the computation of the spin stiffness within Schwinger boson theory predicts the instability of the spiral magnetic order toward a magnetically disordered phase with one-dimensional features at (J'/J) c˜0.43 . The agreement of these complementary methods, along with the strong difference found between the intra- and the interchain DMRG short spin-spin correlations for sufficiently large values of the interchain coupling, suggests that the interplay between the quantum fluctuations and the dimensional crossover effects gives rise to the one-dimensionalization phenomenon in this frustrated spin-1 Hamiltonian.
The spin-partitioned total position-spread tensor: An application to Heisenberg spin chains
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Fertitta, Edoardo; Paulus, Beate [Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany); El Khatib, Muammar; Evangelisti, Stefano; Leininger, Thierry [Laboratoire de Chimie et Physique Quantiques–LCPQ/IRSAMC, Université de Toulouse (UPS) et CNRS (UMR-5626), 118 Route de Narbonne, Toulouse Cedex 31062 (France); Bendazzoli, Gian Luigi [Dipartimento di Chimica Industriale “Toso Montanari,” Università di Bologna, Viale Risorgimento 4, I–40136 Bologna (Italy)
2015-12-28
The spin partition of the Total Position-Spread (TPS) tensor has been performed for one-dimensional Heisenberg chains with open boundary conditions. Both the cases of a ferromagnetic (high-spin) and an anti-ferromagnetic (low-spin) ground-state have been considered. In the case of a low-spin ground-state, the use of alternating magnetic couplings allowed to investigate the effect of spin-pairing. The behavior of the spin-partitioned TPS (SP-TPS) tensor as a function of the number of sites turned to be closely related to the presence of an energy gap between the ground-state and the first excited-state at the thermodynamic limit. Indeed, a gapped energy spectrum is associated to a linear growth of the SP-TPS tensor with the number of sites. On the other hand, in gapless situations, the spread presents a faster-than-linear growth, resulting in the divergence of its per-site value. Finally, for the case of a high-spin wave function, an analytical expression of the dependence of the SP-TPS on the number of sites n and the total spin-projection S{sub z} has been derived.
The q-deformed SU(2) Heisenberg model in 3-dimensions
International Nuclear Information System (INIS)
Lu Zhongyi; Yan Hong.
1991-07-01
A q-deformed SU(2) Heisenberg (3-dimensional) spin model is set up, and the q-deformed spin-wave solution is obtained through the q-analogous Holstein-Primakoff transformation. The result is given for small γ = ln q, which is the quantity characterizing the nonlinearity of the Hamiltonian. A mean-field treatment is arranged to preserved (at least some of) the nonlinearity, and the ordinary ferromagnet ground state is shown as the exact ground state of the new system. Interesting results are obtained for this nonlinear model: (i) There is an energy gap between the ground state and the first excited one, thus the ground state is stable under small perturbation of the background; (ii) the specific heat per volume is modified by a small term proportional to the 1/2-th power of temperature and the square of γ, which is qualitatively different from the conventional model, and (iii) the magnetization M(T) is modified by a factor that depends on γ. (author). 16 refs
Persistence of the gapless spin liquid in the breathing kagome Heisenberg antiferromagnet
Iqbal, Yasir; Poilblanc, Didier; Thomale, Ronny; Becca, Federico
2018-03-01
The nature of the ground state of the spin S =1 /2 Heisenberg antiferromagnet on the kagome lattice with breathing anisotropy (i.e., with different superexchange couplings J▵ and J▿ within elementary up- and down-pointing triangles) is investigated within the framework of Gutzwiller projected fermionic wave functions and Monte Carlo methods. We analyze the stability of the U(1 ) Dirac spin liquid with respect to the presence of fermionic pairing that leads to a gapped Z2 spin liquid. For several values of the ratio J▿/J▵ , the size scaling of the energy gain due to the pairing fields and the variational parameters are reported. Our results show that the energy gain of the gapped spin liquid with respect to the gapless state either vanishes for large enough system size or scales to zero in the thermodynamic limit. Similarly, the optimized pairing amplitudes (responsible for opening the spin gap) are shown to vanish in the thermodynamic limit. Our outcome is corroborated by the application of one and two Lanczos steps to the gapless and gapped wave functions, for which no energy gain of the gapped state is detected when improving the quality of the variational states. Finally, we discuss the competition with the "simplex" Z2 resonating-valence-bond spin liquid, valence-bond crystal, and nematic states in the strongly anisotropic regime, i.e., J▿≪J▵ .
Atanasov, Victor; Saxena, Avadh
2011-05-04
Adopting a purely two-dimensional relativistic equation for graphene's carriers contradicts the Heisenberg uncertainty principle since it requires setting the off-the-surface coordinate of a three-dimensional wavefunction to zero. Here we present a theoretical framework for describing graphene's massless relativistic carriers in accordance with this most fundamental of all quantum principles. A gradual confining procedure is used to restrict the dynamics onto a surface and normal to the surface parts, and in the process the embedding of this surface into the three-dimensional world is accounted for. As a result an invariant geometric potential arises in the surface part which scales linearly with the mean curvature and shifts the Fermi energy of the material proportional to bending. Strain induced modification of the electronic properties or 'straintronics' is clearly an important field of study in graphene. This opens an avenue to producing electronic devices: micro- and nano-electromechanical systems (MEMS and NEMS), where the electronic properties are controlled by geometric means and no additional alteration of graphene is necessary. The appearance of this geometric potential also provides us with clues as to how quantum dynamics looks in the curved space-time of general relativity. In this context we explore a two-dimensional cross-section of the wormhole geometry, realized with graphene as a solid state thought experiment. © 2011 IOP Publishing Ltd
The Heisenberg Uncertainty Principle and the Nyquist-Shannon Sampling Theorem
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Millette P. A.
2013-07-01
Full Text Available The derivation of the Heisenberg Uncertainty Principle (HUP from the Uncertainty Theorem of Fourier Transform theory demonstrates that the HUP arises from the dependency of momentum on a wave number that exists at the quantum level. It also establishes that the HUP is purely a relationship between the eﬀective widths of Fourier transform pairs of variables (i.e. conjugate variables. We note that the HUP is not a quantum mechanical measurement principle per se. We introduce the Quantum Mechanical equivalent of the Nyquist-Shannon Sampling Theorem of Fourier Transform theory, and show that it is a better principle to describe the measurement limitations of Quantum Mechanics. We show that Brillouin zones in Solid State Physics are a manifestation of the Nyquist-Shannon Sampling Theorem at the quantum level. By comparison with other ﬁelds where Fourier Transform theory is used, we propose that we need todiscern between measurement limitations and inherent limitations when interpreting the impact of the HUP on the nature of the quantum level. We further propose that while measurement limitations result in our perception of indeterminism at the quantum level, there is no evidence that there are any inherent limitations at the quantum level, based on the Nyquist-Shannon Sampling Theorem
Emergent Criticality and Ricci Flow in a 2D Frustrated Heisenberg Model
Orth, Peter P.
2014-03-01
In most systems that exhibit order at low temperatures, the order occurs in the elementary degrees of freedom such as spin or charge. Prominent examples are magnetic or superconducting states of matter. In contrast, emergent order describes the phenomenon where composite objects exhibit longer range correlations. Such emergent order has been suspected to occur in a range of correlated materials. One specific example are spin systems with competing interactions, where long-range discrete order in the relative orientation of spins may occur. Interestingly, this order parameter may induce other phase transitions as is the case for the nematic transition in the iron pnictides. In this talk, we introduce and discuss a system with emergent Z6 symmetry, a two-dimensional frustrated Heisenberg antiferromagnet on the windmill lattice consisting of interpenetrating honeycomb and triangular lattices. The multiple spin stiffnesses can be captured in terms of a four-dimensional metric tensor, and the renormalization group flow of the stiffnesses is described by the Ricci flow of the metric tensor. The key result is a decoupling of an emergent collective degree of freedom given by the relative phase of spins on different sublattices. In particular, our results reveal a sequence of two Berezinskii-Kosterlitz-Thouless phase transitions that bracket a critical phase.
Kim, Sanghoon
2018-04-19
Chiral spin textures of a ferromagnetic layer in contact to a heavy non-magnetic metal, such as Néel-type domain walls and skyrmions, have been studied intensively because of their potential for future nanomagnetic devices. The Dyzaloshinskii–Moriya interaction (DMI) is an essential phenomenon for the formation of such chiral spin textures. In spite of recent theoretical progress aiming at understanding the microscopic origin of the DMI, an experimental investigation unravelling the physics at stake is still required. Here we experimentally demonstrate the close correlation of the DMI with the anisotropy of the orbital magnetic moment and with the magnetic dipole moment of the ferromagnetic metal in addition to Heisenberg exchange. The density functional theory and the tight-binding model calculations reveal that inversion symmetry breaking with spin–orbit coupling gives rise to the orbital-related correlation. Our study provides the experimental connection between the orbital physics and the spin–orbit-related phenomena, such as DMI.
Hastatic order in the two-channel Kondo-Heisenberg model
Zhang, Guanghua; Flint, Rebecca
Understanding Kondo physics in materials with non-Kramers doublets requires understanding the two channel Kondo effect, as valence fluctuations are from a non-Kramers doublet ground state to an excited Kramers doublet. Here, the development of a heavy Fermi liquid requires a channel symmetry breaking hybridization. This order, which breaks both single and double time-reversal symmetry was recently introduced as hastatic order. Here we employ an SU(N) fermionic mean-field treatment of the two-channel Kondo-Heisenberg model on a square lattice to explore properties of hastatic order and particularly the competition between the hastatic order and magnetism, as embodied by a spin liquid phase in our model. For simplicity, only a momentum independent hybrization between the non-Kramers f2 states and conduction electrons is considered. Upon varying the RKKY coupling and conduction electron density, we find both uniform and staggered [ Q = (π , π) ] hastatic order, in addition to the spin liquid phase, with metal-insulator transitions, including Lifshitz transitions inside the staggered phase. As the band degeneracy of the conduction electron bands is broken, the uniform hastatic order is partially suppressed compared to the staggered phase.
Petersen, Jakob; Pollak, Eli
2015-12-14
One of the challenges facing on-the-fly ab initio semiclassical time evolution is the large expense needed to converge the computation. In this paper, we suggest that a significant saving in computational effort may be achieved by employing a semiclassical initial value representation (SCIVR) of the quantum propagator based on the Heisenberg interaction representation. We formulate and test numerically a modification and simplification of the previous semiclassical interaction representation of Shao and Makri [J. Chem. Phys. 113, 3681 (2000)]. The formulation is based on the wavefunction form of the semiclassical propagation instead of the operator form, and so is simpler and cheaper to implement. The semiclassical interaction representation has the advantage that the phase and prefactor vary relatively slowly as compared to the "standard" SCIVR methods. This improves its convergence properties significantly. Using a one-dimensional model system, the approximation is compared with Herman-Kluk's frozen Gaussian and Heller's thawed Gaussian approximations. The convergence properties of the interaction representation approach are shown to be favorable and indicate that the interaction representation is a viable way of incorporating on-the-fly force field information within a semiclassical framework.
NMR evidence for peculiar spin gaps in a doped S=1/2 Heisenberg spin chain
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Utz, Yannic; Rudisch, Christian; Hammerath, Franziska; Grafe, Hans-Joachim; Mohan, Ashwin; Ribeiro, Patrick; Hess, Christian; Wolter, Anja; Kataev, Vladislav; Nishimoto, Satoshi; Drechsler, Stefan-Ludwig; Buechner, Bernd [IFW Dresden (Germany); Singh, Surjeet [Indian Institute of Science Education and Research, Pune (India); Saint-Martin, Romuald; Revcolevschi, Alexandre [Laboratoire de Physico-Chimie de l' Etat Solide, Universite Paris-Sud, Orsay (France)
2012-07-01
We present {sup 63}Cu Nuclear Magnetic Resonance (NMR) measurements on undoped, Ca-doped and Ni-doped SrCuO{sub 2} single crystals. SrCuO{sub 2} is a good realization of a one-dimensional S=1/2 Heisenberg spin chain. This is manifested by the theoretically-expected temperature-independent NMR spin-lattice relaxation rate T{sub 1}{sup -1}. In Sr{sub 0.9}Ca{sub 0.1}CuO{sub 2} an exponential decrease of T{sub 1}{sup -1} below 90 K evidences the opening of a gap in the spin excitation spectrum, which amounts to {Delta}=50 K. DMRG calculations are presented to discuss the origin of this spin gap. New results on SrCu{sub 0.99}Ni{sub 0.01}O{sub 2} also indicate the presence of a spin gap, which is twice as large as in Sr{sub 0.9}Ca{sub 0.1}CuO{sub 2}, despite the minor doping level of Ni compared to Ca. We discuss different possible impacts of Ca (S=0) and Ni (S=1) doping on structural and magnetic properties of the parent compound.
McLeod, David; McLeod, Roger
2008-04-01
The electron model used in our other joint paper here requires revision of some foundational physics. That electron model followed from comparing the experimentally proved results of human vision models using spatial Fourier transformations, SFTs, of pincushion and Hermann grids. Visual systems detect ``negative'' electric field values for darker so-called ``illusory'' diagonals that are physical consequences of the lens SFT of the Hermann grid, distinguishing this from light ``illusory'' diagonals. This indicates that oppositely directed vectors of the separate illusions are discretely observable, constituting another foundational fault in quantum mechanics, QM. The SFT of human vision is merely the scaled SFT of QM. Reciprocal space results of wavelength and momentum mimic reciprocal relationships between space variable x and spatial frequency variable p, by the experiment mentioned. Nobel laureate physicist von B'ek'esey, physiology of hearing, 1961, performed pressure input Rect x inputs that the brain always reports as truncated Sinc p, showing again that the brain is an adjunct built by sight, preserves sign sense of EMF vectors, and is hard wired as an inverse SFT. These require vindication of Schr"odinger's actual, but incomplete, wave model of the electron as having physical extent over the wave, and question Heisenberg's uncertainty proposal.
Multiloop Euler-Heisenberg Lagrangians, Schwinger Pair Creation, and the Photon S-Matrix
Huet, I.; de Traubenberg, M. R.; Schubert, C.
2017-03-01
Although the perturbation series in quantum electrodynamics has been studied for eighty years concerning its high-order behavior, our present understanding is still poorer than for many other field theories. An interesting case is Schwinger pair creation in a constant electric field, which may possibly provide a window to high loop orders; simple non-perturbative closed-form expressions have been conjectured for the pair creation rate in the weak field limit, for scalar QED in 1982 by Affleck, Alvarez, and Manton, and for spinor QED by Lebedev and Ritus in 1984. Using Borel analysis, these can be used to obtain non-perturbative information on the on-shell renormalized N-photon amplitudes at large N and low energy. This line of reasoning also leads to a number of nontrivial predictions for the effective QED Lagrangian in either four or two dimensions at any loop order, and preliminary results of a calculation of the three-loop Euler-Heisenberg Lagrangian in two dimensions are presented.
Heisenberg spin-1/2 XXZ chain in the presence of electric and magnetic fields
Thakur, Pradeep; Durganandini, P.
2018-02-01
We study the interplay of electric and magnetic order in the one-dimensional Heisenberg spin-1/2 XXZ chain with large Ising anisotropy in the presence of the Dzyaloshinskii-Moriya (DM) interaction and with longitudinal and transverse magnetic fields, interpreting the DM interaction as a coupling between the local electric polarization and an external electric field. We obtain the ground state phase diagram using the density matrix renormalization group method and compute various ground state quantities like the magnetization, staggered magnetization, electric polarization and spin correlation functions, etc. In the presence of both longitudinal and transverse magnetic fields, there are three different phases corresponding to a gapped Néel phase with antiferromagnetic (AF) order, gapped saturated phase, and a critical incommensurate gapless phase. The external electric field modifies the phase boundaries but does not lead to any new phases. Both external magnetic fields and electric fields can be used to tune between the phases. We also show that the transverse magnetic field induces a vector chiral order in the Néel phase (even in the absence of an electric field) which can be interpreted as an electric polarization in a direction parallel to the AF order.
Energy Technology Data Exchange (ETDEWEB)
Neto, Minos A., E-mail: minos@pq.cnpq.br [Departamento de Fisica, Universidade Federal do Amazonas, 3000, Japiim, Manaus, 69077-000 AM (Brazil); Roberto Viana, J., E-mail: vianafisica@bol.com.br [Departamento de Fisica, Universidade Federal do Amazonas, 3000, Japiim, Manaus, 69077-000 AM (Brazil); Ricardo de Sousa, J., E-mail: jsousa@edu.ufam.br [Departamento de Fisica, Universidade Federal do Amazonas, 3000, Japiim, Manaus, 69077-000 AM (Brazil); National Institute of Science and Technology for Complex Systems, 3000, Japiim, Manaus, 69077-000 AM (Brazil)
2012-08-15
In this work we study the critical behavior of the quantum spin-1/2 anisotropic Heisenberg antiferromagnet in the presence of a longitudinal field on a body centered cubic (bcc) lattice as a function of temperature, anisotropy parameter ({Delta}) and magnetic field (H), where {Delta}=0 and 1 correspond the isotropic Heisenberg and Ising models, respectively. We use the framework of the differential operator technique in the effective-field theory with finite cluster of N=4 spins (EFT-4). The staggered m{sub s}=(m{sub A}-m{sub B})/2 and total m=(m{sub A}+m{sub B})/2 magnetizations are numerically calculated, where in the limit of m{sub s}{yields}0 the critical line T{sub N}(H,{Delta}) is obtained. The phase diagram in the T-H plane is discussed as a function of the parameter {Delta} for all values of H Element-Of [0,H{sub c}({Delta})], where H{sub c}({Delta}) correspond the critical field (T{sub N}=0). Special focus is given in the low temperature region, where a reentrant behavior is observed around of H=H{sub c}({Delta}){>=}H{sub c}({Delta}=1)=8J in the Ising limit, results in accordance with Monte Carlo simulation, and also was observed for all values of {Delta} Element-Of [0,1]. This reentrant behavior increases with increase of the anisotropy parameter {Delta}. In the limit of low field, our results for the Heisenberg limit are compared with series expansion values. - Highlights: Black-Right-Pointing-Pointer In the lat decade there has been a great interest in the physics of the quantum phase transition in spins system. Black-Right-Pointing-Pointer Effective-field theory in cluster with N=4 spins is generalized to treat the quantum spin-1/2 Heisenberg model. Black-Right-Pointing-Pointer We have obtained phase diagram at finite temperature for the quantum spin-1/2 antiferromagnet Heisenberg model as a bcc lattice.
Spin transport in the two-dimensional quantum disordered anisotropic Heisenberg model
Energy Technology Data Exchange (ETDEWEB)
Lima, L.S. [Departamento de Física e Matemática, Centro Federal de Educação Tecnológica de Minas Gerais, 30510-000 Belo Horizonte, MG (Brazil); Pires, A.S.T.; Costa, B.V. [Departamento de Física ICEx, UFMG, CP 702, 31270-901 Belo Horizonte, MG (Brazil)
2014-12-15
We use the self consistent harmonic approximation together with the Linear Response Theory to study the effect of nonmagnetic disorder on spin transport in the quantum diluted two-dimensional anisotropic Heisenberg model with spin S=1 in a square lattice. The model has a BKT transition at zero dilution. We calculate the regular part of the spin conductivity σ{sup reg}(ω) and the Drude weight D{sub S}(T) as a function of the non-magnetic concentration, x. Our calculations show that the spin conductivity drops abruptly to zero at x{sub c}{sup SCHA}≈0.5 indicating that the system changes from an ideal spin conductor state to an insulator. This value is far above the site percolation threshold x{sub c}{sup site}≈0.41. Although the SCHA fails in determining precisely the percolation threshold, both the spin conductivity and the Drude weight show a quite regular behavior inside 0≤x≤x{sub c}{sup SCHA} indicating that the transition stays in the same universality class all along the interval. - Highlights: • The site dilution generates a large influence on regular part of the spin conductivity, σ{sup reg}(ω), and in the Drude weight, D(T). • In a concentration of impurities about x≈0.5, the regular part of the spin conductivity and the Drude weight fall to zero. • In this point we have a change in the state of the system from an ideal spin conductor to a spin insulator.
Arian Zad, Hamid; Ananikian, Nerses
2018-04-01
The mixed spin-(1,1/2) Ising–Heisenberg double sawtooth ladder containing a mixture of both spin-1 and spin-1/2 nodal atoms, and the spin-1/2 interstitial dimers are approximately solved by the transfer-matrix method. Here, we study in detail the ground-state phase diagrams, also influences of the bilinear exchange coupling on the rungs and cyclic four-spin exchange interaction in square plaquette of each block on the magnetization and magnetic susceptibility of the suggested ladder at low temperature. Such a double sawtooth ladder may be found in a Shastry-Sutherland lattice-type. In spite of the spin ordering of odd and even blocks being different from each other, due to the commutation relation between all different block Hamiltonians, phase diagrams, magnetization behavior and thermodynamic properties of the model are the same for odd and even blocks. We show that at low temperature, both exchange couplings can change the quality and quantity of the magnetization plateaus versus the magnetic field changes. Specially, we find a new magnetization plateau M/Ms= 5/6 for this model. Besides, we examine the magnetic susceptibility and specific heat of the model in detail. It is proven that behaviors of the magnetization and the magnetic susceptibility coincide at low temperature. The specific heat displays diverse temperature dependencies, which include a Schottky-type peak at a special temperature interval. We observe that with increase of the bilinear exchange coupling on the rungs, second peak temperature dependence grows.
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Strečka, Jozef, E-mail: jozef.strecka@upjs.sk [Department of Theoretical Physics and Astrophysics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 040 01 Košice (Slovakia); Alécio, Raphael Cavalcante; Lyra, Marcelo L. [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceio-AL (Brazil); Rojas, Onofre [Departamento de Física, Universidade Federal de Lavras, 37200-000 Lavras-MG (Brazil)
2016-07-01
The spin-1/2 Ising–Heisenberg three-leg tube composed of the Heisenberg spin triangles mutually coupled through the Ising inter-triangle interaction is exactly solved in a zero magnetic field. By making use of the local conservation for the total spin on each Heisenberg spin triangle the model can be rigorously mapped onto a classical composite spin-chain model, which is subsequently exactly treated through the transfer-matrix method. The ground-state phase diagram, correlation functions, concurrence, Bell function, entropy and specific heat are examined in detail. It is shown that the spin frustration represents an indispensable ground for a thermal entanglement, which is quantified by the quantum concurrence. The specific heat displays diverse temperature dependences, which may include a sharp low-temperature peak mimicking a temperature-driven first-order phase transition. It is convincingly evidenced that this anomalous peak originates from massive thermal excitations from the doubly degenerate ground state towards an excited state with a high macroscopic degeneracy due to chiral degrees of freedom of the Heisenberg spin triangles. - Highlights: • Spin-1/2 Ising–Heisenberg three-leg tube is exactly solved in a zero magnetic field. • Thermal entanglement is only present in a frustrated part of the parameter space. • Spin frustration and thermal entanglement show antagonistic reentrance. • Specific heat may display a sharp narrow peak due to massive thermal excitations.
Energy Technology Data Exchange (ETDEWEB)
Kosmachev, O. A.; Krivtsova, A. V.; Fridman, Yu. A., E-mail: yuriifridman@gmail.com [Vernadskii Crimea Federal University (Russian Federation)
2016-02-15
We study the effect of interionic anisotropy on the phase states of a non-Heisenberg ferromagnet with magnetic ion spin S = 1. It is shown that depending on the relation between the interionic anisotropy constants, uniaxial and angular ferromagnetic and nonmagnetic phases exist in the system. We analyze the dynamic properties of the system in the vicinity of orientational phase transitions, as well as a phase transition in the magnetic moment magnitude. It is shown that orientational phase transitions in ferromagnetic and nematic phases can be first- as well as second-order.
International Nuclear Information System (INIS)
Staunton, L.P.
1976-01-01
The covariant operator Heisenberg equations of motion and commutation relations following from positive-energy wave equations are obtained. The resulting theory is identical to that of a dual string model restricted to excitations of only the lowest normal modes. It is suggested that recent classical Dirac-bracket formulations of the full dual string are subject to reinterpretation, and are apparently Poincare covariant in four dimensions. The nucleus of the complete set of covariant quantum string relations is obtained from the restricted model, and it is shown that covariant normal-mode operators and those of the null plane cannot both have simple creation-operator character
Yang, Qi; Cao, Yue; Chen, Shiyin; Teng, Yue; Meng, Yanli; Wang, Gangcheng; Sun, Chunfang; Xue, Kang
2018-03-01
In this paper, we construct a new set of orthonormal topological basis states for six qubits with the topological single loop d = 2. By acting on the subspace, we get a new five-dimensional (5D) reduced matrix. In addition, it is shown that the Heisenberg XXX spin-1/2 chain of six qubits can be constructed from the Temperley-Lieb algebra (TLA) generator, both the energy ground state and the spin singlet states of the system can be described by the set of topological basis states.
Directory of Open Access Journals (Sweden)
J. Strečka
2012-12-01
Full Text Available The spin-1/2 Ising-Heisenberg model on diamond-like decorated Bethe lattices is exactly solved in the presence of the longitudinal magnetic field by combining the decoration-iteration mapping transformation with the method of exact recursion relations. In particular, the ground state and low-temperature magnetization process of the ferrimagnetic version of the considered model is investigated in detail. Three different magnetization scenarios with up to two consecutive fractional magnetization plateaus were found, whereas the intermediate magnetization plateau may either correspond to the classical ferrimagnetic spin arrangement and/or the field-induced quantum ferrimagnetic spin ordering without any classical counterpart.
Bethe Ansatz for two-magnon scattering states in 2D and 3D Heisenberg-Ising ferromagnets
Bibikov, P. N.
2017-01-01
Various versions of the Bethe ansatz are suggested for evaluation of scattering two-magnon states in 2D and 3D Heisenberg-Ising ferromagnets. It is shown that for 2D square (3D qubic) finite-periodic or infinite lattices about a half (3/4) of states have a correctly 2D- (3D-) generalized Bethe form. The remaining scattering states are treated (on the infinite lattices only) within the degenerative discrete-diffractive modification of the Bethe ansatz previously suggested by the author.
Magnetic field-driven 3D-Heisenberg-like phase transition in single crystalline helimagnet FeGe
Xu, Lisha; Fan, Jiyu; Sun, Weifeng; Zhu, Yan; Hu, Dazhi; Liu, Jindong; Ji, Yanda; Shi, Daning; Yang, Hao
2017-07-01
Significant microscopic information about fundamental magnetic interactions of magnetic materials is probed via the critical behavior of paramagnetic-ferromagnetic phase transition. In this work, we demonstrate that the critical behavior of cubic single crystalline FeGe belongs to the isotropic 3D-Heisenberg universality class by measuring the field dependence of magnetic entropy change. The above transition is one of the magnetic field-driven phase transitions but has a feature of the crossover from first- to second-order phase transition. A phenomenological model based on the evolution of magnetic skyrmions was proposed to qualitatively understand the phase transition.
International Nuclear Information System (INIS)
Bobak, Andrej; Dely, Jan; Pokorny, Vladislav
2010-01-01
The effects of both an exchange anisotropy and a single-ion anisotropy on the magnetic susceptibility of the mixed spin-1 and spin- 1/2 Heisenberg model are investigated by the use of an Oguchi approximation. Particular emphasis is given to the simple cubic lattice with coordination number z = 6 for which the magnetic susceptibility is determined numerically. Anomalous behaviour in the thermal variation of the magnetic susceptibility in the low-temperature region is found due to the applied negative single-ion anisotropy field strength. Also, the difference between the behaviours of the magnetic susceptibility of the Heisenberg and Ising models is discussed.
Spinon confinement in a quasi-one-dimensional anisotropic Heisenberg magnet
Bera, A. K.; Lake, B.; Essler, F. H. L.; Vanderstraeten, L.; Hubig, C.; Schollwöck, U.; Islam, A. T. M. N.; Schneidewind, A.; Quintero-Castro, D. L.
2017-08-01
Confinement is a process by which particles with fractional quantum numbers bind together to form quasiparticles with integer quantum numbers. The constituent particles are confined by an attractive interaction whose strength increases with increasing particle separation and, as a consequence, individual particles are not found in isolation. This phenomenon is well known in particle physics where quarks are confined in baryons and mesons. An analogous phenomenon occurs in certain spatially anisotropic magnetic insulators. These can be thought of in terms of weakly coupled chains of spins S =1 /2 , and a spin flip thus carries integer spin S =1 . The collective excitations in these systems, called spinons, turn out to carry fractional spin quantum number S =1 /2 . Interestingly, at sufficiently low temperatures the weak coupling between chains can induce an attractive interaction between pairs of spinons that increases with their separation and thus leads to confinement. In this paper, we employ inelastic neutron scattering to investigate the spinon-confinement process in the quasi-one-dimensional, spin-1/2 antiferromagnet with Heisenberg-Ising (XXZ) anisotropy SrCo2V2O8 . A wide temperature range both above and below the long-range ordering temperature TN=5.2 K is explored. Spinon excitations are observed above TN in quantitative agreement with established theory. Below TN pairs of spinons are confined and two sequences of meson-like bound states with longitudinal and transverse polarizations are observed. Several theoretical approaches are used to explain the data. These are based on a description in terms of a one-dimensional, S =1 /2 XXZ antiferromagnetic spin chain, where the interchain couplings are modeled by an effective staggered magnetic mean field. A wide range of exchange anisotropies are investigated and the parameters specific to SrCo2V2O8 are identified. Recently developed theoretical technique based on tangent-space matrix product states gives a very
Sun, Fadi; Ye, Jinwu; Liu, Wu-Ming
2016-07-01
In this paper, we study the rotated ferromagnetic Heisenberg model (RFHM) in two different transverse fields, hx and hz, which can be intuitively visualized as studying spin-orbit coupling (SOC) effects in two-dimensional (2D) Ising or anisotropic X Y model in a transverse field. At a special SOC class, it was found in our previous work [Phys. Rev. A 92, 043609 (2015), 10.1103/PhysRevA.92.043609] that the RFHM at a zero field owns an exact spin-orbit coupled ground state called the Y -x state. It supports not only the commensurate magnons (called C -C0 and C -Cπ ), but also the incommensurate magnons (called C-IC). These magnons are nonrelativistic, not embedded in the exact ground state, so need to be thermally excited or generated by various external probes. Their dramatic response under a longitudinal hy field was recently worked out by Sun et al. [arXiv:1502.05338]. Here we find they respond very differently under the two transverse fields. Any hx (hz) introduces quantum fluctuations to the ground state and changes the collinear Y -x state to a canted coplanar Y X -x (Y Z -x ) state. The C -C0,C -Cπ , and C-IC magnons become relativistic and sneak into the quantum ground state. We determine the competing boundaries among the C -C0,C -Cπ , and C-IC magnons, especially the detailed dispersions of the C-IC magnons inside the canted phases, which can be mapped out by the transverse spin structure factors. As hx (hz) increases further, the C -C0 magnons always win the competition and emerge as the seeds to drive a transition from the Y X -x (or Y Z -x ) to the ferromagnetic along the X (orZ ) direction called the X -FM (or Z -FM) phase. We show that the transition is in the 3D Ising universality class and it becomes the 3D X Y transition at the two Abelian points. We evaluate these magnons' contributions to magnetization and specific heat at low temperatures which can be measured by various established experimental techniques. The nature of the finite
Dynamical properties of the S =1/2 random Heisenberg chain
Shu, Yu-Rong; Dupont, Maxime; Yao, Dao-Xin; Capponi, Sylvain; Sandvik, Anders W.
2018-03-01
We study dynamical properties at finite temperature (T ) of Heisenberg spin chains with random antiferromagnetic exchange couplings, which realize the random singlet phase in the low-energy limit, using three complementary numerical methods: exact diagonalization, matrix-product-state algorithms, and stochastic analytic continuation of quantum Monte Carlo results in imaginary time. Specifically, we investigate the dynamic spin structure factor S (q ,ω ) and its ω →0 limit, which are closely related to inelastic neutron scattering and nuclear magnetic resonance (NMR) experiments (through the spin-lattice relaxation rate 1 /T1 ). Our study reveals a continuous narrow band of low-energy excitations in S (q ,ω ) , extending throughout the q space, instead of being restricted to q ≈0 and q ≈π as found in the uniform system. Close to q =π , the scaling properties of these excitations are well captured by the random-singlet theory, but disagreements also exist with some aspects of the predicted q dependence further away from q =π . Furthermore we also find spin diffusion effects close to q =0 that are not contained within the random-singlet theory but give non-negligible contributions to the mean 1 /T1 . To compare with NMR experiments, we consider the distribution of the local relaxation rates 1 /T1 . We show that the local 1 /T1 values are broadly distributed, approximately according to a stretched exponential. The mean 1 /T1 first decreases with T , but below a crossover temperature it starts to increase and likely diverges in the limit of a small nuclear resonance frequency ω0. Although a similar divergent behavior has been predicted and experimentally observed for the static uniform susceptibility, this divergent behavior of the mean 1 /T1 has never been experimentally observed. Indeed, we show that the divergence of the mean 1 /T1 is due to rare events in the disordered chains and is concealed in experiments, where the typical 1 /T1 value is accessed.
Energy Technology Data Exchange (ETDEWEB)
Nicolescu, Basarab [LPNHE, Unite de Recherche des Universites Paris 6 et Paris 7, associee au CNRS, Theory Group, Universite Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 05 (France)
2004-07-01
We consider several classes of analytic parametrizations of hadronic scattering amplitudes (the COMPETE analysis), and compare their predictions to all available forward data (pp, {pi}p, Kp, {gamma}p, {gamma}{gamma}, {sigma}p). Although these parametrizations are very close for {radical}s {>=} 9 GeV, it turns out that they differ markedly at low energy, where a universal Pomeron term {approx} ln{sup 2} s enables one to extend the fit down to {radical}s = 4 GeV. We present predictions on the total cross sections and on the ratio of the real part to the imaginary part of the elastic amplitude ({rho} parameter) for present and future pp colliders, and on total cross sections for {gamma}p {yields} hadrons at cosmic-ray energies and for it{gamma}{gamma} {yields} hadrons up to {radical}s = 1 TeV. The ln{sup 2} s behaviour of total cross sections, first obtained by Heisenberg 50 years ago, receives now increased interest both on phenomenological and theoretical levels. We present a modification of the Heisenberg's model in connection with the presence of glueballs and we show that it leads to a realistic description of all existing hadron total cross-sections data, in agreement with the COMPETE analysis.
Directory of Open Access Journals (Sweden)
J. Strečka
2012-12-01
Full Text Available The ferrimagnetic spin-1/2 chain composed of alternating Ising and Heisenberg spins in an arbitrarily oriented magnetic field is exactly solved using the spin-rotation transformation and the transfer-matrix method. It is shown that the low-temperature magnetization process depends basically on a spatial orientation of the magnetic field. A sharp stepwise magnetization curve with a marked intermediate plateau, which emerges for the magnetic field applied along the easy-axis direction of the Ising spins, becomes smoother and the intermediate plateau shrinks if the external field is tilted from the easy-axis direction. The magnetization curve of a polycrystalline system is also calculated by performing powder averaging of the derived magnetization formula. The proposed spin-chain model brings an insight into high-field magnetization data of 3d-4f bimetallic polymeric compound Dy(NO3(DMSO2Cu(opba(DMSO2, which provides an interesting experimental realization of the ferrimagnetic chain composed of two different but regularly alternating spin-1/2 magnetic ions Dy3+ and Cu2+ that are reasonably approximated by the notion of Ising and Heisenberg spins, respectively.
DEFF Research Database (Denmark)
Clarke, S.J.; Harrison, A.; Mason, T.E.
1999-01-01
Copper(II) formate tetrahydrate (CFTH) is a model square S = 1/2 Heisenberg antiferromagnet with T-N = 16.54 +/- 0.05 K. The dispersion of spin-waves in the magnetic layers of a fully deuterated sample of this material has been mapped at 4.3 K by inelastic neutron scattering from the zone centre...
Energy Technology Data Exchange (ETDEWEB)
Brymora, Katarzyna; Calvayrac, Florent, E-mail: Florent.Calvayrac@univ-lemans.fr
2017-07-15
Highlights: • A new method is given to extract surface anisotropies from ab initio calculations. • Heisenberg model for magnetic clusters and surfaces is validated in simple cases. • Ligands, metallic clusters, or coatings degrade the validity of the Heisenberg model. • Values for surface anisotropies, volume anisotropies, exchange constants are computed. • Results are in agreement with experimental data, previous theoretical findings. - Abstract: We performed ab initio computations of the magnetic properties of simple iron oxide clusters and slabs. We considered an iron oxide cluster functionalized by a molecule or glued to a gold cluster of the same size. We also considered a magnetite slab coated by cobalt oxide or a mixture of iron oxide and cobalt oxide. The changes in magnetic behavior were explored using constrained magnetic calculations. A possible value for the surface anisotropy was estimated from the fit of a classical Heisenberg model on ab initio results. The value was found to be compatible with estimations obtained by other means, or inferred from experimental results. The addition of a ligand, coating, or of a metallic nanoparticle to the systems degraded the quality of the description by the Heisenberg Hamiltonian. Proposing a change in the anisotropies allowing for the proportion of each transition atom we could get a much better description of the magnetism of series of hybrid cobalt and iron oxide systems.
International Nuclear Information System (INIS)
Grimm, Uwe; Schuetz, Gunter
1992-09-01
The finite-size spectra of the spin-1/2 XXZ Heisenberg chain with toroidal boundary conditions and an even number of sites provide a projection mechanism yielding the spectra of models with central charge c q [sl(2)] quantum algebra transformations. (author)
Chen, Wei; 飛田, 和男; Sanctuary, Bryan C.
2008-01-01
Original Paper :Critical Properties of Spin-1 Antiferromagnetic Heisenberg Chains with Bond Alternation and Uniaxial Single-Ion-Type AnisotropyWei Chen, Kazuo Hida and Bryan Clifford Sanctuary Journal of the Physical Society of Japan 69 (2000) pp.237-241
DEFF Research Database (Denmark)
Lefmann, K.; Rischel, C.
1996-01-01
-28. We have studied S-zz(q,omega) for the Heisenberg chain in zero field, and from finite-size scaling we have obtained a limiting behavior that for large omega deviates from the conjecture proposed earlier by Muller ct al. For both chains we describe the behavior of S-zz(q,omega) and S...
International Nuclear Information System (INIS)
Fongang, Bernard; Labaye, Yvan; Calvayrac, Florent; Zekeng, Serge; Grenèche, Jean-Marc
2012-01-01
We present a numerical study of the magnetic structure of nanostructured iron fluoride, using the Monte Carlo Metropolis simulated annealing technique and a classical Heisenberg Hamiltonian with superexchange angle dependent interactions. The parameters are adjusted on experimental results, and the atomic structure and topology taken from a previous atomistic model of grain boundaries in the same system. We find perfect antiferromagnetic crystalline grains and a disordered magnetic configuration (speromagnetic) at the grain boundary, in agreement with experimental features. Both the lowest magnetic energy and the rate of magnetic frustration are found to be dependent on the relative disorientation of crystalline grains, i.e. on the cationic topology. We conclude on possible extensions of the model.
Emergent spin-1 trimerized valence bond crystal in the spin-1/2 Heisenberg model on the star lattice
Ran, Shi-Ju; Li, Wei; Gong, Shou-Shu; Weichselbaum, Andreas; von Delft, Jan; Su, Gang
2018-02-01
We explore the frustrated spin-1/2 Heisenberg model on the star lattice with antiferromagnetic (AF) couplings inside each triangle and ferromagnetic (FM) intertriangle couplings (Jefrustration from the AF interactions inside each triangle, but trigger a fully gapped inversion-symmetry-breaking trimerized valence bond crystal (TVBC) with emergent spin-1 degrees of freedom. We discover that with strengthening Je, the system exhibits a universal scaling behavior either with or without a magnetic field h : the order parameter, the five critical fields that separate the Je-h ground-state phase diagram into six phases, and the excitation gap obtained by low-temperature specific heat, all depend exponentially on Je. Our work implies that the spin-1 VBCs can be stabilized by introducing small FM couplings in the geometrically frustrated spin-1/2 systems.
DEFF Research Database (Denmark)
Gammelmark, Søren; Mølmer, Klaus
2011-01-01
to determine the complete phase diagram of the system. The analysis reveals both first- and second-order Dicke phase transitions into a super-radiant state, and the cavity mean field in this regime acts as an effective magnetic field, which restricts the Ising chain dynamics to parameter ranges away from......We investigate the thermodynamics of a combined Dicke and Ising model that exhibits a rich phenomenology arising from the second-order and quantum phase transitions from the respective models. The partition function is calculated using mean-field theory, and the free energy is analyzed in detail...... the Ising phase transition. Physical systems with first-order phase transitions are natural candidates for metrology and calibration purposes, and we apply filter theory to show that the sensitivity of the physical system to temperature and external fields reaches the 1/N Heisenberg limit....
Nori, F.; Merlin, R.; Haas, S.; Sandvick, A.; Dagotto, E.
1996-03-01
We calculate(F. Nori, R.Merlin, S. Haas, A.W. Sandvik, and E. Dagotto, Physical Review Letters) 75, 553 (1995). the Raman spectrum of the two-dimensional (2D) spin-1/2 Heisenberg antiferromagnet by exact diagonalization and quantum Monte Carlo techniques on clusters of up to 144 sites. On a 16-site cluster, we consider the phonon-magnon interaction which leads to random fluctuations of the exchange integral. Results are in good agreement with experiments on various high-Tc precursors, such as La_2CuO4 and YBa_2Cu_3O_6.2. In particular, our calculations reproduce the broad lineshape of the two-magnon peak, the asymmetry about its maximum, the existence of spectral weight at high energies, and the observation of nominally forbidden A_1g scattering.
J{sub 1x}-J{sub 1y}-J{sub 2} square-lattice anisotropic Heisenberg model
Energy Technology Data Exchange (ETDEWEB)
Pires, A.S.T., E-mail: antpires@frisica.ufmg.br
2017-08-01
Highlights: • We use the SU(3) Schwinger boson formalism. • We present the phase diagram at zero temperature. • We calculate the quadrupole structure factor. - Abstract: The spin one Heisenberg model with an easy-plane single-ion anisotropy and spatially anisotropic nearest-neighbor coupling, frustrated by a next-nearest neighbor interaction, is studied at zero temperature using a SU(3) Schwinger boson formalism (sometimes also referred to as flavor wave theory) in a mean field approximation. The local constraint is enforced by introducing a Lagrange multiplier. The enlarged Hilbert space of S = 1 spins lead to a nematic phase that is ubiquitous to S = 1 spins with single ion anisotropy. The phase diagram shows two magnetically ordered phase, separated by a quantum paramagnetic (nematic) phase.
International Nuclear Information System (INIS)
Law, J M; Benner, H; Kremer, R K
2013-01-01
The temperature dependence of the spin susceptibilities of S = 1, 3/2 , 2, 5/2 and 7/2 Heisenberg antiferromagnetic 1D spins chains with nearest-neighbor coupling was simulated via quantum Monte Carlo calculations, within the reduced temperature range of 0.005 ≤ T* ≤ 100, and fitted to a Padé approximation with deviations between the simulated and fitted data of the same order of magnitude as or smaller than the quantum Monte Carlo simulation error. To demonstrate the practicality of our theoretical findings, we compare these results with the susceptibility of the well known 1D chain compound TMMC ([(CH 3 ) 4 N[MnCl 3
Reyes Toca, Joan Paola; Rivera Moreira, Sandra Mirella
2016-01-01
Este proyecto de investigación tuvo como objetivo determinar la incidencia de la calidad del servicio en el nivel de competitividad de la línea naviera XYZ, para ello se inició con el diseño de un marco teórico en base a factores, metodologías y estrategias relacionadas con la problemática planteada. La metodología de investigación consistió en establecer el nivel de competitividad de la naviera respecto a otras del sector, aplicando la matriz y el cuestionario del modelo gerencial. Los resul...
Mi, Bin-Zhou; Feng, Cui-Ju; Luo, Jian-Guo; Hu, De-Zhi
2018-01-01
In recent years, some theoretical interests have been focused on the binary alloy nanotubes and nanowires with mixed spins. Compared with ferrimagnetic nanowires, few studies have been done on ferrimagnetic nanotubes. In this paper, the magnetic properties of a mixed spin-(2, 3/2) Heisenberg single-walled nanotube superlattice are calculated by use of the double-time Green's function method within the random phase approximation and the Anderson and Callen's decoupling. Magnetic compensation and critical properties are obtained for a wide range of parameters in the Hamiltonian, and magnetic phase diagrams are plotted in the related planes. For Heisenberg single-walled nanotube superlattice model with Néel-type magnetic structure, anisotropy must be taken into account, and the easy-axis single-ion anisotropy is considered in this paper. The next nearest neighbor exchange interactions Jbb and/or single-ion anisotropy strength Db of the smaller spin sublattice were necessary in order to obtain a compensation point. The influence of the wall diameter number of the tubes, m, an important parameter of the system, on the compensation behavior is considered. Calculation shows that as Jbb and Db are fixed, only when m is beyond a certain minimum value, mmin, can compensation temperature Tcom appears, where the next nearest neighbor exchange interactions Jaa and single-ion anisotropy strength Da of the larger spin sublattice are absent. The compensation temperature and critical temperature increase with m rising, which indicates that the longitudinal correlation effect is enhanced and the fluctuation effect is weakened with the increase of m.
Heisenberg spin-glass behaviour in Ga0.99Yb0.01FeO3
Neacsa, Daniela Maria; Gruener, Gisèle; Hebert, Sylvie; Soret, Jean-Claude
2017-06-01
The dynamic and static magnetic properties of Ga0.99Yb0.01FeO3 are studied in detail using ac susceptibility and dc magnetization measurements. The study shows that the compound undergoes a spin-glass freezing at Tg ≈ 213 K . The dynamic scaling analysis of ac susceptibility data reveals typical features characteristic of canonical spin-glasses, i.e., relaxation time τ∗ ∼10-14 s , critical exponent νz = 4.1 ± 0.2 , and frequency sensitivity parameter δf ∼10-3 within three frequency decades. The analysis of the critical behaviour of the static nonlinear susceptibility yields the critical exponents γ = 4.3 ± 0.1, β = 1.0 ± 0.1 , and δ = 5.5 ± 0.5 , which lie between those typical of three-dimensional (3D) weakly anisotropic Heisenberg and Ising spin glasses. The analysis of the field-cooled and zero-field-cooled magnetization data allows to define two characteristic temperatures depending on the applied magnetic field. The upper one, Tirr(H) , is the threshold temperature corresponding to the appearance of weak irreversibility, whereas the lower one, Ts(H) , marks the onset of strong irreversibility. The resulting field-temperature phase diagram turns out to be in good quantitative agreement with the mean-field predictions for 3D Heisenberg spin-glass with random magnetic anisotropy, and appears consistent with the chiral driven freezing scenario.
Wan, Kianna; Nataf, Pierre; Mila, Frédéric
2017-09-01
We present a method for the exact diagonalization of the SU (N ) Heisenberg interaction Hamiltonian using Young tableaus to work directly in each irreducible representation of the global SU (N ) group. This generalized scheme is applicable to chains consisting of several particles per site, with any SU (N ) symmetry at each site. Extending some of the key results of substitutional analysis, we demonstrate how basis states can be efficiently constructed for the relevant SU (N ) subsector, which, especially with increasing values of N or numbers of sites, has a much smaller dimension than the full Hilbert space. This allows us to analyze systems of larger sizes than can be handled by existing techniques. We apply this method to investigate the presence of edge states in SU (N ) Heisenberg and Affleck-Kennedy-Lieb-Tasaki Hamiltonians.
Brymora, Katarzyna; Calvayrac, Florent
2017-07-01
We performed ab initio computations of the magnetic properties of simple iron oxide clusters and slabs. We considered an iron oxide cluster functionalized by a molecule or glued to a gold cluster of the same size. We also considered a magnetite slab coated by cobalt oxide or a mixture of iron oxide and cobalt oxide. The changes in magnetic behavior were explored using constrained magnetic calculations. A possible value for the surface anisotropy was estimated from the fit of a classical Heisenberg model on ab initio results. The value was found to be compatible with estimations obtained by other means, or inferred from experimental results. The addition of a ligand, coating, or of a metallic nanoparticle to the systems degraded the quality of the description by the Heisenberg Hamiltonian. Proposing a change in the anisotropies allowing for the proportion of each transition atom we could get a much better description of the magnetism of series of hybrid cobalt and iron oxide systems.
International Nuclear Information System (INIS)
Greven, M.; Birgeneau, R.J.; Endoh, Y.; Kastner, M.A.; Keimer, B.; Matsuda, M.; Shirane, G.; Thurston, T.R.
1994-01-01
We report a neutron scattering study of the spin correlations in the model 2D, S=1/2, square-lattice Heisenberg antiferromagnetic Sr 2 CuO 2 Cl 2 . The spin correlation lengths obtained agree quantitatively with values deduced from Monte Carlo simulations over a wide range of temperature. The combined data, which cover the length scale from 1 to 200 lattice constants, are predicted accurately with no adjustable parameters by renormalized classical theory for the quantum nonlinear sigma model
Sex Discrimination? The XYZ Affair.
Hoffmann, Carl; Reed, John Shelton
1981-01-01
Describes an investigation of sex discrimination at a large American corporation. The investigation found that although fewer women than men were promoted, this was due to greater interest in promotion expressed by men, rather than to discrimination by the company. Argues against criteria applied by federal agencies to prove discrimination. (GC)
International Nuclear Information System (INIS)
Voorhoeve, J.C.
1986-01-01
The goal of this thesis is to clarify the dynamic properties of a one-dimensional S=1/2 isotropic Heisenberg antiferromagnet (HAFM). The physical realization chosen for this model system is CuSO 4 .5H 2 O. The experimental information about the dynamical properties of the electron spin system is obtained from longitudinal proton spin relaxation measurements. In ch.2 the experimental set up is described including the 3 He- 4 He dilution refrigerator for obtaining the required low temperatures, and the rotatable superconducting split-coil magnet. In ch.3 the problems are treated which occur when nuclear relaxation experiments are performed in the long-range order state of CuSO 4 .5H 2 O and an experimental method is described to measure the proton spin-lattice relaxation time T 1 supplying a minimum of energy to the nuclear spin system. In ch.4 continuous-wave NMR experiments on CuSO 4 .5H 2 O are described. In ch. 5 experimental results on the relaxation rate T 1 -1 above and in the vicinity of the phase transition are described and in ch.6 experimental results in the LRO state are presented and discussed. (Auth.)
Energy Technology Data Exchange (ETDEWEB)
Lapa, Rodrigo S.; Mendonça, Griffith [Departamento de Fi' sica, Universidade Federal de Minas Gerais, CP 702, 30161-970 Belo Horizonte, MG (Brazil); Universidade Federal do Amazonas, Departamento de Fi' sica, 3000, Japiim, 69077-000 Manaus, AM (Brazil); Roberto Viana, J. [Universidade Federal do Amazonas, Departamento de Fi' sica, 3000, Japiim, 69077-000 Manaus, AM (Brazil); Ricardo de Sousa, J., E-mail: jsousa@ufam.edu.br [Universidade Federal do Amazonas, Departamento de Fi' sica, 3000, Japiim, 69077-000 Manaus, AM (Brazil); National Institute of Science and Technology for Complex Systems, Universidade Federal do Amazonas, Departamento de Fisica, 3000, Japiim, 69077-000 Manaus, AM (Brazil)
2014-11-15
We have studied the quantum spin-1/2 frustrated Heisenberg model with two ferromagnetic interactions: nearest-neighbor (NN) with different coupling strengths J{sub 1} and J{sub 1}{sup ′} along x and y directions, respectively, competing with a next-nearest-neighbor (NNN) with coupling J{sub 2}. Using the effective-field theory we obtain the ground-state phase diagram in the (λ,α) space, where λ=J{sub 1}{sup ′}/J{sub 1} and α=J{sub 2}/J{sub 1}. Depending on the values of λ and α we observe three different states: ferromagnetic (F), collinear ferromagnetic (CF) and quantum paramagnetic (QP). We observe a QP state between the ordered F and CF phases in the region λ{sub 1}<λ<1 (λ{sub 1}≃0.62). - Highlights: • We study the ferromagnetic J{sub 1}−J{sub 1}{sup ′}−J{sub 2} model on an anisotropic square lattice by using effective-field theory. • We obtain the ground phase diagram in the λ−α plane (λ=J{sub 1}{sup ′}/J{sub 1} and α=J{sub 2}/J{sub 1}). • A comparison with the results of the antiferromagnetic J{sub 1}−J{sub 1}{sup ′}−J{sub 2} model. • We propose a functional for the free energy.
Tribedi, Amit; Bose, Indrani
2009-01-01
We consider a two-chain, spin- (1)/(2) antiferromagnetic Heisenberg spin ladder in an external magnetic field H . The spin ladder is known to undergo second-order quantum phase transitions (QPTs) at two critical values Hc1 and Hc2 of the magnetic field. There are now known examples of strongly coupled (where the rung exchange interaction is much stronger than the nearest-neighbor intrachain exchange interaction) organic ladder compounds in which QPTs have been experimentally observed. In this paper, we investigate whether well-known bipartite entanglement meaures such as one-site von Neumann entropy, two-site von Neumann entropy, and concurrence develop special features close to the quantum critical points. As suggested by an earlier theorem, the first derivatives of the measures with respect to magnetic field are expected to diverge as H→Hc1 and H→Hc2 . Based on numerical diagonalization data and a mapping of the strongly coupled ladder Hamiltonian onto the XXZ chain Hamiltonian, for which several analytical results are known, we find that the derivatives of the entanglement measures diverge as H→Hc2 but remain finite as H→Hc1 . The reason for this discrepancy is analyzed. We further calculate two recently proposed quantum information theoretic measures, the reduced fidelity and reduced fidelity susceptibility, and show that these measures provide appropriate signatures of the QPTs occuring at the critical points H=Hc1 and H=Hc2 .
Zad, Hamid Arian; Movahhedian, Hossein
2016-08-01
Heat capacity of a mixed-three-spin (1/2,1,1/2) antiferromagnetic XXX Heisenberg chain is precisely investigated by use of the partition function of the system for which, spins (1,1/2) have coupling constant J1 and spins (1/2,1/2) have coupling constant J2. We verify tripartite entanglement for the model by means of the convex roof extended negativity (CREN) and concurrence as functions of temperature T, homogeneous magnetic field B and the coupling constants J1 and J2. As shown in our previous work, [H. A. Zad, Chin. Phys. B 25 (2016) 030303.] the temperature, the magnetic field and the coupling constants dependences of the heat capacity for such spin system have different behaviors for the entangled and separable states, hence, we did some useful comparisons between this quantity and negativities of its organized bipartite (sub)systems at entangled and separable states. Here, we compare the heat capacity of the mixed-three-spin (1/2,1,1/2) system with the CREN and the tripartite concurrence (as measures of the tripartite entanglement) at low temperature. Ground state phase transitions, and also, transition from ground state to some excited states are explained in detail for this system at zero temperature. Finally, we investigate the heat capacity behavior around those critical points in which these quantum phase transitions occur.
Buessen, Finn Lasse; Roscher, Dietrich; Diehl, Sebastian; Trebst, Simon
2018-02-01
The pseudofermion functional renormalization group (pf-FRG) is one of the few numerical approaches that has been demonstrated to quantitatively determine the ordering tendencies of frustrated quantum magnets in two and three spatial dimensions. The approach, however, relies on a number of presumptions and approximations, in particular the choice of pseudofermion decomposition and the truncation of an infinite number of flow equations to a finite set. Here we generalize the pf-FRG approach to SU (N )-spin systems with arbitrary N and demonstrate that the scheme becomes exact in the large-N limit. Numerically solving the generalized real-space renormalization group equations for arbitrary N , we can make a stringent connection between the physically most significant case of SU(2) spins and more accessible SU (N ) models. In a case study of the square-lattice SU (N ) Heisenberg antiferromagnet, we explicitly demonstrate that the generalized pf-FRG approach is capable of identifying the instability indicating the transition into a staggered flux spin liquid ground state in these models for large, but finite, values of N . In a companion paper [Roscher et al., Phys. Rev. B 97, 064416 (2018), 10.1103/PhysRevB.97.064416] we formulate a momentum-space pf-FRG approach for SU (N ) spin models that allows us to explicitly study the large-N limit and access the low-temperature spin liquid phase.
Ito, Kazuhiro; Shimahara, Hiroshi
2016-02-01
We examine the mean field theory of a uniaxial coupled Heisenberg antiferromagnet with two subsystems, one of which consists of strongly interacting small spins and the other consists of weakly interacting large spins. We reanalyze the experimental data of specific heat and magnetic susceptibility obtained by previous authors for the organic compound λ-(BETS)2FeCl4 at low temperatures, where BETS stands for bis(ethylenedithio)tetraselenafulvalene. The model parameters for this compound are evaluated, where the applicability of the theory is checked. As a result, it is found that J1 ≫ J12 ≫ J2, where J1, J2, and J12 denote the exchange coupling constant between π spins, that between 3d spins, and that between π and 3d spins, respectively. At the low-temperature limit, both sublattice magnetizations of the 3d and π spins are saturated, and the present model is reduced to the Schottky model, which successfully explains experimental observations in previous studies. As temperature increases, fluctuations of 3d spins increase, while π spins remain almost saturated. Near the critical temperature, both spins fluctuate significantly, and thus the mean field approximation breaks down. It is revealed that the magnetic anisotropy, which may be crucial to the antiferromagnetic long-range order, originates from J12 rather than from J2 and that the angle between the magnetic easy-axis and the crystal c-axis is approximately 26-27° in the present effective model.
Directory of Open Access Journals (Sweden)
M.R. Setare
2017-01-01
Full Text Available In this paper we study the near horizon symmetry algebra of the non-extremal black hole solutions of the Chern–Simons-like theories of gravity, which are stationary but are not necessarily spherically symmetric. We define the extended off-shell ADT current which is an extension of the generalized ADT current. We use the extended off-shell ADT current to define quasi-local conserved charges such that they are conserved for Killing vectors and asymptotically Killing vectors which depend on dynamical fields of the considered theory. We apply this formalism to the Generalized Minimal Massive Gravity (GMMG and obtain conserved charges of a spacetime which describes near horizon geometry of non-extremal black holes. Eventually, we find the algebra of conserved charges in Fourier modes. It is interesting that, similar to the Einstein gravity in the presence of negative cosmological constant, for the GMMG model also we obtain the Heisenberg algebra as the near horizon symmetry algebra of the black flower solutions. Also the vacuum state and all descendants of the vacuum have the same energy. Thus these zero energy excitations on the horizon appear as soft hairs on the black hole.
Thermal Entanglement in XXZ Heisenberg Model for Coupled Spin-Half and Spin-One Triangular Cell
Najarbashi, Ghader; Balazadeh, Leila; Tavana, Ali
2018-01-01
In this paper, we investigate the thermal entanglement of two-spin subsystems in an ensemble of coupled spin-half and spin-one triangular cells, (1/2, 1/2, 1/2), (1/2, 1, 1/2), (1, 1/2, 1) and (1, 1, 1) with the XXZ anisotropic Heisenberg model subjected to an external homogeneous magnetic field. We adopt the generalized concurrence as the measure of entanglement which is a good indicator of the thermal entanglement and the critical points in the mixed higher dimensional spin systems. We observe that in the near vicinity of the absolute zero, the concurrence measure is symmetric with respect to zero magnetic field and changes abruptly from a non-null to null value for a critical magnetic field that can be signature of a quantum phase transition at finite temperature. The analysis of concurrence versus temperature shows that there exists a critical temperature, that depends on the type of the interaction, i.e. ferromagnetic or antiferromagnetic, the anisotropy parameter and the strength of the magnetic field. Results show that the pairwise thermal entanglement depends on the third spin which affects the maximum value of the concurrence at absolute zero and at quantum critical points.
Impurity effects in a S=1/2 Heisenberg spin chain probed by {sup 63}Cu NMR
Energy Technology Data Exchange (ETDEWEB)
Utz, Yannic; Bruening, Eva Maria; Hammerath, Franziska; Rudisch, Christian; Grafe, Hans-Joachim; Mohan, Ashwin; Hess, Christian; Nishimoto, Satoshi; Drechsler, Stefan-Ludwig; Buechner, Bernd [IFW Dresden (Germany); Saint-Martin, Romuald; Revcolevschi, Alexandre [LPCES, Orsay (France)
2013-07-01
We present {sup 63}Cu NMR measurements on undoped, Ni doped and Mg doped SrCuO{sub 2} single crystals. SrCuO{sub 2} is a good realization of a one-dimensional S=1/2 Heisenberg spin chain. This is confirmed by the theoretically-expected temperature independent NMR spin-lattice relaxation rate T{sup -1}{sub 1}. Doping with Ni, which can be regarded as a S=1 impurity, has a major impact on the magnetic properties of the spin chains. On the one hand, this is manifested by unusual features in the NMR spectra below 100 K, revealing the existence of an impurity-induced local alternating magnetisation. On the other hand, exponentially decaying spin lattice relaxation rates towards low temperatures indicate the opening of a spin gap similar to Ca doped SrCuO{sub 2}. Mg doping (S=0) has, however, no influence on the magnetic properties of the spin chains. Neither the NMR spectra nor the spin lattice relaxation rates differ from those measured on pure SrCuO{sub 2}. While the different impact of Ni and Mg doping on the spin chains could be explained by their different impurity spins, the opening of a spin gap in case of Ni doping is totally unexpected and not yet understood.
Djoufack, Z I; Tala-Tebue, E; Nguenang, J P; Kenfack-Jiotsa, A
2016-10-01
We report in this work, an analytical study of quantum soliton in 1D Heisenberg spin chains with Dzyaloshinsky-Moriya Interaction (DMI) and Next-Nearest-Neighbor Interactions (NNNI). By means of the time-dependent Hartree approximation and the semi-discrete multiple-scale method, the equation of motion for the single-boson wave function is reduced to the nonlinear Schrödinger equation. It comes from this present study that the spectrum of the frequencies increases, its periodicity changes, in the presence of NNNI. The antisymmetric feature of the DMI was probed from the dispersion curve while changing the sign of the parameter controlling it. Five regions were identified in the dispersion spectrum, when the NNNI are taken into account instead of three as in the opposite case. In each of these regions, the quantum model can exhibit quantum stationary localized and stable bright or dark soliton solutions. In each region, we could set up quantum localized n-boson Hartree states as well as the analytical expression of their energy level, respectively. The accuracy of the analytical studies is confirmed by the excellent agreement with the numerical calculations, and it certifies the stability of the stationary quantum localized solitons solutions exhibited in each region. In addition, we found that the intensity of the localization of quantum localized n-boson Hartree states increases when the NNNI are considered. We also realized that the intensity of Hartree n-boson states corresponding to quantum discrete soliton states depend on the wave vector.
Konstantinidis, N P
2015-02-25
The antiferromagnetic Heisenberg model on the icosahedron presents unconventional properties at the classical and quantum level, which originate in the frustrated nature of the interactions between the spins. Here we examine the importance of the connectivity of the icosahedron for the appearance of a magnetization discontinuity as a function of an external field which separates two families of lowest energy configurations. We also investigate the transition from the classical to the quantum limit. The influence of connectivity on the magnetic properties is revealed by considering the cluster as being made up of a closed strip of a triangular lattice with two additional spins attached. The classical magnetization discontinuity is shown to evolve continuously from the discontinuity effected by these two spins when they are uncoupled to the cluster. In the second part the transition from the classical to the quantum limit is examined by focusing on the low energy spectrum, taking fully into account the spatial and the spin symmetry of the model in the characterization of the states. A symmetry analysis of the highly degenerate lowest energy classical manifold identifies as its direct fingerprint the low energy quantum states for spin magnitude as low as s = 1, with the latter following a tower of states behavior which relates to the icosahedron having a structure reminiscent of a depleted triangular lattice. The classical character of the AHM for small s is also detected on the ground state energy and correlation functions. On the other hand the classical magnetization discontinuity in a field eventually disappears for small s, after a weak reentrant behavior.
Short-range correlations in d-f cyanido-bridged assemblies with XY and XY-Heisenberg anisotropy.
Tanase, Stefania; Evangelisti, Marco; de Jongh, L Jos
2011-09-07
Two new d-f cyanido-bridged 1D assemblies [RE(pzam)(3)(H(2)O)Mo(CN)(8)]·H(2)O (RE = Sm(III), Er(III)) were synthesized and their magneto-structural properties have been studied by field-dependent magnetization and specific heat measurements at low temperatures (≥0.3 K). Below ≈ 10 K the ground state of both the Sm(III) and Er(III) ions is found to be a Kramers doublet with effective spin S = 1/2. From analyses of the low-temperature magnetic specific heat and magnetization the exchange coupling between these RE(III) effective spins and the Mo(v) spins S = 1/2 along the structural chains has been determined. It is found to be antiferromagnetic, with J(∥)/k(B) = -2.6 K and Ising-Heisenberg symmetry of the interaction (J(∥)/J(⊥) = 0.3) for RE = Sm(III), whereas the compound with RE = Er(III) behaves as a pure XY chain, with J(⊥)/k(B) = -1.0 K. For the compound [Sm(pzam)(3)(H(2)O)Mo(CN)(8)]·H(2)O a small λ-type anomaly in the specific heat is observed at about 0.6 K, which is ascribed to a transition to long-range magnetic ordering induced by weak interchain interactions of dipolar origin. No evidence for 3D interchain magnetic ordering is found in the Er(III) analogue. This journal is © The Royal Society of Chemistry 2011
Shan, Xiao; Xiahou, Chengkui; Connor, J N L
2018-01-03
In earlier research, we have demonstrated that broad "hidden" rainbows can occur in the product differential cross sections (DCSs) of state-to-state chemical reactions. Here we ask the question: can pronounced and localized rainbows, rather than broad hidden ones, occur in reactive DCSs? Further motivation comes from recent measurements by H. Pan and K. Liu, J. Phys. Chem. A, 2016, 120, 6712, of a "bulge" in a reactive DCS, which they conjecture is a rainbow. Our theoretical approach uses a "weak" version of Heisenberg's scattering matrix program (wHSMP) introduced by X. Shan and J. N. L. Connor, Phys. Chem. Chem. Phys., 2011, 13, 8392. This wHSMP uses four general physical principles for chemical reactions to suggest simple parameterized forms for the S matrix; it does not employ a potential energy surface. We use a parameterization in which the modulus of the S matrix is a smooth-step function of the total angular momentum quantum number, J, and (importantly) its phase is a cubic polynomial in J. We demonstrate for a Legendre partial wave series (PWS) the existence of pronounced rainbows, supernumerary rainbows, and other interference effects, in reactive DCSs. We find that reactive rainbows can be more complicated in their structure than the familiar rainbows of elastic scattering. We also analyse the angular scattering using Nearside-Farside (NF) PWS theory and NF PWS Local Angular Momentum (LAM) theory, including resummations of the PWS. In addition, we apply full and NF asymptotic (semiclassical) rainbow theories to the PWS - in particular, the uniform Airy and transitional Airy approximations for the farside scattering. This lets us prove that structure in the DCSs are indeed rainbows, supernumerary rainbows as well as other interference effects.
Li, P. H. Y.; Bishop, R. F.
2018-03-01
We implement the coupled cluster method to very high orders of approximation to study the spin-1/2 J1 -J2 Heisenberg model on a cross-striped square lattice. Every nearest-neighbour pair of sites on the square lattice has an isotropic antiferromagnetic exchange bond of strength J1 > 0 , while the basic square plaquettes in alternate columns have either both or neither next-nearest-neighbour (diagonal) pairs of sites connected by an equivalent frustrating bond of strength J2 ≡ αJ1 > 0 . By studying the magnetic order parameter (i.e., the average local on-site magnetization) in the range 0 ≤ α ≤ 1 of the frustration parameter we find that the quasiclassical antiferromagnetic Néel and (so-called) double Néel states form the stable ground-state phases in the respective regions α α1bc = 0.615(5) . The double Néel state has Néel (⋯ ↑↓↑↓ ⋯) ordering along the (column) direction parallel to the stripes of squares with both or no J2 bonds, and spins alternating in a pairwise (⋯ ↑↑↓↓↑↑↓↓ ⋯) fashion along the perpendicular (row) direction, so that the parallel pairs occur on squares with both J2 bonds present. Further explicit calculations of both the triplet spin gap and the zero-field uniform transverse magnetic susceptibility provide compelling evidence that the ground-state phase over all or most of the intermediate regime α1ac state with no discernible long-range magnetic order.
Disentanglement of two qubits coupled to an XY spin chain: Role of quantum phase transition
International Nuclear Information System (INIS)
Yuan Zigang; Li Shushen; Zhang Ping
2007-01-01
We study the disentanglement evolution of two spin qubits which interact with a general XY spin-chain environment. The dynamical process of the disentanglement is numerically and analytically investigated in the vicinity of a quantum phase transition (QPT) of the spin chain in both weak and strong coupling cases. We find that the disentanglement of the two spin qubits may be greatly enhanced by the quantum critical behavior of the environmental spin chain. We give a detailed analysis to facilitate the understanding of the QPT-enhanced decaying behavior of the coherence factor. Furthermore, the scaling behavior in the disentanglement dynamics is also revealed and analyzed
Coxeter groups A4, B4 and D4 for two-qubit systems
Indian Academy of Sciences (India)
A simple technique is employed to construct the unitary matrix representations of the groups, based on quaternionic transformation of the usual reflection matrices. The von Neumann entropy of each reduced density matrix is calculated. It is shown that these unitary matrix representations are naturally related to various ...
Czech Academy of Sciences Publication Activity Database
Bartkiewicz, K.; Černoch, Antonín; Lemr, K.; Miranowicz, A.
2016-01-01
Roč. 6, Jan (2016), 1-7, č. článku 19610. ISSN 2045-2322 R&D Projects: GA ČR GAP205/12/0382 Institutional support: RVO:68378271 Keywords : entangled photons * state tomography Subject RIV: BH - Optics, Masers, Lasers Impact factor: 4.259, year: 2016
A relevant two qubit Bell inequality inequivalent to the CHSH inequality
International Nuclear Information System (INIS)
Collins, Daniel; Gisin, Nicolas
2004-01-01
We computationally investigate the complete polytope of Bell inequalities for two particles with small numbers of possible measurements and outcomes. Our approach is limited by Pitowsky's connection of this problem to the computationally hard NP problem. Despite this, we find that there are very few relevant inequivalent inequalities for small numbers. For example, in the case with three possible 2-outcome measurements on each particle, there is just one new inequality. We describe mixed 2-qubit states which violate this inequality but not the CHSH. The new inequality also illustrates a sharing of bi-partite non-locality between three qubits: something not seen using the CHSH inequality. It also inspires us to discover a class of Bell inequalities with m possible n-outcome measurements on each particle
Generation of Werner-like stationary states of two qubits in a thermal reservoir
International Nuclear Information System (INIS)
Jakobczyk, Lech
2010-01-01
The dynamics of entanglement between two-level atoms immersed in the common photon reservoir at finite temperature is investigated. It is shown that in the regime of strong correlations there are nontrivial asymptotic states which can be interpreted in terms of thermal generalization of Werner states.
Generation of Werner-like stationary states of two qubits in a thermal reservoir
Energy Technology Data Exchange (ETDEWEB)
Jakobczyk, Lech, E-mail: ljak@ift.uni.wroc.p [Institute of Theoretical Physics, University of Wroclaw, Plac Maxa Borna 9, 50-204 Wroclaw (Poland)
2010-01-14
The dynamics of entanglement between two-level atoms immersed in the common photon reservoir at finite temperature is investigated. It is shown that in the regime of strong correlations there are nontrivial asymptotic states which can be interpreted in terms of thermal generalization of Werner states.
Quantum discord dynamics of two qubits in single-mode cavities
International Nuclear Information System (INIS)
Wang Chen; Chen Qing-Hu
2013-01-01
The dynamics of quantum discord for two identical qubits in two independent single-mode cavities and a common single-mode cavity are discussed. For the initial Bell state with correlated spins, while the entanglement sudden death can occur, the quantum discord vanishes only at discrete moments in the independent cavities and never vanishes in the common cavity. Interestingly, quantum discord and entanglement show opposite behavior in the common cavity, unlike in the independent cavities. For the initial Bell state with anti-correlated spins, quantum discord and entanglement behave in the same way for both independent cavities and a common cavity. It is found that the detunings always stabilize the quantum discord. (general)
Shimada, Alisa; Nakano, Hiroki; Sakai, Tôru; Yoshimura, Kazuyoshi
2018-03-01
The S = 1/2 triangular-lattice Heisenberg antiferromagnet with distortion is investigated by the numerical-diagonalization method. The examined distortion type is √{3} × √{3} . We study the case when the distortion connects the undistorted triangular lattice and the dice lattice. For the intermediate phase reported previously in this system, we obtain results of the boundaries of the intermediate phase for a larger system than those in the previous report and examine the system size dependence of the boundaries in detail. We also report the specific heat of this system, which shows a marked peak structure related to the appearance of the intermediate state.
Hirose, Yuhei; Oguchi, Akihide; Fukumoto, Yoshiyuki
2017-12-01
We study spin-1/2 Heisenberg antiferromagnets on a diamond-like-decorated square lattice perturbed by two kinds of further neighbor couplings. In our previous study [https://doi.org/10.7566/JPSJ.85.094002" xlink:type="simple">J. Phys. Soc. Jpn. 85, 094002 (2016)], the second-order effective Hamiltonian for the Heisenberg model perturbed by a further neighbor coupling was found to be a square-lattice quantum-dimer model with a finite hopping amplitude, t > 0, and no dimer-dimer interaction, v = 0. In this study, we introduce another kind of further neighbor coupling and show that it leads to an attractive interaction between dimers, which suggests the stabilization of the columnar phase of the square-lattice quantum-dimer model. The calculated v/t is presented as a function of the ratio of the two exchange parameters in the Heisenberg model.
Energy Technology Data Exchange (ETDEWEB)
Maeter, H.; Klauss, H.H. [Institut fuer Festkoerperphysik, TU Dresden (Germany); Zvyagin, A.A. [Institut fuer Festkoerperphysik, TU Dresden (Germany); Institute for Low Temperature Physics and Engineering, NAS of Ukraine, Kharkov (Ukraine); Luetkens, H.; Pascua, G.; Shermadini, Z. [Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, Villigen (Switzerland); Hess, C.; Hlubek, N.; Buechner, B. [Leibniz-Institut fuer Festkoerper- und Werkstoffforschung, Dresden (Germany); Saint-Matin, R.; Revcolevschi, A. [Laboratoire de Physico-Chimie de L' Etat Solide, ICMMO, UMR 8182, Universite Paris-Sud, Orsay (France)
2011-07-01
For one-dimensional quantum spin chain systems recent experimental and theoretical studies indicate unexpectedly large, in some cases diverging spin and heat transport coefficients. Local probes, like e.g. muon spin relaxation ({mu}SR) can indirectly characterize the spin transport properties of low dimensional systems via the magnetic field dependence of the spin lattice relaxation rate {lambda}(B). For diffusive spin transport {lambda}{proportional_to}B{sup -0.5} is expected. For the ground state of the isotropic spin-1/2 antiferromagnetic Heisenberg chain the eigenstates of the Heisenberg Hamiltonian dominate the spin transport, which is then ballistic. Using the Mueller ansatz {lambda}{proportional_to}B{sup -1} is expected in this case. For SrCuO{sub 2} we find {lambda}{proportional_to}B{sup -0.9(3)}. This result is temperature independent for 5 K{<=}T {<=}300 K. Within conformal field theory and using the Mueller ansatz we conclude ballistic spin transport in SrCuO{sub 2}.
Rao, Wen-Jia; Zhang, Guang-Ming; Yang, Kun
2016-03-01
Applying a symmetric bulk bipartition to the one-dimensional Affleck-Kennedy-Lieb-Tasaki valence-bond solid (VBS) states for the integer spin-S Haldane gapped phase, we can create an array of fractionalized spin-S /2 edge states with the super unit cell l in the reduced bulk system, and the topological properties encoded in the VBS wave functions can be revealed. The entanglement Hamiltonian (EH) with even l corresponds to the quantum antiferromagnetic Heisenberg spin-S /2 model. For the even integer spins, the EH still describes the Haldane gapped phase. For the odd integer spins, however, the EH just corresponds to the quantum antiferromagnetic Heisenberg half-odd integer-spin model with spinon excitations, characterizing the critical point separating the topological Haldane phase from the trivial gapped phase. Our results thus demonstrate that the topological bulk property not only determines its fractionalized edge states but also the quantum criticality associated with the topological phase, where the elementary excitations are precisely those fractionalized edge degrees of freedom confined in the bulk of the topological phase.
Arian Zad, Hamid; Ananikian, Nerses
2017-11-01
We consider a symmetric spin-1/2 Ising-XXZ double sawtooth spin ladder obtained from distorting a spin chain, with the XXZ interaction between the interstitial Heisenberg dimers (which are connected to the spins based on the legs via an Ising-type interaction), the Ising coupling between nearest-neighbor spins of the legs and rungs spins, respectively, and additional cyclic four-spin exchange (ring exchange) in the square plaquette of each block. The presented analysis supplemented by results of the exact solution of the model with infinite periodic boundary implies a rich ground state phase diagram. As well as the quantum phase transitions, the characteristics of some of the thermodynamic parameters such as heat capacity, magnetization and magnetic susceptibility are investigated. We prove here that among the considered thermodynamic and thermal parameters, solely heat capacity is sensitive versus the changes of the cyclic four-spin exchange interaction. By using the heat capacity function, we obtain a singularity relation between the cyclic four-spin exchange interaction and the exchange coupling between pair spins on each rung of the spin ladder. All thermal and thermodynamic quantities under consideration should be investigated by regarding those points which satisfy the singularity relation. The thermal entanglement within the Heisenberg spin dimers is investigated by using the concurrence, which is calculated from a relevant reduced density operator in the thermodynamic limit.
Indian Academy of Sciences (India)
two sources, (1) electromagnetism and (2) atomic the- ory. Electromagnetism, that unified electricity and mag-. netiSlTI, showed that moving charges produce magnetic fields and moving magnets produce emfs in conductors. The fact that electrons (discovered in 1897) reside in atoms directed attention to the question ...
Indian Academy of Sciences (India)
Li and Si are the quantum numbers of orbital and spin angular momenta respectively, 'h' is the Planck constant and the summation in (1) is evaluated for all the 'z' electrons in the atom. Whether an atom or a molecule has a permanent dipole moment or not is decided by whether the sum in (1) is non zero or not - a scheme.
Heisenberg's Invention of Matrices
Indian Academy of Sciences (India)
Richard Feynman once said: “nobody understands quantummechanics”. Still, those who devised it are perhaps the onesclosest to understanding their creation. It suggests that wheneverthe weirdness of quantum mechanics haunts you, it isbetter to go back to its creators in terms of their originalpublications. In the present ...
Heisenberg's Invention of Matrices
Indian Academy of Sciences (India)
the weirdness of going from classical observables to quantum operators. It is well known that quantum mechanics was formulated in two different mathematical forms, one of which is known as 'matrix mechanics' and the other as 'wave mechanics'. Initially, there was a divided opinion about which of these formulations repre-.
International Nuclear Information System (INIS)
Igarashi, J.; Watabe, A.
1991-01-01
Quantum corrections to the longitudinal spin-correlation function and the spin-stiffness constant are calculated up to 1/(2S) 2 in a two-dimensional Heisenberg antiferromagnet at zero temperature by using the Holstein-Primakoff transformation. The equal-time longitudinal spin-correlation function is found to compensate almost entirely the reduction caused by the second-order correction in the transverse spin-correlation function, making the spherically averaged correlation function very close to the value given by linear spin-wave theory. In the spin-stiffness constant, a partial cancellation is found between the ''paramagnetic'' and ''diamagnetic'' terms, leading to a small second-order correction
Directory of Open Access Journals (Sweden)
Dzhunushaliev Vladimir
2017-01-01
Full Text Available The nonperturbative quantization technique à la Heisenberg is applied for the SU(3 gauge theory. The operator Yang-Mills equation and corresponding infinite set of equations for all Green’s functions are considered. Gauge degrees of freedom are splitted into two groups: (1 Aμa ∈ SU (2 × U(1 ⊂ SU(3; (2 coset degrees of freedom SU(3/SU(2 × U(1. Using some assumptions about 2- and 4-point Green’s functions, the infinite set of equations is truncated to two equations. The first equation is the SU(2 × U(1 Yang-Mills equation, and the second equation describes a gluon condensate formed by coset fields. A flux tube solution describing longitudinal color electric fields stretched between quark and antiquark located at the ± infinities is obtained. It is shown that the dual Meissner effect appears in this solution: the electric field is pushed out from the gluon condensate.
Gotlibovych, Igor; Schmidutz, Tobias F.; Gaunt, Alexander L.; Navon, Nir; Smith, Robert P.; Hadzibabic, Zoran
2014-06-01
We study the properties of an atomic Bose-Einstein condensate produced in an optical-box potential, using high-resolution Bragg spectroscopy. For a range of box sizes, up to 70μm, we directly observe Heisenberg-limited momentum uncertainty of the condensed atoms. We measure the condensate interaction energy with a precision of kB×100 pK and study, both experimentally and numerically, the dynamics of its free expansion upon release from the box potential. All our measurements are in good agreement with theoretical expectations for a perfectly homogeneous condensate of spatial extent equal to the size of the box, which also establishes the uniformity of our optical-box system on a sub-nK energy scale.
Xiao, Fan; Williams, Rob; Lancaster, Tom; Landee, Christopher; Turnbull, Mark
A family of randomized two-dimensional quantum Heisenberg antiferromagnets (2DQHAF) (QuinH)2CuCl4xBr4 (1 - x) . 2 H2O (QuinH=quinolinium) have been synthesized and characterized. In such systems, the original interaction in the square lattice parent compound (x = 0) is partially replaced by a different exchange strength. Zero-field muon spin relaxation (ZF μ+SR) experiments have revealed that the magnetic long range ordering can be strongly suppressed by the introduction of the second interaction and the ordering temperature TN drops sharply as x increases. No 3D long range ordered state was observed in the compounds with x > 0 . 25 and the system stays disordered down to the lowest accessible temperature. The structure, magnetic properties and the TN - x phase diagram of the family will be presented.
International Nuclear Information System (INIS)
Manousakis, E.; Salvador, R.
1989-01-01
We study the spin-1/2 quantum ferromagnetic and antiferromagnetic Heisenberg model using Handscomb's Monte Carlo (MC) method on square lattices of various sizes. As the temperature is lowered the calculated correlation length in the antiferromagnetic case grows more rapidly than in the ferromagnetic case. We also obtain the correlation length in the leading order of the high-temperature series expansion which, at high temperatures, agrees very well with the MC results. The correlation length obtained from the MC calculation for the ferromagnetic and antiferromagnetic case is compared with existing theories. Taking the average value for the antiferromagnetic coupling between the values suggested by neutron- and Raman-scattering experiments done on La 2 CuO 4 , we compare our results for the correlation length with those observed by the neutron-scattering experiments. We find that our results for the correlation lengths away from the three-dimensional (3D) Neel temperature T/sub N/∼200 K are consistent with the experimental findings. In order to obtain agreement close to the Neel temperature, however, we need to introduce an interlayer coupling between the CuO 2 planes. The effect on a 3D coupling is only discussed in the framework of the quantum mechanical nonlinear σ model in three space dimensions. For the case of La 2 CuO 4 we find that close to T/sub N/ the σ model in 3+1 dimensions reduces to the classical 3D Heisenberg model whose critical properties are known and fit the neutron-scattering data for T∼T/sub N/
Roscher, Dietrich; Buessen, Finn Lasse; Scherer, Michael M.; Trebst, Simon; Diehl, Sebastian
2018-02-01
In frustrated magnetism, making a stringent connection between microscopic spin models and macroscopic properties of spin liquids remains an important challenge. A recent step towards this goal has been the development of the pseudofermion functional renormalization group approach (pf-FRG) which, building on a fermionic parton construction, enables the numerical detection of the onset of spin liquid states as temperature is lowered. In this work, focusing on the SU (N ) Heisenberg model at large N , we extend this approach in a way that allows us to directly enter the low-temperature spin liquid phase, and to probe its character. Our approach proceeds in momentum space, making it possible to keep the truncation minimalistic, while also avoiding the bias introduced by an explicit decoupling of the fermionic parton interactions into a given channel. We benchmark our findings against exact mean-field results in the large-N limit, and show that even without prior knowledge the pf-FRG approach identifies the correct mean-field decoupling channel. On a technical level, we introduce an alternative finite temperature regularization scheme that is necessitated to access the spin liquid ordered phase. In a companion paper [Buessen et al., Phys. Rev. B 97, 064415 (2018), 10.1103/PhysRevB.97.064415] we present a different set of modifications of the pf-FRG scheme that allow us to study SU (N ) Heisenberg models (using a real-space RG approach) for arbitrary values of N , albeit only up to the phase transition towards spin liquid physics.
Ravi Kumar, B.; Kaul, S. N.
2018-02-01
'Zero-field' linear ac magnetic susceptibility, χ1 (T), of the Cr75-xFe25+x (x = 0, 5) thin films with thickness, t, ranging from 980 to 10 nm has been measured at temperatures close to Tc , the temperature at which the ferromagnetic-paramagnetic phase transition occurs. An elaborate analysis of χ1 (T ⩾Tc) for the films with t ⩾ 40nm yields the temperature dependence of the effective critical exponent for susceptibility, γeff (T) , that is characteristic of the three-dimensional (3D) isotropic Heisenberg-to-3D isotropic dipolar crossover. In the asymptotic critical region (ACR), these thin-film samples behave as a 3D isotropic dipolar (ID) ferromagnet. As the film thickness reduces from t ≃ 980 nm to 40 nm, ACR narrows down while the temperature, Tdip , at which a dip in γeff (T) occurs and the temperature, TIH∗, that marks the onset of the 3D isotropic Heisenberg (IH) behavior, shift to lower temperatures. For a given t, the width of ACR as well as the characteristic temperatures Tdip and TIH∗ increase with decreasing (increasing) Fe (Cr) concentration. Consistent with these observations, the ratios involving nonlinear ac magnetic susceptibilities obey the generalized magnetic equation of state with 3D ID critical exponents and the value of Tc same as that determined from χ1 (T). A quantitative comparison between theory and experiment highlights certain limitations of the existing theories. The films with t ≲ 20 nm do not exhibit 3D IH-to-3D ID crossover. Instead, the critical behavior of Cr70Fe30 thin films with t = 21 nm and t = 11 nm is that of a 3D IH and 3D Ising ferromagnet, respectively. By contrast, a 3D Ising (spin glass) critical behavior is observed in the Cr75Fe25 thin film with t = 19 nm (t = 12 nm). Curie temperature, Tc , decreases with film thickness in accordance with the finite-size scaling.
Krajniak, Wiktor
2014-01-01
The purpose of this article is the analyses of discussion between Albert Einstein and Werner Heisenberg in the period 1925-1927. Their disputes, relating to the sources of scientific knowledge, its methods and the value of knowledge acquired in this way, are part of the characteristic for the European science discourse between rationalism and empirism. On the basis of some sources and literature on the subject, the epistemological positions of both scholars in the period were reconstructed. This episode, yet poorly known, is a unique example of scientific disputes, whose range covers a broad spectrum of methodological problems associated with the historical development of science. The conducted analysis sheds some light on the source of popularity of logical empirism in the first half of the 20th century. A particular emphasis is placed on the impact of the neopositivist ideas which reflect Heisenberg's research program, being the starting point for the Copenhagen interpretation of quantum mechanics. The main assumption of logical empirism, concerning acquisition of scientific knowledge only by means of empirical procedures and logical analysis of the language of science, in view of the voiced by Einstein arguments, bears little relationship with actual testing practices in the historical aspect of the development of science. The criticism of Heisenberg's program, carried out by Einstein, provided arguments for the main critics of the neopositivist ideal and contributed to the bankruptcy of the idea of logical empirism, thereby starting a period of critical rationalism prosperity, arising from criticism of neopositivism and alluding to Einstein's ideas.
Nataf, Pierre; Mila, Frédéric
2018-04-01
We develop an efficient method to perform density matrix renormalization group simulations of the SU(N ) Heisenberg chain with open boundary conditions taking full advantage of the SU(N ) symmetry of the problem. This method is an extension of the method previously developed for exact diagonalizations and relies on a systematic use of the basis of standard Young tableaux. Concentrating on the model with the fundamental representation at each site (i.e., one particle per site in the fermionic formulation), we have benchmarked our results for the ground-state energy up to N =8 and up to 420 sites by comparing them with Bethe ansatz results on open chains, for which we have derived and solved the Bethe ansatz equations. The agreement for the ground-state energy is excellent for SU(3) (12 digits). It decreases with N , but it is still satisfactory for N =8 (six digits). Central charges c are also extracted from the entanglement entropy using the Calabrese-Cardy formula and agree with the theoretical values expected from the SU (N) 1 Wess-Zumino-Witten conformal field theories.
International Nuclear Information System (INIS)
Wang, Pan; Tian, Bo; Jiang, Yan; Wang, Yu-Feng
2013-01-01
For describing the dynamics of alpha helical proteins with internal molecular excitations, nonlinear couplings between lattice vibrations and molecular excitations, and spin excitations in one-dimensional isotropic biquadratic Heisenberg ferromagnetic spin with the octupole–dipole interactions, we consider an inhomogeneous generalized fourth-order nonlinear Schrödinger equation. Based on the Ablowitz–Kaup–Newell–Segur system, infinitely many conservation laws for the equation are derived. Through the auxiliary function, bilinear forms and N-soliton solutions for the equation are obtained. Interactions of solitons are discussed by means of the asymptotic analysis. Effects of linear inhomogeneity on the interactions of solitons are also investigated graphically and analytically. Since the inhomogeneous coefficient of the equation h=α x+β, the soliton takes on the parabolic profile during the evolution. Soliton velocity is related to the parameter α, distance scale coefficient and biquadratic exchange coefficient, but has no relation with the parameter β. Soliton amplitude and width are only related to α. Soliton position is related to β
Hamid, Arian Zad
2016-12-01
We analytically investigate Multiple Quantum (MQ) NMR dynamics in a mixed-three-spin (1/2,1,1/2) system with XXX Heisenberg model at the front of an external homogeneous magnetic field B. A single-ion anisotropy property ζ is considered for the spin-1. The intensities dependence of MQ NMR coherences on their orders (zeroth and second orders) for two pairs of spins (1,1/2) and (1/2,1/2) of the favorite tripartite system are obtained. It is also investigated dynamics of the pairwise quantum entanglement for the bipartite (sub)systems (1,1/2) and (1/2,1/2) permanently coupled by, respectively, coupling constants J}1 and J}2, by means of concurrence and fidelity. Then, some straightforward comparisons are done between these quantities and the intensities of MQ NMR coherences and ultimately some interesting results are reported. We also show that the time evolution of MQ coherences based on the reduced density matrix of the pair spins (1,1/2) is closely connected with the dynamics of the pairwise entanglement. Finally, we prove that one can introduce MQ coherence of the zeroth order corresponds to the pair spins (1,1/2) as an entanglement witness at some special time intervals.
Energy Technology Data Exchange (ETDEWEB)
Utz, Yannic; Hammerath, Franziska; Nishimoto, Satoshi; Drechsler, Stefan-Ludwig; Hess, Christian; Buechner, Bernd; Grafe, Hans-Joachim [IFW Dresden (Germany); Beesetty, Neela Sekhar; Saint-Martin, Romuald; Revcolevschi, Alexandre [SP2M-ICMMO UMR-CNRS, Universite Paris-Sud (France)
2015-07-01
We present {sup 63}Cu NMR measurements on single crystals of Sr{sub 2}CuO{sub 3} doped with different amounts of nickel and compare them to numerical DMRG results. The parent compound contains copper-oxygen chains with S=1/2 on the copper site coupled by a large antiferromagnetic exchange coupling J ∼ 2000 K and is known to be a good realization of the 1D Heisenberg model. The measurements show that replacing only a few of the S=1/2 Cu ions with S=1 Ni has a major impact on the magnetic properties of the spin chain system. An unusual line broadening in the low temperature NMR spectra reveals the existence of an impurity-induced local alternating magnetization (LAM), and exponentially decaying spin-lattice relaxation rates T{sup -1}{sub 1} towards low temperatures indicate the opening of a spin gap similar to Ca-doped Sr{sub 2}CuO{sub 3}. While the T{sup -1}{sub 1} measurements could be explained by pure chain segmentation, as expected for a S=0 impurity, the spectra can only be understood by taking the nickel.
Evaluasi Sistem Informasi Penggajian Pada PT XYZ
Directory of Open Access Journals (Sweden)
Hari Setiabudi Husni
2010-06-01
Full Text Available The purpose of this study was to identify problems and weaknesses in the payroll information system, providing recommendations to reduce the risk of existing problems and produce audit reports for companies. Research method used is through literature study, interviews and observation. Audit method used is the method of auditing around the computer. Analysis was performed by analyzing the findings of problems, risks, and recommendations on the findings of the problem. After doing research, we conclude that there are still some weaknesses in management control and application control. But companies should be more focus on the weaknesses inherent limitations in controlling the application and control the output. Based on these findings, suggested that the company to rectify existing weaknesses and enhance control over payroll information system.
Modeling new XYZ states at JPAC
Energy Technology Data Exchange (ETDEWEB)
Pilloni, Alessandro [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-12-01
The observation of the unexpected XYZP resonances has challenged the usual heavy quarkonium framework. One of the most studied exotic states, the X(3872), happens to be copiously produced in high-energy hadron collisions. We discuss how this large prompt production cross-section, together with the comparison with light nuclei production data, disfavors a loosely-bound molecule interpretation, and calls for a new interpretation for the exotic hadron resonances. We also present the research of the Joint Physics Analysis Center in Hadron Spectroscopy.
Bimodal behavior of post-measured entropy and one-way quantum deficit for two-qubit X states
Yurischev, Mikhail A.
2018-01-01
A method for calculating the one-way quantum deficit is developed. It involves a careful study of post-measured entropy shapes. We discovered that in some regions of X-state space the post-measured entropy \\tilde{S} as a function of measurement angle θ \\in [0,π /2] exhibits a bimodal behavior inside the open interval (0,π /2), i.e., it has two interior extrema: one minimum and one maximum. Furthermore, cases are found when the interior minimum of such a bimodal function \\tilde{S}(θ ) is less than that one at the endpoint θ =0 or π /2. This leads to the formation of a boundary between the phases of one-way quantum deficit via finite jumps of optimal measured angle from the endpoint to the interior minimum. Phase diagram is built up for a two-parameter family of X states. The subregions with variable optimal measured angle are around 1% of the total region, with their relative linear sizes achieving 17.5%, and the fidelity between the states of those subregions can be reduced to F=0.968. In addition, a correction to the one-way deficit due to the interior minimum can achieve 2.3%. Such conditions are favorable to detect the subregions with variable optimal measured angle of one-way quantum deficit in an experiment.
Nakatsuji, S; Tonomura, H; Onuma, K; Nambu, Y; Sakai, O; Maeno, Y; Macaluso, R T; Chan, Julia Y
2007-10-12
Our single crystal study reveals that the single-layer S=2 triangular Heisenberg antiferromagnet FeGa2S4 forms a frozen spin-disordered state, similar to the S=1 isostructural magnet NiGa2S4. In this state, the magnetic specific heat C{M} is not only insensitive to the field, but shows a T2 dependence that scales to C{M} of NiGa2S4, suggesting the same underlying mechanism of the 2D coherent behavior. In contrast, the bilayer system Fe2Ga2S5 exhibits a 3D antiferromagnetic order.
Figueiredo, T. P.; Rocha, J. C. S.; Costa, B. V.
2017-12-01
Although the topological Berezinskii-Kosterlitz-Thouless transition was for the first time described by 40 years ago, it is still a matter of discussion. It has been used to explain several experiments in the most diverse physical systems. In contrast with the ordinary continuous phase transitions the BKT-transition does not break any symmetry. However, in some contexts it can easily be confused with other continuous transitions, in general due to an insufficient data analysis. The two-dimensional XY (or sometimes called planar rotator) spin model is the fruit fly model describing the BKT transition. As demonstrated by Bramwell and Holdsworth (1993) the finite-size effects are more important in two-dimensions than in others due to the logarithmic system size dependence of the properties of the system. Closely related is the anisotropic two dimensional Heisenberg model (AH). Although they have the same Hamiltonian the spin variable in the former has only two degrees of freedom while the AH has three. Many works treat the AH model as undergoing a transition in the same universality class as the XY model. However, its characterization as being in the BKT class of universality deserve some investigation. This paper has two goals. First, we describe an analytical evidence showing that the AH model is in the BKT class of universality. Second, we make an extensive simulation, using the numerical Replica Exchange Wang-Landau method that corroborate our analytical calculations. From our simulation we obtain the BKT transition temperature as TBKT = 0 . 6980(10) by monitoring the susceptibility, the two point correlation function and the helicity modulus. We discuss the misuse of the fourth order Binder's cumulant to locate the transition temperature. The specific heat is shown to have a non-critical behavior as expected in the BKT transition. An analysis of the two point correlation function at low temperature, C(r) ∝r - η(T), shows that the exponent, η, is consistent
Energy Technology Data Exchange (ETDEWEB)
Casado, A [Departamento de Fisica Aplicada III, Escuela Superior de Ingenieros, Universidad de Sevilla, 41092 Sevilla (Spain); Guerra, S [Centro Asociado de la Universidad Nacional de Educacion a Distancia de Las Palmas de Gran Canaria (Spain); Placido, J [Departamento de Fisica, Universidad de Las Palmas de Gran Canaria (Spain)], E-mail: acasado@us.es
2008-02-28
In this paper, the theory of parametric down-conversion in the Wigner representation is applied to Ekert's quantum cryptography protocol. We analyse the relation between two-photon entanglement and (non-secure) quantum key distribution within the Wigner framework in the Heisenberg picture. Experiments using two-qubit polarization entanglement generated in nonlinear crystals are analysed in this formalism, along with the effects of eavesdropping attacks in the case of projective measurements.
International Nuclear Information System (INIS)
Casado, A; Guerra, S; Placido, J
2008-01-01
In this paper, the theory of parametric down-conversion in the Wigner representation is applied to Ekert's quantum cryptography protocol. We analyse the relation between two-photon entanglement and (non-secure) quantum key distribution within the Wigner framework in the Heisenberg picture. Experiments using two-qubit polarization entanglement generated in nonlinear crystals are analysed in this formalism, along with the effects of eavesdropping attacks in the case of projective measurements
Quantum Simulation and Phase Diagram of the Transverse Field Ising Model with Three Atomic Spins
2010-05-25
for nine different combina- tions of J1 and J2 set by the beatnote detuning µ from Eq. 2. In Fig. 3 we present the results as a 3D plot of the FM or...be extended to simulate Heisenberg or XYZ spin models using additional laser beams [12]. This work is supported under Army Research Office (ARO) Award
International Nuclear Information System (INIS)
Chudnovsky, D.V.; Chudnovsky, G.V.
1981-01-01
We consider general expressions of factorized S-matrices with Abelian symmetry expressed in terms of theta-functions. These expressions arise from representations of the Heisenberg group. New examples of factorized S-matrices lead to a large class of completely integrable models of statistical mechanics which generalize the XYZ-model of the eight-vertex model. (orig.)
International Nuclear Information System (INIS)
Baranová, Lucia; Orendáčová, Alžbeta; Čižmár, Erik; Tarasenko, Róbert; Tkáč, Vladimír; Orendáč, Martin; Feher, Alexander
2016-01-01
Organo-metallic compounds Cu(en)(H 2 O) 2 SO 4 (en=C 2 H 8 N 2 ) and Cu(tn)Cl 2 (tn=C 3 H 10 N 2 ) representing S=1/2 quasi-two-dimensional Heisenberg antiferromagnets with an effective intra-layer exchange coupling J/k B ≈3 K, have been examined by specific heat measurements at temperatures down to nominally 50 mK and magnetic fields up to 14 T. A comparative analysis of magnetic specific heat in zero magnetic field revealed nearly identical contribution of short-range magnetic correlations and significant differences were observed at lowest temperatures. A phase transition to long-range order was observed in Cu(en)(H 2 O) 2 SO 4 at T C =0.9 K while hidden in Cu(tn)Cl 2 . A response of both compounds to the application of magnetic field has rather universal features characteristic for a field-induced Berezinskii–Kosterlitz–Thouless transition theoretically predicted for ideal two-dimensional magnets. - Highlights: • Magnetic specific heat of Cu(en)(H 2 O) 2 SO 4 (1) and Cu(tn)Cl 2 (2) was analysed. • In zero magnetic field, (1) and (2) behave as quasi-two-dimensional magnets. • We observed universal thermodynamic response of (1) and (2) to applied field. • Features of field-induced Berezinskii–Kosterlitz–Thouless transition were detected.
Energy Technology Data Exchange (ETDEWEB)
Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.c [Departamento de Fisica y Quimica, Universidad Nacional de Colombia-Sede Manizales, A.A. 127 Manizales (Colombia); Salazar-Enriquez, C.D.; Londono-Navarro, J.; Jurado, J.F. [Departamento de Fisica y Quimica, Universidad Nacional de Colombia-Sede Manizales, A.A. 127 Manizales (Colombia); Restrepo, J. [Grupo de Magnetismo y Simulacion, Instituto de Fisica. Universidad de Antioquia, A.A. 1226, Medellin (Colombia)
2011-06-15
This work presents a critical temperature study of La{sub 1-x}Ca{sub x}MnO{sub 3} manganites in bulk by means of Monte Carlo method thermal activated magnetic properties. The analysis was carried out for stoichiometries in the range of 0{<=}x{<=}1. The model is based on a three-dimensional classical Heisenberg-Hamiltonian involving the presence of Mn{sup 3+eg}, Mn{sup 3+eg'} and Mn{sup 4+} ions, and their nearest neighbor interaction. For this modeling, simple cubic lattice samples of size L{sup 3}, with L=6, 15 and 30 were used. The values of exchange parameters were determined by using LaMnO{sub 3} (x=0), La{sub 0.5}Ca{sub 0.5}MnO{sub 3} and CaMnO{sub 3} (x=1) phases. Relationships between exchange parameters and anisotropy constants for different hole densities were found. Results of transition temperatures for each phase showed good agreement with experimental reports, especially for L=30 and L{yields}{infinity}. - Research highlights: Stoichiometry influences the exchange interaction between magnetic ions. Charge and orbital ordering depend on the stoichiometry. LCMO magnetic phase diagram has a great variety of magnetic states.
International Nuclear Information System (INIS)
Belik, A.A.; Azuma, M.; Takano, M.
2004-01-01
Properties of Sr 2 Cu(PO 4 ) 2 and Ba 2 Cu(PO 4 ) 2 having [Cu(PO 4 ) 2 ] ∞ linear chains in their structures with Cu-O-P-O-Cu linkages were studied by magnetic susceptibility (T=2-400 K, H=100 Oe) and specific heat measurements (T=0.45-21 K). Magnetic susceptibility versus temperature curves, χ(T), showed broad maxima at T M =92 K for Sr 2 Cu(PO 4 ) 2 and T M =82 K for Ba 2 Cu(PO 4 ) 2 characteristic of quasi-one-dimensional systems. The χ(T) data were excellently fitted by the spin susceptibility curve for the uniform S=1/2 chain (plus temperature-independent and Curie-Weiss terms) with g=2.153(4) and J/k B =143.6(2) K for Sr 2 Cu(PO 4 ) 2 and g=2.073(4) and J/k B =132.16(9) K for Ba 2 Cu(PO 4 ) 2 (Hamiltonian H=JΣS i S i+1 ). The similar J/k B values were obtained from the specific heat data. No anomaly was observed on the specific heat from 0.45 to 21 K for both compounds indicating that the temperatures of long-range magnetic ordering, T N , were below 0.45 K. Sr 2 Cu(PO 4 ) 2 and Ba 2 Cu(PO 4 ) 2 are an excellent physical realization of the S=1/2 linear chain Heisenberg antiferromagnet with k B T N /J 2 CuO 3 (k B T N /J∼0.25%) and γ-LiV 2 O 5 (k B T N /J 2 Cu(PO 4 ) 2 and Ba 2 Cu(PO 4 ) 2 were stable in air up to 1280 and 1150 K, respectively
Shimahara, Hiroshi; Ito, Kazuhiro
2014-11-01
We examine a two-dimensional (2D) coupled antiferromagnetic (AF) Heisenberg model that consists of two subsystems: an isotropic S = 1/2 spin subsystem with strong AF exchange interactions (main system), and a uniaxial S = 5/2 spin subsystem with weak exchange interactions. This model is an example in which additional semiclassical degrees of freedom affect a quantum system; it also describes a possible stabilization mechanism of AF long-range order (LRO) in the 2D organic compound λ-(BETS)2FeCl4, where BETS stands for bis(ethylenedithio)tetraselenafulvalene. Previous experimental studies have revealed that 3d spins on FeCl4 anions passively follow the AF LRO of the π-electron system in the BETS layers, although the AF LRO is stabilized by the 3d spins themselves. To explain this paradoxical behavior, we examine a scenario in which the uniaxial anisotropy of the 3d spins stabilizes the AF LRO on an isotropic 2D π-spin system. We extend Green's function theory, called the Tyablikov approximation, to the present system, which describes spin-wave excitations and is consistent with the Mermin-Wagner theorem. It is shown that even extremely weak interactions with the uniaxial subsystem efficiently stabilize the AF LRO in the main system, even in the absence of AF exchange interactions in the uniaxial subsystem. The AF LRO is triggered by the uniaxial subsystem, but the sublattice magnetization remains smaller than that of the main system in the high-temperature region. These results are consistent with experimental data for λ-(BETS)2FeCl4 and λ-(BETS)2GaCl4; the latter does not have the 3d spins and does not exhibit the AF LRO.
Beterov, I. I.; Hamzina, G. N.; Yakshina, E. A.; Tretyakov, D. B.; Entin, V. M.; Ryabtsev, I. I.
2018-03-01
High-fidelity entangled Bell states are of great interest in quantum physics. Entanglement of ultracold neutral atoms in two spatially separated optical dipole traps is promising for implementation of quantum computing and quantum simulation and for investigation of Bell states of material objects. We propose a method to entangle two atoms via long-range Rydberg-Rydberg interaction. Alternative to previous approaches, based on Rydberg blockade, we consider radio-frequency-assisted Stark-tuned Förster resonances in Rb Rydberg atoms. To reduce the sensitivity of the fidelity of Bell states to the fluctuations of interatomic distance, we propose to use the double adiabatic passage across the radio-frequency-assisted Stark-tuned Förster resonances, which results in a deterministic phase shift of the collective two-atom state.
Analisis Dampak Penerapan IT Service Desk pada Bank XYZ
Directory of Open Access Journals (Sweden)
Ario Adi Prasetyo
2010-12-01
Full Text Available The purpose of this study is to identify the determinants of IT operational performance related to IT Service Desk. And to determine the consideration of implementing IT Service Desk in the company business processes. The population in this study is 1500 employees or users of the IT Service Desk service. By using the Slovin, 100 users were obtained in the sample. The variables in this study include success factors of IT Service Desk and Problem Management. Methods of data collection include using questionnaire s. Analysis of data is conducted using multivariate analysis of the factor analysis. The conclusions of this research is obtained from, among others, the factors of success of the IT Service Desk and Problem Management. There are 9 to 37 variables and indicators. From the research, it is found that there is a relationship between factors. And after the reduction process of 37 indicators four new factors was formed which consist of a quick solution factor, excellent IT Service Desk factor, focus support factor, and excellent staff factor. From all the new factors, quick solution is the most dominant factor.
Analisis Dampak Penerapan IT Service Desk pada Bank XYZ
Prasetyo, Ario Adi; Gaol, Ford Lumban
2010-01-01
The purpose of this study is to identify the determinants of IT operational performance related to IT Service Desk. And to determine the consideration of implementing IT Service Desk in the company business processes. The population in this study is 1500 employees or users of the IT Service Desk service. By using the Slovin, 100 users were obtained in the sample. The variables in this study include success factors of IT Service Desk and Problem Management. Methods of data collection include u...