A spectral route to determining chirality

DEFF Research Database (Denmark)

Pedersen, Jesper Goor; Mortensen, Asger

2009-01-01

We show how one-dimensional structured media can be used to measure chirality, via the spectral shift of the photonic band gap edges. Analytically, we show that a chiral contrast can, in some cases, be mapped unto an index contrast, thereby greatly simplifying the analysis of such structures. Using...... this mapping, we derive a first-order shift of the band gap edges with chirality. Potentially, this effect could be used for measuring enantiomeric excess....

DSAM lifetime measurements for the chiral pair in {sup 194}Tl

Energy Technology Data Exchange (ETDEWEB)

Masiteng, P.L.; Bvumbi, S.P. [National Research Foundation, iThemba LABS, PO Box 722, Somerset West (South Africa); University of the Western Cape, Private Bag X17, Bellville (South Africa); University of Johannesburg, PO Box 524, Auckland Park (South Africa); Pasternak, A.A. [A.F. Ioffe Physical-Technical Institute, St.-Petersburg (Russian Federation); Lawrie, E.A.; Shirinda, O.; Lawrie, J.J.; Bark, R.A.; Kheswa, N.Y.; Lieder, E.O.; Lieder, R.M.; Mullins, S.M.; Murray, S.H.T. [National Research Foundation, iThemba LABS, PO Box 722, Somerset West (South Africa); Lindsay, R. [University of the Western Cape, Private Bag X17, Bellville (South Africa); Madiba, T.E.; Sharpey-Schafer, J.F. [National Research Foundation, iThemba LABS, PO Box 722, Somerset West (South Africa); University of the Western Cape, Private Bag X17, Bellville (South Africa); Ndayishimye, J.; Papka, P. [National Research Foundation, iThemba LABS, PO Box 722, Somerset West (South Africa); University of Stellenbosch, Department of Physics, Private Bag X1, Matieland (South Africa); Ntshangase, S.S. [National Research Foundation, iThemba LABS, PO Box 722, Somerset West (South Africa); University of Cape Town, Department of Physics, Private Bag, Rondebosch (South Africa)

2016-02-15

Most important for the identification of chiral symmetry in atomic nuclei is to establish a pair of bands that are near-degenerate in energy, but also in B(M1) and B(E2) transition probabilities. Dedicated lifetime measurements were performed for four bands of {sup 194}Tl, including the pair of four-quasiparticle chiral bands with close near-degeneracy, considered as a prime candidate for best chiral symmetry pair. The lifetime measurements confirm the excellent near-degeneracy in this pair and indicate that a third band may be involved in the chiral symmetry scenario. (orig.)

Even- and Odd-Parity Charmed Meson Masses in Heavy Hadron Chiral Perturbation Theory

Energy Technology Data Exchange (ETDEWEB)

Thomas Mehen; Roxanne Springer

2005-03-01

We derive mass formulae for the ground state, J{sup P} = 0{sup -} and 1{sup -}, and first excited even-parity, J{sup P} = 0{sup +} and 1{sup +}, charmed mesons including one loop chiral corrections and {Omicron}(1/m{sub c}) counterterms in heavy hadron chiral perturbation theory. We show a variety of fits to the current data. We find that certain parameter relations in the parity doubling model are not renormalized at one loop, providing a natural explanation for the equality of the hyperfine splittings of ground state and excited doublets.

Extreme chirality in Swiss roll metamaterials

International Nuclear Information System (INIS)

Demetriadou, A; Pendry, J B

2009-01-01

The chiral Swiss roll metamaterial is a resonant, magnetic medium that exhibits a negative refractive band for one-wave polarization. Its unique structure facilitates huge chiral effects: a plane polarized wave propagating through this system can change its polarization by 90 deg. in less than a wavelength. Such chirality is at least 100 times greater than previous structures have achieved. In this paper, we discuss this extreme chiral behaviour with both numerical and analytical results.

Lateral shifting in one dimensional chiral photonic crystal

Energy Technology Data Exchange (ETDEWEB)

You Yuan, E-mail: yctcyouyuan@163.com [School of Physics and Electronics, Yancheng Teachers University, Yancheng, 224002 Jiangsu (China); Chen Changyuan [School of Physics and Electronics, Yancheng Teachers University, Yancheng, 224002 Jiangsu (China)

2012-07-01

We report the lateral shifts of the transmitted waves in a one dimensional chiral photonic crystal by using the stationary-phase approach. It is revealed that two kinds of lateral shifts are observed due to the existence of cross coupling in chiral materials, which is different from what has been observed in previous non-chiral photonic crystals. Unlike the chiral slab, the positions of lateral shift peaks are closely related to the band edges of band gap characteristics of periodic structure and lateral shifts can be positive as well as negative. Besides, the lateral shifts show a strong dependence on the chiral factor, which varies the lateral shift peaks in both magnitudes and positions. These features are desirable for future device applications.

Lateral shifting in one dimensional chiral photonic crystal

International Nuclear Information System (INIS)

You Yuan; Chen Changyuan

2012-01-01

We report the lateral shifts of the transmitted waves in a one dimensional chiral photonic crystal by using the stationary-phase approach. It is revealed that two kinds of lateral shifts are observed due to the existence of cross coupling in chiral materials, which is different from what has been observed in previous non-chiral photonic crystals. Unlike the chiral slab, the positions of lateral shift peaks are closely related to the band edges of band gap characteristics of periodic structure and lateral shifts can be positive as well as negative. Besides, the lateral shifts show a strong dependence on the chiral factor, which varies the lateral shift peaks in both magnitudes and positions. These features are desirable for future device applications.

Doublet method for very fast autocoding

Directory of Open Access Journals (Sweden)

Berman Jules J

2004-09-01

Full Text Available Abstract Background Autocoding (or automatic concept indexing occurs when a software program extracts terms contained within text and maps them to a standard list of concepts contained in a nomenclature. The purpose of autocoding is to provide a way of organizing large documents by the concepts represented in the text. Because textual data accumulates rapidly in biomedical institutions, the computational methods used to autocode text must be very fast. The purpose of this paper is to describe the doublet method, a new algorithm for very fast autocoding. Methods An autocoder was written that transforms plain-text into intercalated word doublets (e.g. "The ciliary body produces aqueous humor" becomes "The ciliary, ciliary body, body produces, produces aqueous, aqueous humor". Each doublet is checked against an index of doublets extracted from a standard nomenclature. Matching doublets are assigned a numeric code specific for each doublet found in the nomenclature. Text doublets that do not match the index of doublets extracted from the nomenclature are not part of valid nomenclature terms. Runs of matching doublets from text are concatenated and matched against nomenclature terms (also represented as runs of doublets. Results The doublet autocoder was compared for speed and performance against a previously published phrase autocoder. Both autocoders are Perl scripts, and both autocoders used an identical text (a 170+ Megabyte collection of abstracts collected through a PubMed search and the same nomenclature (neocl.xml, containing over 102,271 unique names of neoplasms. In side-by-side comparison on the same computer, the doublet method autocoder was 8.4 times faster than the phrase autocoder (211 seconds versus 1,776 seconds. The doublet method codes 0.8 Megabytes of text per second on a desktop computer with a 1.6 GHz processor. In addition, the doublet autocoder successfully matched terms that were missed by the phrase autocoder, while the

Decay patterns of multi-quasiparticle bands—a model independent test of chiral symmetry

International Nuclear Information System (INIS)

Lawrie, E A

2017-01-01

Nuclear chiral systems exhibit chiral symmetry bands, built on left-handed and right-handed angular momentum nucleon configurations. The experimental search for such chiral systems revealed a number of suitable candidates, however an unambiguous identification of nuclear chiral symmetry is still outstanding. In this work it is shown that the decay patterns of chiral bands built on multi-quasiparticle configurations are different from those involving different single-particle configurations. It is suggested to use the observed decay patterns of chiral candidates as a new model-independent test of chiral symmetry. (paper)

On integration over Fermi fields in chiral and supersymmetric theories

International Nuclear Information System (INIS)

Vainshtein, A.I.; Zakharov, V.I.

1982-01-01

Chiral and supersymmetric theories are considered which cannot be formulated directly in Euclidean space or regularized by means of massive fields in a manifestly gauge invariant fashion. In case of so called real representations a simple recipe is proposed which allows for unambiguous evaluation of the fermionic determinant circumventing the difficulties mentioned. As application of the general technique the effective fermionic interactions induced by instantons of small size within simplest chiral and supesymmetric theories are calculated (SU(2) as the gauge group and one doublet of Weyl spinors or a triplet of Majorana spinors, respectively). In the latter case the effective Lagrangian violates explicitly invariance under supersymmetric transformations on the fermionic and vector fields defined in standard way [ru

Theory of conductivity of chiral particles

International Nuclear Information System (INIS)

Kailasvuori, Janik; Šopík, Břetislav; Trushin, Maxim

2013-01-01

In this methodology focused paper we scrutinize the application of the band-coherent Boltzmann equation approach to calculating the conductivity of chiral particles. As the ideal testing ground we use the two-band kinetic Hamiltonian with an N-fold chiral twist that arises in a low-energy description of charge carriers in rhombohedrally stacked multilayer graphene. To understand the role of chirality in the conductivity of such particles we also consider the artificial model with the chiral winding number decoupled from the power of the dispersion. We first utilize the approximate but analytically solvable band-coherent Boltzmann approach including the ill-understood principal value terms that are a byproduct of several quantum many-body theory derivations of Boltzmann collision integrals. Further on, we employ the finite-size Kubo formula with the exact diagonalization of the total Hamiltonian perturbed by disorder. Finally, we compare several choices of Ansatz in the derivation of the Boltzmann equation according to the qualitative agreement between the Boltzmann and Kubo conductivities. We find that the best agreement can be reached in the approach where the principal value terms in the collision integral are absent. (paper)

Electroweak chiral Lagrangian from a natural topcolor-assisted technicolor model

International Nuclear Information System (INIS)

Lang Junyi; Jiang Shaozhou; Wang Qing

2009-01-01

Based on previous studies on computing coefficients of the electroweak chiral Lagrangian from C. T. Hill's schematic topcolor-assisted technicolor model, we generalize the calculation to K. Lane's prototype natural topcolor-assisted technicolor model. We find that typical features of the model are qualitatively similar to those of Hill's, but Lane's model prefers a smaller technicolor group and the Z ' mass must be smaller than 400 GeV. Furthermore, the S parameter is around the order of +1, mainly due to the existence of three doublets of techniquarks. We obtain the values for all coefficients of the electroweak chiral Lagrangian up to the order p 4 . Apart from large negative four-fermion coupling values, the extended technicolor impacts on the electroweak chiral Lagrangian coefficients are small, since the techniquark self energy, which determines these coefficients, in general receives almost no influence from the extended technicolor induced four-fermion interactions except for its large momentum tail.

A three-flavor chiral effective model with four baryonic multiplets within the mirror assignment

Energy Technology Data Exchange (ETDEWEB)

Olbrich, Lisa; Zetenyi, Miklos; Giacosa, Francesco; Rischke, Dirk H. [Institute for Theoretical Physics, Goethe University Frankfurt am Main (Germany)

2016-07-01

Chiral symmetry requires the existence of chiral partners in the hadronic mass spectrum. In this talk, we address the question which is the chiral partner of the nucleon. We employ a chirally symmetric linear sigma model, where hadrons and their chiral partners are treated on the same footing. We construct four spin-1/2 baryon multiplets from left- and right-handed quarks as well as left- and right-handed diquarks. Two of these multiplets transform in a ''mirror'' way, which allows for chirally invariant mass terms. We then embed these baryonic multiplets into the Lagrangian of the extended Linear Sigma Model, which features (pseudo)scalar and (axial-)vector mesons, as well as glueballs. Reducing the Lagrangian to the two-flavor case, we obtain four doublets of nucleonic states. These mix to produce the positive-parity nucleon N(939) and the Roper resonance N(1440), as well as the negative-parity resonances N(1535) and N(1650). We determine the parameters of the nucleonic part of the Lagrangian from a fit to masses and decay properties of these states. Studying the limit of vanishing quark condensate, we conclude that N(939) and N(1535), as well as N(1440) and N(1650) form pairs of chiral partners.

Origins of inert Higgs doublets

Directory of Open Access Journals (Sweden)

Thomas W. Kephart

2016-05-01

Full Text Available We consider beyond the standard model embedding of inert Higgs doublet fields. We argue that inert Higgs doublets can arise naturally in grand unified theories where the necessary associated Z2 symmetry can occur automatically. Several examples are discussed.

Can the ''doublet-triplet splitting'' problem be solved without doublet-triplet splitting?

International Nuclear Information System (INIS)

Dvali, G.R.

1992-03-01

We consider a new possible mechanism for the natural solution of the doublet-triplet splitting problem in SUSY GUTs. In contrast to the usually discussed scenarios, in our case the GUT symmetry breaking does not provide any splitting between the Higgs doublet and the triplet masses. The weak doublet and its colour triplet partner both remain light, but the triplet automatically occurs decoupled from the quark and lepton superfields and cannot induce proton decay. The advantage of the above scenarios is the absence at the GUT scale of the baryon number violating the tree level d = 5 and d = 6 operators via the colour-triple exchange. It is shown that in flipped SU(5) GUT they do not appear at any scale. In the SO(10) model, such operators can be induced after SUSY breaking but are strongly suppressed. (author). 22 refs, 2 figs

Higgs boson resonance parameters and the finite temperature phase transition in a chirally invariant Higgs-Yukawa model

Energy Technology Data Exchange (ETDEWEB)

Bulava, John; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Gerhold, Philip; Kallarackal, Jim; Nagy, Attila [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Humbolt-Univ. Berlin (Germany)

2011-12-15

We study a chirally invariant Higgs-Yukawa model regulated on a space-time lattice. We calculate Higgs boson resonance parameters and mass bounds for various values of the mass of the degenerate fermion doublet. Also, first results on the phase transition temperature are presented. In general, this model may be relevant for BSM scenarios with a heavy fourth generation of quarks. (orig.)

Shaping and characteristics of doublet plasmas in Doublet III

International Nuclear Information System (INIS)

Ohkawa, T.

1979-10-01

The shaping and plasma characteristics of doublet plasmas in Doublet III with high-Z limiters are described. Typical steady-state parameters at B/sub T/ = 24 kG are I/sub p/ = 1.5 MA, V/sub loop/ = 1.6 V, T/sub e/(O) = 1.0 keV, anti n/sub e/ = 4 x 10 13 cm -3 , Z/sub eff/ = 2, q(O) approx. 1 and tau /sub E//sup e/(O) = 20 msec. Electron energy confinement and maximum plasma density are in agreement with standard circular tokamak empirical scaling laws. Chromium and molybdenum appear to be the dominant high-Z plasma contaminants, with relative concentrations of approx. 10/sub -4/. The central power balance does not appear to be dominated by high-Z impurity radiation

The impact of reduction of doublet well spacing on the Net Present Value and the life time of fluvial Hot Sedimentary Aquifer doublets

DEFF Research Database (Denmark)

Willems, C. J. L.; Nick, H. M.; Goense, T.

2017-01-01

This paper evaluates the impact of reduction of doublet well spacing, below the current West Netherlands Basin standard of 1000 - 1500 m, on the Net Present Value (NPV) and the life time of fluvial Hot Sedimentary Aquifer (HSA) doublets. First, a sensitivity analysis is used to show the possible ...... the potential and risks of HSA doublets. This factor significantly affects doublet life time and net energy production of the doublet....

Continuum model for chiral induced spin selectivity in helical molecules

Energy Technology Data Exchange (ETDEWEB)

Medina, Ernesto [Centro de Física, Instituto Venezolano de Investigaciones Científicas, 21827, Caracas 1020 A (Venezuela, Bolivarian Republic of); Groupe de Physique Statistique, Institut Jean Lamour, Université de Lorraine, 54506 Vandoeuvre-les-Nancy Cedex (France); Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287 (United States); González-Arraga, Luis A. [IMDEA Nanoscience, Cantoblanco, 28049 Madrid (Spain); Finkelstein-Shapiro, Daniel; Mujica, Vladimiro [Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287 (United States); Berche, Bertrand [Centro de Física, Instituto Venezolano de Investigaciones Científicas, 21827, Caracas 1020 A (Venezuela, Bolivarian Republic of); Groupe de Physique Statistique, Institut Jean Lamour, Université de Lorraine, 54506 Vandoeuvre-les-Nancy Cedex (France)

2015-05-21

A minimal model is exactly solved for electron spin transport on a helix. Electron transport is assumed to be supported by well oriented p{sub z} type orbitals on base molecules forming a staircase of definite chirality. In a tight binding interpretation, the spin-orbit coupling (SOC) opens up an effective π{sub z} − π{sub z} coupling via interbase p{sub x,y} − p{sub z} hopping, introducing spin coupled transport. The resulting continuum model spectrum shows two Kramers doublet transport channels with a gap proportional to the SOC. Each doubly degenerate channel satisfies time reversal symmetry; nevertheless, a bias chooses a transport direction and thus selects for spin orientation. The model predicts (i) which spin orientation is selected depending on chirality and bias, (ii) changes in spin preference as a function of input Fermi level and (iii) back-scattering suppression protected by the SO gap. We compute the spin current with a definite helicity and find it to be proportional to the torsion of the chiral structure and the non-adiabatic Aharonov-Anandan phase. To describe room temperature transport, we assume that the total transmission is the result of a product of coherent steps.

Negative magnetoresistance without well-defined chirality in the Weyl semimetal TaP.

Science.gov (United States)

Arnold, Frank; Shekhar, Chandra; Wu, Shu-Chun; Sun, Yan; Dos Reis, Ricardo Donizeth; Kumar, Nitesh; Naumann, Marcel; Ajeesh, Mukkattu O; Schmidt, Marcus; Grushin, Adolfo G; Bardarson, Jens H; Baenitz, Michael; Sokolov, Dmitry; Borrmann, Horst; Nicklas, Michael; Felser, Claudia; Hassinger, Elena; Yan, Binghai

2016-05-17

Weyl semimetals (WSMs) are topological quantum states wherein the electronic bands disperse linearly around pairs of nodes with fixed chirality, the Weyl points. In WSMs, nonorthogonal electric and magnetic fields induce an exotic phenomenon known as the chiral anomaly, resulting in an unconventional negative longitudinal magnetoresistance, the chiral-magnetic effect. However, it remains an open question to which extent this effect survives when chirality is not well-defined. Here, we establish the detailed Fermi-surface topology of the recently identified WSM TaP via combined angle-resolved quantum-oscillation spectra and band-structure calculations. The Fermi surface forms banana-shaped electron and hole pockets surrounding pairs of Weyl points. Although this means that chirality is ill-defined in TaP, we observe a large negative longitudinal magnetoresistance. We show that the magnetoresistance can be affected by a magnetic field-induced inhomogeneous current distribution inside the sample.

Semialigned two Higgs doublet model

Science.gov (United States)

Haba, Naoyuki; Umeeda, Hiroyuki; Yamada, Toshifumi

2018-02-01

In the left-right symmetric model based on S U (2 )L×S U (2 )R×U (1 )B -L gauge symmetry, there appear heavy neutral scalar particles mediating quark flavor changing neutral currents (FCNCs) at tree level. We consider a situation where such FCNCs give the only sign of the left-right model while WR gauge boson is decoupled, and name it "semialigned two Higgs doublet model" because the model resembles a two Higgs doublet model with mildly aligned Yukawa couplings to quarks. We predict a correlation among processes induced by quark FCNCs in the model, and argue that future precise calculation of meson-antimeson mixings and C P violation therein may hint at the semialigned two Higgs doublet model and the left-right model behind it.

On doublet composite schemes of leptons and quarks

International Nuclear Information System (INIS)

Pirogov, Yu.F.

1981-01-01

All simplest doublet composite schemes are classified. Four different doublet schemes are shown to be available. A new scheme with charge doublet Q=(2/3, -1/3) rather advantageous as compared with the previous ones is being considered. Some difficulties in interpreting the colour as an effective symmetry are pointed out [ru

Molecular architecture of axonemal microtubule doublets revealedby cryo-electron tomography

Energy Technology Data Exchange (ETDEWEB)

Sui, Haixin; Downing, Kenneth H.

2006-05-22

The axoneme, which forms the core of eukaryotic flagella and cilia, is one of the largest macromolecular machines with a structure that is largely conserved from protists to mammals. Microtubule doublets are structural components of axonemes containing a number of proteins besides tubulin, and are usually found in arrays of nine doublets arranged around two singlet microtubules. Coordinated sliding of adjacent doublets, which involves a host of other proteins in the axoneme, produces periodic beating movements of the axoneme. We have obtained a 3D density map of intact microtubule doublets using cryo-electron tomography and image averaging. Our map, with a resolution of about 3 nm, provides insights into locations of particular proteins within the doublets and the structural features of the doublets that define their mechanical properties. We identify likely candidates for several of these non-tubulin components of the doublets. This work offers novel insight on how tubulin protofilaments and accessory proteins attach together to form the doublets and provides a structural basis for understanding doublet function in axonemes.

Oxaliplatin-Based Doublets Versus Cisplatin or Carboplatin-Based Doublets in the First-Line Treatment of Advanced Nonsmall Cell Lung Cancer.

Science.gov (United States)

Yu, Jing; Xiao, Jing; Yang, Yifan; Cao, Bangwei

2015-07-01

The efficacy and toxicity of oxaliplatin-based versus carboplatin/cisplatin-based doublets in patients with previously untreated nonsmall cell lung cancer (NSCLC) have been compared.We searched published randomized controlled trials of oxaliplatin-based or carboplatin/cisplatin-based medications for NSCLC. A fixed effect model was used to analyze outcomes which were expressed as the hazard ratio for overall survival (OS) and time-to-progression (TTP), relative risk, overall response rate (ORR), disease control rate (DCR), 1-year survival, and the odds ratios for toxicity were pooled.Eight studies involving 1047 patients were included. ORR tended to favor carboplatin/cisplatin but the effect was not significantly different compared with oxaliplatin doublets (P = 0.05). The effects of OS, TTP, DCR, and 1-year survival between the 2 regimens were comparable. Oxaliplatin doublets caused less grade 3/4 leukocytopenia and neutropenia. Grades 3 to 4 nonhematological toxicities and grades 3 to 4 hematological toxicities showed little difference between oxaliplatin doublets and carboplatin/cisplatin doublets.Meta-analysis shows that the efficacy of oxaliplatin doublets is similar to that of other currently used platinum doublets. The lack of significant differences in the statistic analysis does not preclude genuine differences in clinical efficacy, because higher diversities between the studies covered differences between the 2 groups in each study. Oxaliplatin combined with a third-generation agent should be considered for use as alternative chemotherapy in patients who cannot tolerate conventional platinum-based regimens because the toxicity profile is much more favorable.

Chiral zero energy modes in two-dimensional disordered Dirac semimetals

Science.gov (United States)

Liu, Lei; Yu, Yan; Wu, Hai-Bin; Zhang, Yan-Yang; Liu, Jian-Jun; Li, Shu-Shen

2018-04-01

The vacancy-induced chiral zero energy modes (CZEMs) of chiral-unitary-class (AIII) and chiral-symplectic-class (CII) two-dimensional (2 D ) disordered Dirac semimetals realized on a square bipartite lattice are investigated numerically by using the Kubo-Greenwood formula with the kernel polynomial method. The results show that, for both systems, the CZEMs exhibit the critical delocalization. The CZEM conductivity remains a robust constant (i.e., σ CZEM≈1.05 e2/h ), which is insensitive to the sample sizes, the vacancy concentrations, and the numbers of moments of Chebyshev polynomials, i.e., the dephasing strength. For both kinds of chiral systems, the CZEM conductivities are almost identical. However, they are not equal to that of graphene (i.e., 4 e2/π h ), which belongs to the chiral orthogonal class (BDI) semimetal on a 2 D hexagonal bipartite lattice. In addition, for the case that the vacancy concentrations are different in the two sublattices, the CZEM conductivity vanishes, and thus both systems exhibit localization at the Dirac point. Moreover, a band gap and a mobility gap open around zero energy. The widths of the energy gaps and mobility gaps are increasing with larger vacancy concentration difference. The width of the mobility gap is greater than that of the band gap, and a δ -function-like peak of density of states emerges at the Dirac point within the band gap, implying the existence of numerous localized states.

Chirality, Metallicity, and Transition Dependent Asymmetries in Resonance Raman Excitation Profiles of Chirality-Enriched Carbon Nanotubes

Science.gov (United States)

Doorn, Stephen; Duque, Juan; Telg, Hagen; Haroz, Erik; Tu, Xiaomin; Zheng, Ming

2014-03-01

Access to carbon nanotube samples enriched in single chiralities allows the observation of new photophysical behaviors obscured or difficult to demonstrate in mixed-chirality ensembles. Recent examples include the observation of strongly asymmetric G-band excitation profiles resulting from non-Condon effects1 and the unambiguous demonstration of Raman interference effects.2 We present here our most recent results demonstrating the generality of the non-Condon behavior to include metallic species (specifically several armchair chiralities). Additionally, the Eii dependence in non-Condon behavior with excitations from E11 thru E44 for both RBM and G modes will be discussed. 1. J.G. Duque, et. al., ACS Nano, 5, 5233 (2011). 2. J.G. Duque, et. al., Phys. Rev. Lett. 108, 117404 (2012).

A New Linearization Technique Using Multi-sinh Doublet

Directory of Open Access Journals (Sweden)

CEHAN, V.

2009-06-01

Full Text Available In this paper a new linearization technique using multi-sinh doublet, implemented with a second generation current conveyor is presented. This new linearization technique is compared with the one based on multi-tanh doublets with linearization series connected diodes on the branches. The comparative study of the two linearization techniques is carried out using both dynamic range analysis, expressed by linearity error and the THD value calculation of output current, and the noise behavior of the two analyzed doublets. For the multi-sinh linearization technique proposed in the paper a method which assures the increase of the dynamic range, keeping the transconductance value constant is presented. This is done by using two design parameters: the number of series connected diodes N, which specifies the desired linear operating range and the k emitters areas ratio of the input stage transistors, which establishes the transconductance value. In the paper is also shown that if the transconductances of the two analyzed doublets are identical, and for the same values of N and k parameters, respectively, the current consumption of the multi-sinh doublet is always smaller than for the multi-tanh doublet.

Higgs properties in the Stealth Doublet Model

Directory of Open Access Journals (Sweden)

Wouda Glenn

2013-11-01

Full Text Available I present a model with two scalar doublets and a softly broken ℤ2 symmetry, where only one of the doublets gets a vacuum expectation value and couples to fermions at tree-level. The softly broken ℤ2 symmetry leads to interesting phenomenology such as mixing between the two doublets and a charged scalar H± which can be light and dominantly decays into Hγ. The model can also naturally reproduce an enhanced γγ signal of the newly observed Higgs boson at the LHC with mass 125 GeV.

2HDM portal for Singlet-Doublet Dark Matter

OpenAIRE

Arcadi, Giorgio

2018-01-01

We present an extensive analysis of a model in which the (Majorana) Dark Matter candidate is a mixture between a SU(2) singlet and two SU(2) doublets. This kind of setup takes the name of singlet-doublet model. We will investigate in detail an extension of this model in which the Dark Matter sector interactions with a 2-doublet Higgs sector enforcing the complementarity between Dark Matter phenomenology and searches of extra Higgs bosons.

Symmetries for SM Alignment in multi-Higgs Doublet Models

CERN Document Server

Pilaftsis, Apostolos

2016-01-01

We derive the complete set of maximal symmetries for Standard Model (SM) alignment that may occur in the tree-level scalar potential of multi-Higgs Doublet Models, with $n > 2$ Higgs doublets. Our results generalize the symmetries of SM alignment, without decoupling of large mass scales or fine-tuning, previously obtained in the context of two-Higgs Doublet Models.

CP violation conditions in N-Higgs-doublet potentials

International Nuclear Information System (INIS)

Nishi, C. C.

2006-01-01

Conditions for CP violation in the scalar potential sector of general N-Higgs-doublet models are analyzed from a group theoretical perspective. For the simplest two-Higgs-doublet model potential, a minimum set of conditions for explicit and spontaneous CP violation is presented. The conditions can be given a clear geometrical interpretation in terms of quantities in the adjoint representation of the basis transformation group for the two doublets. Such conditions depend on CP-odd pseudoscalar invariants. When the potential is CP invariant, the explicit procedure to reach the real CP-basis and the explicit CP transformation can also be obtained. The procedure to find the real basis and the conditions for CP violation are then extended to general N-Higgs-doublet model potentials. The analysis becomes more involved and only a formal procedure to reach the real basis is found. Necessary conditions for CP invariance can still be formulated in terms of group invariants: the CP-odd generalized pseudoscalars. The problem can be completely solved for three Higgs-doublets

Finite density two color chiral perturbation theory revisited

Science.gov (United States)

Adhikari, Prabal; Beleznay, Soma B.; Mannarelli, Massimo

2018-06-01

We revisit two-color, two-flavor chiral perturbation theory at finite isospin and baryon density. We investigate the phase diagram obtained varying the isospin and the baryon chemical potentials, focusing on the phase transition occurring when the two chemical potentials are equal and exceed the pion mass (which is degenerate with the diquark mass). In this case, there is a change in the order parameter of the theory that does not lend itself to the standard picture of first order transitions. We explore this phase transition both within a Ginzburg-Landau framework valid in a limited parameter space and then by inspecting the full chiral Lagrangian in all the accessible parameter space. Across the phase transition between the two broken phases the order parameter becomes an SU(2) doublet, with the ground state fixing the expectation value of the sum of the magnitude squared of the pion and the diquark fields. Furthermore, we find that the Lagrangian at equal chemical potentials is invariant under global SU(2) transformations and construct the effective Lagrangian of the three Goldstone degrees of freedom by integrating out the radial fluctuations.

Vacuum stability in neutrinophilic Higgs doublet model

International Nuclear Information System (INIS)

Haba, Naoyuki; Horita, Tomohiro

2011-01-01

A neutrinophilic Higgs model has tiny vacuum expectation value (VEV), which can naturally explain tiny masses of neutrinos. There is a large energy scale hierarchy between a VEV of the neutrinophilic Higgs doublet and that of usual standard model-like Higgs doublet. In this Letter we at first analyze vacuum structures of Higgs potential in both supersymmetry (SUSY) and non-SUSY neutrinophilic Higgs models, and next investigate a stability of this VEV hierarchy against radiative corrections. We will show that the VEV hierarchy is stable against radiative corrections in both Dirac neutrino and Majorana neutrino scenarios in both SUSY and non-SUSY neutrinophilic Higgs doublet models.

Omnidirectional narrow optical filters for circularly polarized light in a nanocomposite structurally chiral medium.

Science.gov (United States)

Avendaño, Carlos G; Palomares, Laura O

2018-04-20

We consider the propagation of electromagnetic waves throughout a nanocomposite structurally chiral medium consisting of metallic nanoballs randomly dispersed in a structurally chiral material whose dielectric properties can be represented by a resonant effective uniaxial tensor. It is found that an omnidirectional narrow pass band and two omnidirectional narrow band gaps are created in the blue optical spectrum for right and left circularly polarized light, as well as narrow reflection bands for right circularly polarized light that can be controlled by varying the light incidence angle and the filling fraction of metallic inclusions.

Chiral plaquette polaron theory of cuprate superconductivity

Science.gov (United States)

Tahir-Kheli, Jamil; Goddard, William A., III

2007-07-01

Ab initio density functional calculations on explicitly doped La2-xSrxCuO4 find that doping creates localized holes in out-of-plane orbitals. A model for cuprate superconductivity is developed based on the assumption that doping leads to the formation of holes on a four-site Cu plaquette composed of the out-of-plane A1 orbitals apical Opz , planar Cud3z2-r2 , and planar Opσ . This is in contrast to the assumption of hole doping into planar Cudx2-y2 and Opσ orbitals as in the t-J model. Allowing these holes to interact with the d9 spin background leads to chiral polarons with either a clockwise or anticlockwise charge current. When the polaron plaquettes percolate through the crystal at x≈0.05 for La2-xSrxCuO4 , a Cudx2-y2 and planar Opσ band is formed. The computed percolation doping of x≈0.05 equals the observed transition to the “metallic” and superconducting phase for La2-xSrxCuO4 . Spin exchange Coulomb repulsion with chiral polarons leads to d -wave superconducting pairing. The equivalent of the Debye energy in phonon superconductivity is the maximum energy separation between a chiral polaron and its time-reversed partner. This energy separation is on the order of the antiferromagnetic spin coupling energy, Jdd˜0.1eV , suggesting a higher critical temperature. An additive skew-scattering contribution to the Hall effect is induced by chiral polarons and leads to a temperature dependent Hall effect that fits the measured values for La2-xSrxCuO4 . The integrated imaginary susceptibility, observed by neutron spin scattering, satisfies ω/T scaling due to chirality and spin-flip scattering of polarons along with a uniform distribution of polaron energy splittings. The derived functional form is compatible with experiments. The static spin structure factor for chiral spin coupling of the polarons to the undoped antiferromagnetic Cud9 spins is computed for classical spins on large two-dimensional lattices and is found to be incommensurate with a

Structural insights into microtubule doublet interactions inaxonemes

Energy Technology Data Exchange (ETDEWEB)

Downing, Kenneth H.; Sui, Haixin

2007-06-06

Coordinated sliding of microtubule doublets, driven by dynein motors, produces periodic beating of the axoneme. Recent structural studies of the axoneme have used cryo-electron tomography to reveal new details of the interactions among some of the multitude of proteins that form the axoneme and regulate its movement. Connections among the several sets of dyneins, in particular, suggest ways in which their actions may be coordinated. Study of the molecular architecture of isolated doublets has provided a structural basis for understanding the doublet's mechanical properties that are related to the bending of the axoneme, and has also offered insight into its potential role in the mechanism of dynein activity regulation.

Model for particle masses, flavor mixing, and CP violation, based on spontaneously broken discrete chiral symmetry as the origin of families

International Nuclear Information System (INIS)

Adler, S.L.

1999-01-01

We construct extensions of the standard model based on the hypothesis that Higgs bosons also exhibit a family structure and that the flavor weak eigenstates in the three families are distinguished by a discrete Z 6 chiral symmetry that is spontaneously broken by the Higgs sector. We study in detail at the tree level models with three Higgs doublets and with six Higgs doublets comprising two weakly coupled sets of three. In a leading approximation of S 3 cyclic permutation symmetry the three-Higgs-doublet model gives a open-quotes democraticclose quotes mass matrix of rank 1, while the six-Higgs-doublet model gives either a rank-1 mass matrix or, in the case when it spontaneously violates CP, a rank-2 mass matrix corresponding to nonzero second family masses. In both models, the CKM matrix is exactly unity in the leading approximation. Allowing small explicit violations of cyclic permutation symmetry generates small first family masses in the six-Higgs-doublet model, and first and second family masses in the three-Higgs-doublet model, and gives a nontrivial CKM matrix in which the mixings of the first and second family quarks are naturally larger than mixings involving the third family. Complete numerical fits are given for both models, flavor-changing neutral current constraints are discussed in detail, and the issues of unification of couplings and neutrino masses are addressed. On a technical level, our analysis uses the theory of circulant and retrocirculant matrices, the relevant parts of which are reviewed. copyright 1998 The American Physical Society

Three-nucleon scattering by using chiral perturbation theory potential

International Nuclear Information System (INIS)

Kamata, Hiroyuki

2003-01-01

Three-nucleon scattering problems are studied by using two-nucleon and three-nucleon potentials derived from chiral perturbation theory. The three-nucleon term is shown to appear in the effective potential of the rank of next-to-next-to-leading order (NNLO). New three-nucleon forces are taken into consideration in addition to the conventional Fujita-Miyazawa (FM) type three-nucleon potential. Two-nucleon potential of the chiral perturbation theory is as precise as the conventional ones in low energy region. The FM type three-nucleon force which explains Sagara discrepancy in high energy region is introduced automatically. Concerning the Ay puzzle, the results seems to behave as if the puzzle has been solved at the level of NLO, but at the NNLO (without three-nucleon force) level the result is similar to the cases of conventional potential indicating the need of three-nucleon force. In contrast to the FM type three-nucleon force, five free parameters exist in the new D and E type three-nucleon forces introduced by the NNLO, but they are reduced to two independent parameters by antisymmetrization, which are found to be sensitive to the coupling energy of tritons and to the nd scattering length (spin doublet state). Parameters determined from them cannot give satisfactory answer to the A y puzzle. It seems, however, too hasty to conclude that A y puzzle cannot be solved by the chiral perturbation theory. (S. Funahashi)

Chiral near-fields around chiral dolmen nanostructure

International Nuclear Information System (INIS)

Fu, Tong; Wang, Tiankun; Chen, Yuyan; Wang, Yongkai; Qu, Yu; Zhang, Zhongyue

2017-01-01

Discriminating the handedness of the chiral molecule is of great importance in the field of pharmacology and biomedicine. Enhancing the chiral near-field is one way to increase the chiral signal of chiral molecules. In this paper, the chiral dolmen nanostructure (CDN) is proposed to enhance the chiral near-field. Numerical results show that the CDN can increase the optical chirality of the near-field by almost two orders of magnitude compared to that of a circularly polarized incident wave. In addition, the optical chirality of the near-field of the bonding mode is enhanced more than that of the antibonding mode. These results provide an effective method for tailoring the chiral near-field for biophotonics sensors. (paper)

On Charge Conjugation, Chirality and Helicity of the Dirac and Majorana Equation for Massive Leptons

Directory of Open Access Journals (Sweden)

Eckart Marsch

2015-04-01

Full Text Available We revisit the charge-conjugation operation for the Dirac equation in its chiral representation. A new decomposition of the Dirac spinor field is suggested and achieved by means of projection operators based on charge conjugation, which is discussed here in a non-standard way. Thus, two separate two-component Majorana-type field equations for the eigenfields of the charge-conjugation operator are obtained. The corresponding free fields are entirely separated without a gauge field, but remain mixed and coupled together through an electromagnetic field term. For fermions that are charged and, thus, subjected to the gauge field of electrodynamics, these two Majorana fields can be reassembled into a doublet, which is equivalent to a standard four-component Dirac spinor field. In this way, the Dirac equation is retained in a new guise, which is fully equivalent to that equation in its chiral form.

Mechanical separation of chiral dipoles by chiral light

International Nuclear Information System (INIS)

Canaguier-Durand, Antoine; Hutchison, James A; Genet, Cyriaque; Ebbesen, Thomas W

2013-01-01

We calculate optical forces and torques exerted on a chiral dipole by chiral light fields and reveal genuine chiral forces in combining the chiral contents of both light field and dipolar matter. Here, the optical chirality is characterized in a general way through the definition of optical chirality density and chirality flow. We show, in particular, that both terms have mechanical effects associated, respectively, with reactive and dissipative components of the chiral forces. Remarkably, these chiral force components are directly related to standard observables: optical rotation for the reactive component and circular dichroism for the dissipative one. As a consequence, the resulting forces and torques are dependent on the enantiomeric form of the chiral dipole. This suggests promising strategies for using chiral light forces to mechanically separate chiral objects according to their enantiomeric form. (paper)

Competitive chiral induction in a 2D molecular assembly: Intrinsic chirality versus coadsorber-induced chirality.

Science.gov (United States)

Chen, Ting; Li, Shu-Ying; Wang, Dong; Wan, Li-Jun

2017-11-01

Noncovalently introducing stereogenic information is a promising approach to embed chirality in achiral molecular systems. However, the interplay of the noncovalently introduced chirality with the intrinsic chirality of molecules or molecular aggregations has rarely been addressed. We report a competitive chiral expression of the noncovalent interaction-mediated chirality induction and the intrinsic stereogenic center-controlled chirality induction in a two-dimensional (2D) molecular assembly at the liquid/solid interface. Two enantiomorphous honeycomb networks are formed by the coassembly of an achiral 5-(benzyloxy)isophthalic acid (BIC) derivative and 1-octanol at the liquid/solid interface. The preferential formation of the globally homochiral assembly can be achieved either by using the chiral analog of 1-octanol, ( S )-6-methyl-1-octanol, as a chiral coadsorber to induce chirality to the BIC assembly via noncovalent hydrogen bonding or by covalently linking a chiral center in the side chain of BIC. Both the chiral coadsorber and the intrinsically chiral BIC derivative can act as a chiral seeds to induce a preferred handedness in the assembly of the achiral BIC derivatives. Furthermore, the noncovalent interaction-mediated chirality induction can restrain or even overrule the manifestation of the intrinsic chirality of the BIC molecule and dominate the handedness of the 2D molecular coassembly. This study provides insight into the interplay of intrinsically chiral centers and external chiral coadsorbers in the chiral induction, transfer, and amplification processes of 2D molecular assembly.

Chiral Gold Nanoclusters: Atomic Level Origins of Chirality.

Science.gov (United States)

Zeng, Chenjie; Jin, Rongchao

2017-08-04

Chiral nanomaterials have received wide interest in many areas, but the exact origin of chirality at the atomic level remains elusive in many cases. With recent significant progress in atomically precise gold nanoclusters (e.g., thiolate-protected Au n (SR) m ), several origins of chirality have been unveiled based upon atomic structures determined by using single-crystal X-ray crystallography. The reported chiral Au n (SR) m structures explicitly reveal a predominant origin of chirality that arises from the Au-S chiral patterns at the metal-ligand interface, as opposed to the chiral arrangement of metal atoms in the inner core (i.e. kernel). In addition, chirality can also be introduced by a chiral ligand, manifested in the circular dichroism response from metal-based electronic transitions other than the ligand's own transition(s). Lastly, the chiral arrangement of carbon tails of the ligands has also been discovered in a very recent work on chiral Au 133 (SR) 52 and Au 246 (SR) 80 nanoclusters. Overall, the origins of chirality discovered in Au n (SR) m nanoclusters may provide models for the understanding of chirality origins in other types of nanomaterials and also constitute the basis for the development of various applications of chiral nanoparticles. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chiral symmetry and chiral-symmetry breaking

International Nuclear Information System (INIS)

Peskin, M.E.

1982-12-01

These lectures concern the dynamics of fermions in strong interaction with gauge fields. Systems of fermions coupled by gauge forces have a very rich structure of global symmetries, which are called chiral symmetries. These lectures will focus on the realization of chiral symmetries and the causes and consequences of thier spontaneous breaking. A brief introduction to the basic formalism and concepts of chiral symmetry breaking is given, then some explicit calculations of chiral symmetry breaking in gauge theories are given, treating first parity-invariant and then chiral models. These calculations are meant to be illustrative rather than accurate; they make use of unjustified mathematical approximations which serve to make the physics more clear. Some formal constraints on chiral symmetry breaking are discussed which illuminate and extend the results of our more explicit analysis. Finally, a brief review of the phenomenological theory of chiral symmetry breaking is presented, and some applications of this theory to problems in weak-interaction physics are discussed

Gelation induced supramolecular chirality: chirality transfer, amplification and application.

Science.gov (United States)

Duan, Pengfei; Cao, Hai; Zhang, Li; Liu, Minghua

2014-08-14

Supramolecular chirality defines chirality at the supramolecular level, and is generated from the spatial arrangement of component molecules assembling through non-covalent interactions such as hydrogen bonding, van der Waals interactions, π-π stacking, hydrophobic interactions and so on. During the formation of low molecular weight gels (LMWGs), one kind of fascinating soft material, one frequently encounters the phenomenon of chirality as well as chiral nanostructures, either from chiral gelators or even achiral gelators. A view of gelation-induced supramolecular chirality will be very helpful to understand the self-assembly process of the gelator molecules as well as the chiral structures, the regulation of the chirality in the gels and the development of the "smart" chiral materials such as chiroptical devices, catalysts and chiral sensors. It necessitates fundamental understanding of chirality transfer and amplification in these supramolecular systems. In this review, recent progress in gelation-induced supramolecular chirality is discussed.

The impact of reduction of doublet well spacing on the Net Present Value and the life time of fluvial Hot Sedimentary Aquifer doublets

NARCIS (Netherlands)

Willems, C.J.L.; Maghami Nick, Hamidreza M.; Bruhn, D.F.

This paper evaluates the impact of reduction of doublet well spacing, below the current West Netherlands Basin standard of 1000 to 1500 m, on the Net Present Value (NPV) and the life time of fluvial Hot Sedimentary Aquifer (HSA) doublets. First, a sensitivity analysis is used to show the possible

Doublet Tracer Testing in Klamath Falls, Oregon

Energy Technology Data Exchange (ETDEWEB)

Gudmundsson, J S; Johnson, S E; Horne, R N; Jackson, P B [Pet. Eng. Dept., Stanford University; Culver, G G [Geo-Heat Center, Oregon Institute of Technology, Klamath Falls, OR

0000-12-30

A tracer test was carried out in a geothermal doublet system to study the injection behavior of a developed reservoir known to be fractured. The doublet produces about 320 gpm of 160 degrees Fahrenheit water that is used for space heating and then injected; the wells are spaced 250 ft apart. Tracer breakthrough was observed in 2 hours and 45 minutes in the production well, indicating fracture flow. However, the tracer concentrations were low and indicated porous media flow; the tracers mixed with a reservoir volume much larger than a fracture.

Doublet Tracer Testing in Klamath Falls, Oregon

Energy Technology Data Exchange (ETDEWEB)

Gudmundsson, J.S.; Johnson, S.E.; Horne, R.N.; Jackson, P. B. [Pet. Eng. Dept., Stanford University; Culver, G.G. [Geo-Heat Center, Oregon Institute of Technology, Klamath Falls, OR

0001-01-01

A tracer test was carried out in a geothermal doublet system to study the injection behavior of a developed reservoir known to be fractured. The doublet produces about 320 gpm of 160 degrees Fahrenheit water that is used for space heating and then injected; the wells are spaced 250 ft apart. Tracer breakthrough was observed in 2 hours and 45 minutes in the production well, indicating fracture flow. However, the tracer concentrations were low and indicated porous media flow; the tracers mixed with a reservoir volume much larger than a fracture.

Optimization of an electrostatic quadrupole doublet focusing systems

Energy Technology Data Exchange (ETDEWEB)

Hussein, Oday A., E-mail: oah@sc.nahrainuniv.edu.iq [Department of Physics, College of Science, Al-Nahrain University, Baghdad (Iraq); Sise, Omer [Department of Science Education, Faculty of Education, Suleyman Demirel University, Isparta (Turkey)

2017-05-15

Highlights: • The imaging properties of an electrostatic quadrupole doublet lens were analyzed with the aid of computer simulation. • The optimal electrode voltages which lead to stigmatic image in both planes of the quadrupole doublet lens with minimum spot size at position sensitive detector (PSD) were found for two operation modes: point-to-point focusing and parallel-to-point focusing. • The imaging properties of are very sensitive to the lunching angle of the electron-beam. - Abstract: The imaging properties of an electrostatic quadrupole doublet lens were analyzed with the aid of computer simulation. The optimal electrode voltages which lead to stigmatic image in both planes of the quadrupole doublet lens with minimum spot size at position sensitive detector (PSD) were found for two operation modes: point-to-point focusing and parallel-to-point focusing. The optical properties as: Magnifications, spot sizes in the image plane and aberration figures were discussed. The results showed that the focusing of the lens was strong in the xy-plane in comparison with the focusing in the xz-plane. The distortion of the image was greater when the image position will be close to the lens in comparison with object position. Also, the imaging properties were very sensitive to the lunching angle of the electron-beam.

On chiral and non chiral 1D supermultiplets

Energy Technology Data Exchange (ETDEWEB)

Toppan, Francesco, E-mail: toppan@cbpf.b [Centro Brasileiro de Pesquisas Fisicas (TEO/CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Fisica Teorica

2011-07-01

In this talk I discuss and clarify some issues concerning chiral and non chiral properties of the one-dimensional supermultiplets of the N-extended supersymmetry. Quaternionic chirality can be defined for N = 4, 5, 6, 7, 8. Octonionic chirality for N = 8 and beyond. Inequivalent chiralities only arise when considering several copies of N = 4 or N = 8 supermultiplets. (author)

On chiral and non chiral 1D supermultiplets

International Nuclear Information System (INIS)

Toppan, Francesco

2011-01-01

In this talk I discuss and clarify some issues concerning chiral and non chiral properties of the one-dimensional supermultiplets of the N-extended supersymmetry. Quaternionic chirality can be defined for N = 4, 5, 6, 7, 8. Octonionic chirality for N = 8 and beyond. Inequivalent chiralities only arise when considering several copies of N = 4 or N = 8 supermultiplets. (author)

Doublet III beamline: as-built

International Nuclear Information System (INIS)

Harder, C.R.; Holland, M.M.; Parker, J.W.; Gunn, J.; Resnick, L.

1980-03-01

In order to fully exploit Doublet III capabilities and to study new plasma physics regimes, a Neutral Beam Injector System has been constructed. Initially, a two beamline system will supply 7 MW of heat to the plasma. The system is currently being expanded to inject approx. 20 MW of power (6 beamlines). Each beamline is equipped with two Lawrence Berkeley Laboratory type rectangular ion sources with 10 cm x 40 cm extraction grids. These sources will accelerate hydrogen ions to 80 keV, with extracted beam currents in excess of 80 A per source expected. The first completed source is currently being tested and conditioned on the High Voltage Test Stand at Lawrence Livermore Laboratory. This paper pictorially reviews the as-built Doublet III neutral beamline with emphasis on component relation and configuration relative to spatial and source imposed design constraints

Chiral anomaly and anomalous finite-size conductivity in graphene

Science.gov (United States)

Shen, Shun-Qing; Li, Chang-An; Niu, Qian

2017-09-01

Graphene is a monolayer of carbon atoms packed into a hexagon lattice to host two spin degenerate pairs of massless two-dimensional Dirac fermions with different chirality. It is known that the existence of non-zero electric polarization in reduced momentum space which is associated with a hidden chiral symmetry will lead to the zero-energy flat band of a zigzag nanoribbon and some anomalous transport properties. Here it is proposed that the Adler-Bell-Jackiw chiral anomaly or non-conservation of chiral charges of Dirac fermions at different valleys can be realized in a confined ribbon of finite width, even in the absence of a magnetic field. In the laterally diffusive regime, the finite-size correction to conductivity is always positive and is inversely proportional to the square of the lateral dimension W, which is different from the finite-size correction inversely proportional to W from the boundary modes. This anomalous finite-size conductivity reveals the signature of the chiral anomaly in graphene, and it is measurable experimentally. This finding provides an alternative platform to explore the purely quantum mechanical effect in graphene.

Separation of the 1+/1− parity doublet in 20Ne

Directory of Open Access Journals (Sweden)

J. Beller

2015-02-01

Full Text Available The (J,T=(1,1 parity doublet in 20Ne at 11.26 MeV is a good candidate to study parity violation in nuclei. However, its energy splitting is known with insufficient accuracy for quantitative estimates of parity violating effects. To improve on this unsatisfactory situation, nuclear resonance fluorescence experiments using linearly and circularly polarized γ-ray beams were used to determine the energy difference of the parity doublet ΔE=E(1−−E(1+=−3.2(±0.7stat(−1.2+0.6sys keV and the ratio of their integrated cross sections Is,0(+/Is,0(−=29(±3stat(−7+14sys. Shell-model calculations predict a parity-violating matrix element having a value in the range 0.46–0.83 eV for the parity doublet. The small energy difference of the parity doublet makes 20Ne an excellent candidate to study parity violation in nuclear excitations. Keywords: Parity doublet, Parity violation

M DWARF LUMINOSITY, RADIUS, AND α-ENRICHMENT FROM I-BAND SPECTRAL FEATURES

Energy Technology Data Exchange (ETDEWEB)

Terrien, Ryan C.; Mahadevan, Suvrath; Bender, Chad F.; Deshpande, Rohit; Robertson, Paul, E-mail: rct151@psu.edu [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

2015-03-20

Despite the ubiquity of M dwarfs and their growing importance to studies of exoplanets, Galactic evolution, and stellar structure, methods for precisely measuring their fundamental stellar properties remain elusive. Existing techniques for measuring M dwarf luminosity, mass, radius, or composition are calibrated over a limited range of stellar parameters or require expensive observations. We find a strong correlation between the K{sub S}-band luminosity (M{sub K}), the observed strength of the I-band sodium doublet absorption feature, and [Fe/H] in M dwarfs without strong Hα emission. We show that the strength of this feature, coupled with [Fe/H] and spectral type, can be used to derive M dwarf M{sub K} and radius without requiring parallax. Additionally, we find promising evidence that the strengths of the I-band sodium doublet and the nearby I-band calcium triplet may jointly indicate α-element enrichment. The use of these I-band features requires only moderate-resolution near-infrared spectroscopy to provide valuable information about the potential habitability of exoplanets around M dwarfs, and surface gravity and distance for M dwarfs throughout the Galaxy. This technique has immediate applicability for both target selection and candidate planet–host system characterization for exoplanet missions such as TESS and K2.

M DWARF LUMINOSITY, RADIUS, AND α-ENRICHMENT FROM I-BAND SPECTRAL FEATURES

International Nuclear Information System (INIS)

Terrien, Ryan C.; Mahadevan, Suvrath; Bender, Chad F.; Deshpande, Rohit; Robertson, Paul

2015-01-01

Despite the ubiquity of M dwarfs and their growing importance to studies of exoplanets, Galactic evolution, and stellar structure, methods for precisely measuring their fundamental stellar properties remain elusive. Existing techniques for measuring M dwarf luminosity, mass, radius, or composition are calibrated over a limited range of stellar parameters or require expensive observations. We find a strong correlation between the K S -band luminosity (M K ), the observed strength of the I-band sodium doublet absorption feature, and [Fe/H] in M dwarfs without strong Hα emission. We show that the strength of this feature, coupled with [Fe/H] and spectral type, can be used to derive M dwarf M K and radius without requiring parallax. Additionally, we find promising evidence that the strengths of the I-band sodium doublet and the nearby I-band calcium triplet may jointly indicate α-element enrichment. The use of these I-band features requires only moderate-resolution near-infrared spectroscopy to provide valuable information about the potential habitability of exoplanets around M dwarfs, and surface gravity and distance for M dwarfs throughout the Galaxy. This technique has immediate applicability for both target selection and candidate planet–host system characterization for exoplanet missions such as TESS and K2

Strong Quantum Confinement Effects and Chiral Excitons in Bio-Inspired ZnO–Amino Acid Cocrystals

KAUST Repository

Muhammed, Madathumpady Abubaker Habeeb

2018-02-20

Elucidating the underlying principles behind band gap engineering is paramount for the successful implementation of semiconductors in photonic and optoelectronic devices. Recently it has been shown that the band gap of a wide and direct band gap semiconductor, such as ZnO, can be modified upon cocrystallization with amino acids, with the role of the biomolecules remaining unclear. Here, by probing and modeling the light-emitting properties of ZnO-amino acid cocrystals, we identify the amino acids\\' role on this band gap modulation and demonstrate their effective chirality transfer to the interband excitations in ZnO. Our 3D quantum model suggests that the strong band edge emission blue-shift in the cocrystals can be explained by a quasi-periodic distribution of amino acid potential barriers within the ZnO crystal lattice. Overall, our findings indicate that biomolecule cocrystallization can be used as a truly bio-inspired means to induce chiral quantum confinement effects in quasi-bulk semiconductors.

Separation of the 1+ /1- parity doublet in 20Ne

Science.gov (United States)

Beller, J.; Stumpf, C.; Scheck, M.; Pietralla, N.; Deleanu, D.; Filipescu, D. M.; Glodariu, T.; Haxton, W.; Idini, A.; Kelley, J. H.; Kwan, E.; Martinez-Pinedo, G.; Raut, R.; Romig, C.; Roth, R.; Rusev, G.; Savran, D.; Tonchev, A. P.; Tornow, W.; Wagner, J.; Weller, H. R.; Zamfir, N.-V.; Zweidinger, M.

2015-02-01

The (J , T) = (1 , 1) parity doublet in 20Ne at 11.26 MeV is a good candidate to study parity violation in nuclei. However, its energy splitting is known with insufficient accuracy for quantitative estimates of parity violating effects. To improve on this unsatisfactory situation, nuclear resonance fluorescence experiments using linearly and circularly polarized γ-ray beams were used to determine the energy difference of the parity doublet ΔE = E (1-) - E (1+) = - 3.2(± 0.7) stat(-1.2+0.6)sys keV and the ratio of their integrated cross sections Is,0(+) /Is,0(-) = 29(± 3) stat(-7+14)sys. Shell-model calculations predict a parity-violating matrix element having a value in the range 0.46-0.83 eV for the parity doublet. The small energy difference of the parity doublet makes 20Ne an excellent candidate to study parity violation in nuclear excitations.

Derivative interactions and perturbative UV contributions in N Higgs doublet models

Energy Technology Data Exchange (ETDEWEB)

Kikuta, Yohei [KEK Theory Center, KEK, Tsukuba (Japan); The Graduate University for Advanced Studies, Department of Particle and Nuclear Physics, Tsukuba (Japan); Yamamoto, Yasuhiro [Universidad de Granada, Deportamento de Fisica Teorica y del Cosmos, Facultad de Ciencias and CAFPE, Granada (Spain)

2016-05-15

We study the Higgs derivative interactions on models including arbitrary number of the Higgs doublets. These interactions are generated by two ways. One is higher order corrections of composite Higgs models, and the other is integration of heavy scalars and vectors. In the latter case, three point couplings between the Higgs doublets and these heavy states are the sources of the derivative interactions. Their representations are constrained to couple with the doublets. We explicitly calculate all derivative interactions generated by integrating out. Their degrees of freedom and conditions to impose the custodial symmetry are discussed. We also study the vector boson scattering processes with a couple of two Higgs doublet models to see experimental signals of the derivative interactions. They are differently affected by each heavy field. (orig.)

Origin and phenomenology of weak-doublet spin-1 bosons

International Nuclear Information System (INIS)

Chizhov, M.V.; Dvali, Gia

2011-01-01

We study phenomenological consequences of the Standard Model extension by the new spin-1 fields with the internal quantum numbers of the electroweak Higgs doublets. We show, that there are at least three different classes of theories, all motivated by the hierarchy problem, which predict appearance of such vector weak-doublets not far from the weak scale. The common feature for all the models is the existence of an SU(3) W gauge extension of the weak SU(2) W group, which is broken down to the latter at some energy scale around TeV. The Higgs doublet then emerges as either a pseudo-Nambu-Goldstone boson of a global remnant of SU(3) W , or as a symmetry partner of the true eaten-up Goldstone boson. In the third class, the Higgs is a scalar component of a high-dimensional SU(3) W gauge field. The common phenomenological feature of these theories is the existence of the electroweak doublet vectors (Z * ,W * ), which in contrast to well-known Z ' and W ' bosons posses only anomalous (magnetic moment type) couplings with ordinary light fermions. This fact leads to some unique signatures for their detection at the hadron colliders.

Scalar production in models with 1 and 2 Higgs doublets

International Nuclear Information System (INIS)

Campos Carvalho, F.L. de.

1991-03-01

A standard electroweak interaction model is studied based on the introduction of an additional scalar doublet which rises two neutral scalars, one pseudoscalar and two charged scalars. The doublet introduction gives the possibility to implement constraints issued by the supersymmetry, restricting therefore those scalar masses. (L.C.J.A.)

Siegel's chiral boson and the chiral Schwinger model

International Nuclear Information System (INIS)

Berger, T.

1992-01-01

In this paper Siegel's proposal for a Lagrangian formulation of a chiral boson is analyzed by applying recent results on 2d chiral quantum gravity. A model is derived whose solution consists of a massive scalar and two massless chiral scalars. Therefore it is a minimally bosonized two-fermion chiral Schwinger model

Two-chiral component microemulsion EKC - chiral surfactant and chiral oil. Part 2: diethyl tartrate.

Science.gov (United States)

Kahle, Kimberly A; Foley, Joe P

2007-08-01

In this second study on dual-chirality microemulsions containing a chiral surfactant and a chiral oil, a less hydrophobic and lower interfacial tension chiral oil, diethyl tartrate, is employed (Part 1, Foley, J. P. et al.., Electrophoresis, DOI: 10.1002/elps.200600551). Six stereochemical combinations of dodecoxycarbonylvaline (DDCV: R, S, or racemic, 2.00% w/v), racemic 2-hexanol (1.65% v/v), and diethyl tartrate (D, L, or racemic, 0.88% v/v) were examined as pseudostationary phases (PSPs) for the enantioseparation of six chiral pharmaceutical compounds: pseudoephedrine, ephedrine, N-methyl ephedrine, metoprolol, synephrine, and atenolol. Average efficiencies increased with the addition of a chiral oil to R-DDCV PSP formulations. Modest improvements in resolution and enantioselectivity (alpha(enant)) were achieved with two-chiral-component systems over the one-chiral-component microemulsion. Slight enantioselective synergies were confirmed using a thermodynamic model. Results obtained in this study are compared to those obtained in Part 1 as well as those obtained with chiral MEEKC using an achiral, low-interfacial-tension oil (ethyl acetate). Dual-chirality microemulsions with the more hydrophobic oil dibutyl tartrate yielded, relative to diethyl tartrate, higher efficiencies (100,000-134,000 vs. 80,800-94,300), but lower resolution (1.64-1.91 vs. 2.08-2.21) due to lower enantioselectivities (1.060-1.067 vs. 1.078-1.081). Atenolol enantiomers could not be separated with the dibutyl tartrate-based microemulsions but were partially resolved using diethyl tartrate microemulsions. A comparable single-chirality microemulsion based on the achiral oil ethyl acetate yielded, relative to diethyl tartrate, lower efficiency (78 300 vs. 91 600), higher resolution (1.99 vs. 1.83), and similar enantioselectivities.

Effect of diameter and chirality on the structure and electronic properties of BC2N nanotubes

International Nuclear Information System (INIS)

Akhavan, Mojdeh; Jalili, Seifollah; Schofield, Jeremy

2015-01-01

Highlights: • BC 2 N nanotubes with different diameters and four chirality types are studied. • Two lowest-diameter zigzag BC 2 N tubes are metallic and others are semiconducting. • Band gap of zigzag tubes is more sensitive to diameter compared to armchair tubes. • Even–odd oscillation is observed for the band gap of one kind of zigzag tubes. • The energy and band gap for large-diameter tubes converge to BC 2 N sheet values. - Abstract: Density functional theory calculations are used to investigate a series of BC 2 N nanotubes with a wide range of diameters. Two types of zigzag and two types of armchair nanotubes are studied to survey the effect of diameter and chirality on energetics and electronic properties of nanotubes. Two nanotubes are found to be metallic and others show semiconducting behavior. The diameter is shown to have a greater impact on the band gap of zigzag nanotubes than those of armchair tubes. (n, 0) zigzag nanotubes show an even–odd band gap oscillation, which can be explained by the electron density distribution of the lowest unoccupied crystalline orbital. The stability of the nanotubes is also assessed using strain energies and it is shown that the strain energy does not depend on nanotube type and chirality. In the limit of large diameters, the geometry and band gap of all nanotubes converge to BC 2 N sheet data

New final doublets and power densities for the international linear ...

Indian Academy of Sciences (India)

Abstract. In this paper we use current and proposed final doublet magnet technologies to reoptimise the interaction region of the international linear collider and reduce the power losses. The result is a set of three new final doublet layouts with improved beam transport properties. The effect of localised power deposition and ...

Two-chiral-component microemulsion electrokinetic chromatography-chiral surfactant and chiral oil: part 1. dibutyl tartrate.

Science.gov (United States)

Kahle, Kimberly A; Foley, Joe P

2007-06-01

The first simultaneous use of a chiral surfactant and a chiral oil for microemulsion EKC (MEEKC) is reported. Six stereochemical combinations of dodecoxycarbonylvaline (DDCV: R, S, or racemic, 2.00% w/v), racemic 2-hexanol (1.65% v/v), and dibutyl tartrate (D, L, or racemic, 1.23% v/v) were examined as chiral pseudostationary phases (PSPs) for the separation of six pairs of pharmaceutical enantiomers: pseudoephedrine, ephedrine, N-methyl ephedrine, metoprolol, synephrine, and atenolol. Subtle differences were observed for three chromatographic figures of merit (alpha(enant), alpha(meth), k) among the chiral microemulsions; a moderate difference was observed for efficiency (N) and elution range. Dual-chirality microemulsions provided both the largest and smallest enantioselectivities, due to small positive and negative synergies between the chiral microemulsion components. For the ephedrine family of compounds, dual-chiral microemulsions with surfactant and oil in opposite stereochemical configurations provided higher enantioselectivities than the single-chiral component microemulsion (RXX), whereas dual-chiral microemulsions with surfactant and oil in the same stereochemical configurations provided lower enantioselectivities than RXX. Slight to moderate enantioselective synergies were confirmed using a thermodynamic model. Efficiencies observed with microemulsions comprised of racemic dibutyl tartrate or dibutyl-D-tartrate were significantly higher than those obtained with dibutyl-L-tartrate, with an average difference in plate count of about 25 000. Finally, one two-chiral-component microemulsion (RXS) provided significantly better resolution than the remaining one- and two-chiral-component microemulsions for the ephedrine-based compounds, but only slightly better or equivalent resolution for non-ephedrine compounds.

Temporal changes of the inner core from waveform doublets

Science.gov (United States)

Yang, Y.; Song, X.

2017-12-01

Temporal changes of the Earth's inner core have been detected from earthquake waveform doublets (repeating sources with similar waveforms at the same station). Using doublets from events up to the present in the South Sandwich Island (SSI) region recorded by the station COLA (Alaska), we confirmed systematic temporal variations in the travel time of the inner-core-refracted phase (PKIKP, the DF branch). The DF phase arrives increasingly earlier than outer core phases (BC and AB) by rate of approximately 0.07 s per decade since 1970s. If we assume that the temporal change is caused by a shift of the lateral gradient from the inner core rotation as in previous studies, we estimate the rotation rate of 0.2-0.4 degree per year. We also analyzed the topography of the inner core boundary (ICB) using SSI waveform doublets recorded by seismic stations in Eurasia and North America with reflected phase (PKiKP) and refracted phases. There are clear temporal changes in the waveforms of doublets for PKiKP under Africa and Central America. In addition, for doublets recorded by three nearby stations (AAK, AML, and UCH), we observed systematic change in the relative travel time of PKiKP and PKIKP. The temporal change of the (PKiKP - PKIKP) differential time is always negative for the event pairs if both events are before 2007, while it fluctuates to positive if the later event occurs after 2007. The rapid temporal changes in space and time may indicate localized processes (e.g., freezing and melting) of the ICB in the recent decades under Africa. We are exploring 4D models consistent with the temporal changes.

Strain-induced chiral magnetic effect in Weyl semimetals

International Nuclear Information System (INIS)

Cortijo, Alberto; Kharzeev, Dmitri; Vozmediano, Maria A. H.

2016-01-01

Here, we argue that strain applied to a time-reversal and inversion breaking Weyl semimetal in a magnetic field can induce an electric current via the chiral magnetic effect. A tight-binding model is used to show that strain generically changes the locations in the Brillouin zone but also the energies of the band touching points (tips of the Weyl cones). Since axial charge in a Weyl semimetal can relax via intervalley scattering processes, the induced current will decay with a time scale given by the lifetime of a chiral quasiparticle. Lastly, we estimate the strength and lifetime of the current for typical material parameters and find that it should be experimentally observable.

Two-Higgs-doublet models with Minimal Flavour Violation

International Nuclear Information System (INIS)

Carlucci, Maria Valentina

2010-01-01

The tree-level flavour-changing neutral currents in the two-Higgs-doublet models can be suppressed by protecting the breaking of either flavour or flavour-blind symmetries, but only the first choice, implemented by the application of the Minimal Flavour Violation hypothesis, is stable under quantum corrections. Moreover, a two-Higgs-doublet model with Minimal Flavour Violation enriched with flavour-blind phases can explain the anomalies recently found in the ΔF = 2 transitions, namely the large CP-violating phase in B s mixing and the tension between ε K and S ψKS .

Homochiral Evolution in Self-Assembled Chiral Polymers and Block Copolymers.

Science.gov (United States)

Wen, Tao; Wang, Hsiao-Fang; Li, Ming-Chia; Ho, Rong-Ming

2017-04-18

The significance of chirality transfer is not only involved in biological systems, such as the origin of homochiral structures in life but also in man-made chemicals and materials. How the chiral bias transfers from molecular level (molecular chirality) to helical chain (conformational chirality) and then to helical superstructure or phase (hierarchical chirality) from self-assembly is vital for the chemical and biological processes in nature, such as communication, replication, and enzyme catalysis. In this Account, we summarize the methodologies for the examination of homochiral evolution at different length scales based on our recent studies with respect to the self-assembly of chiral polymers and chiral block copolymers (BCPs*). A helical (H*) phase to distinguish its P622 symmetry from that of normal hexagonally packed cylinder phase was discovered in the self-assembly of BCPs* due to the chirality effect on BCP self-assembly. Enantiomeric polylactide-containing BCPs*, polystyrene-b-poly(l-lactide) (PS-PLLA) and polystyrene-b-poly(d-lactide) (PS-PDLA), were synthesized for the examination of homochiral evolution. The optical activity (molecular chirality) of constituted chiral repeating unit in the chiral polylactide is detected by electronic circular dichroism (ECD) whereas the conformational chirality of helical polylactide chain can be explicitly determined by vibrational circular dichroism (VCD). The H* phases of the self-assembled polylactide-containing BCPs* can be directly visualized by 3D transmission electron microscopy (3D TEM) technique at which the handedness (hierarchical chirality) of the helical nanostructure is thus determined. The results from the ECD, VCD, and 3D TEM for the investigated chirality at different length scales suggest the homochiral evolution in the self-assembly of the BCPs*. For chiral polylactides, twisted lamellae in crystalline banded spherulite can be formed by dense packing scheme and effective interactions upon helical

Chiral superconductors.

Science.gov (United States)

Kallin, Catherine; Berlinsky, John

2016-05-01

Chiral superconductivity is a striking quantum phenomenon in which an unconventional superconductor spontaneously develops an angular momentum and lowers its free energy by eliminating nodes in the gap. It is a topologically non-trivial state and, as such, exhibits distinctive topological modes at surfaces and defects. In this paper we discuss the current theory and experimental results on chiral superconductors, focusing on two of the best-studied systems, Sr2RuO4, which is thought to be a chiral triplet p-wave superconductor, and UPt3, which has two low-temperature superconducting phases (in zero magnetic field), the lower of which is believed to be chiral triplet f-wave. Other systems that may exhibit chiral superconductivity are also discussed. Key signatures of chiral superconductivity are surface currents and chiral Majorana modes, Majorana states in vortex cores, and the possibility of half-flux quantum vortices in the case of triplet pairing. Experimental evidence for chiral superconductivity from μSR, NMR, strain, polar Kerr effect and Josephson tunneling experiments are discussed.

Chiral Recognition and Separation by Chirality-Enriched Metal-Organic Frameworks.

Science.gov (United States)

Das, Saikat; Xu, Shixian; Ben, Teng; Qiu, Shilun

2018-05-16

Endowed with chiral channels and pores, chiral metal-organic frameworks (MOFs) are highly useful; however, their synthesis remains a challenge given that most chiral building blocks are expensive. Although MOFs with induced chirality have been reported to avoid this shortcoming, no study providing evidence for the ee value of such MOFs has yet been reported. We herein describe the first study on the efficiency of chiral induction in MOFs using inexpensive achiral building blocks and fully recoverable chiral dopants to control the handedness of racemic MOFs. This method yielded chirality-enriched MOFs with accessible pores. The ability of the materials to form host-guest complexes was probed with enantiomers of varying size and coordination and in solvents with varying polarity. Furthermore, mixed-matrix membranes (MMMs) composed of chirality-enriched MOF particles dispersed in a polymer matrix demonstrated a new route for chiral separation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effective Field Theory with Two Higgs Doublets

CERN Document Server

Crivellin, Andreas; Procura, Massimiliano

2016-01-01

In this article we extend the effective field theory framework describing new physics effects to the case where the underlying low-energy theory is a Two-Higgs-Doublet model. We derive a complete set of independent operators up to dimension six assuming a $Z_2$-invariant CP-conserving Higgs potential. The effects on Higgs and gauge boson masses, mixing angles in the Higgs sector as well as couplings to fermions and gauge bosons are computed. At variance with the case of a single Higgs doublet, we find that pair production of SM-like Higgses, arising through dimension-six operators, is not fixed by fermion-fermion-Higgs couplings and can therefore be sizable.

Optical Selection Rule of Excitons in Gapped Chiral Fermion Systems

Science.gov (United States)

Zhang, Xiaoou; Shan, Wen-Yu; Xiao, Di

2018-02-01

We show that the exciton optical selection rule in gapped chiral fermion systems is governed by their winding number w , a topological quantity of the Bloch bands. Specifically, in a CN-invariant chiral fermion system, the angular momentum of bright exciton states is given by w ±1 +n N with n being an integer. We demonstrate our theory by proposing two chiral fermion systems capable of hosting dark s -like excitons: gapped surface states of a topological crystalline insulator with C4 rotational symmetry and biased 3 R -stacked MoS2 bilayers. In the latter case, we show that gating can be used to tune the s -like excitons from bright to dark by changing the winding number. Our theory thus provides a pathway to electrical control of optical transitions in two-dimensional material.

Doublet III neutral beam multi-stream command language system

International Nuclear Information System (INIS)

Campbell, L.; Garcia, J.R.

1983-01-01

A multi-stream command language system was developed to provide control of the dual source neutral beam injectors on the Doublet III experiment at GA Technologies Inc. The Neutral Beam command language system consists of three parts: compiler, sequencer, and interactive task. The command language, which was derived from the Doublet III tokamak command language, POPS, is compiled, using a recursive descent compiler, into reverse polish notation instructions which then can be executed by the sequencer task. The interactive task accepts operator commands via a keyboard. The interactive task directs the operation of three input streams, creating commands which are then executed by the sequencer. The streams correspond to the two sources within a Doublet III neutral beam, plus an interactive stream. The sequencer multiplexes the execution of instructions from these three streams. The instructions include reads and writes to an operator terminal, arithmetic computations, intrinsic functions such as CAMAC input and output, and logical instructions. The neutral beam command language system was implemented using Modular Computer Systems (ModComp) Pascal and consists of two tasks running on a ModComp Classic IV computer. The two tasks, the interactive and the sequencer, run independently and communicate using shared memory regions. The compiler runs as an overlay to the interactive task when so directed by operator commands. The system is succesfully being used to operate the three neutral beams on Doublet III

Chiral Magnetic Spirals

International Nuclear Information System (INIS)

Basar, Goekce; Dunne, Gerald V.; Kharzeev, Dmitri E.

2010-01-01

We argue that the presence of a very strong magnetic field in the chirally broken phase induces inhomogeneous expectation values, of a spiral nature along the magnetic field axis, for the currents of charge and chirality, when there is finite baryon density or an imbalance between left and right chiralities. This 'chiral magnetic spiral' is a gapless excitation transporting the currents of (i) charge (at finite chirality), and (ii) chirality (at finite baryon density) along the direction of the magnetic field. In both cases it also induces in the transverse directions oscillating currents of charge and chirality. In heavy ion collisions, the chiral magnetic spiral possibly provides contributions both to the out-of-plane and the in-plane dynamical charge fluctuations recently observed at BNL RHIC.

Chiral Spirals from Discontinuous Chiral Symmetry

Science.gov (United States)

Kojo, Toru

2014-09-01

Recently phases of the inhomongeneous chiral condensates (IChC) attract renewed attentions in quark matter context. A number of theoretical studies have suggested that in some domain of moderate quark density the IChC phases are energetically more favored than the normal, chiral symmetric phase. In particular, the NJL-type model studies indicate that the phase of IChCs may mask the usual 1st order chiral phase transition line and its critical end point, and might change the conventional wisdom. In this talk, I will discuss characteristic features of the IChC phases and their potential impacts on the compact star physics. In particular, some of the IChC phases open gaps near the quark Fermi surface, suppressing back-reaction from the quark to gluon sectors. This mechanism delays the chiral restoration in the strange quark sector, forbids the emergence of the large bag constant, and as a consequence, makes the quark matter EOS very stiff. Recently phases of the inhomongeneous chiral condensates (IChC) attract renewed attentions in quark matter context. A number of theoretical studies have suggested that in some domain of moderate quark density the IChC phases are energetically more favored than the normal, chiral symmetric phase. In particular, the NJL-type model studies indicate that the phase of IChCs may mask the usual 1st order chiral phase transition line and its critical end point, and might change the conventional wisdom. In this talk, I will discuss characteristic features of the IChC phases and their potential impacts on the compact star physics. In particular, some of the IChC phases open gaps near the quark Fermi surface, suppressing back-reaction from the quark to gluon sectors. This mechanism delays the chiral restoration in the strange quark sector, forbids the emergence of the large bag constant, and as a consequence, makes the quark matter EOS very stiff. NSF Grants PHY09-69790, PHY13-05891.

Oriented circular dichroism analysis of chiral surface-anchored metal-organic frameworks grown by liquid-phase epitaxy and upon loading with chiral guest compounds

KAUST Repository

Gu, Zhigang

2014-06-17

Oriented circular dichroism (OCD) is explored and successfully applied to investigate chiral surface-anchored metal-organic frameworks (SURMOFs) based on camphoric acid (D- and Lcam) with the composition [Cu2(Dcam) 2x(Lcam)2-2x(dabco)]n (dabco=1,4-diazabicyclo- [2.2.2]-octane). The three-dimensional chiral SURMOFs with high-quality orientation were grown on quartz glass plates by using a layer-by-layer liquid-phase epitaxy method. The growth orientation, as determined by X-ray diffraction (XRD), could be switched between the [001] and [110] direction by using either OH- or COOH-terminated substrates. These SURMOFs were characterized by using OCD, which confirmed the ratio as well as the orientation of the enantiomeric linker molecules. Theoretical computations demonstrate that the OCD band intensities of the enantiopure [Cu2(Dcam)2(dabco)] n grown in different orientations are a direct result of the anisotropic nature of the chiral SURMOFs. Finally, the enantiopure [Cu 2(Dcam)2(dabco)]n and [Cu2(Lcam) 2(dabco)]n SURMOFs were loaded with the two chiral forms of ethyl lactate [(+)-ethyl-D-lactate and (-)-ethyl-L-lactate)]. An enantioselective enrichment of >60 % was observed by OCD when the chiral host scaffold was loaded from the racemic mixture. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oriented circular dichroism analysis of chiral surface-anchored metal-organic frameworks grown by liquid-phase epitaxy and upon loading with chiral guest compounds

KAUST Repository

Gu, Zhigang; Bü rck, Jochen; Bihlmeier, Angela; Liu, Jinxuan; Shekhah, Osama; Weidler, Peter G.; Azucena, Carlos; Wang, Zhengbang; Heiß ler, Stefan; Gliemann, Hartmut; Klopper, Wim; Ulrich, Anne S.; Wö ll, Christof H.

2014-01-01

Oriented circular dichroism (OCD) is explored and successfully applied to investigate chiral surface-anchored metal-organic frameworks (SURMOFs) based on camphoric acid (D- and Lcam) with the composition [Cu2(Dcam) 2x(Lcam)2-2x(dabco)]n (dabco=1,4-diazabicyclo- [2.2.2]-octane). The three-dimensional chiral SURMOFs with high-quality orientation were grown on quartz glass plates by using a layer-by-layer liquid-phase epitaxy method. The growth orientation, as determined by X-ray diffraction (XRD), could be switched between the [001] and [110] direction by using either OH- or COOH-terminated substrates. These SURMOFs were characterized by using OCD, which confirmed the ratio as well as the orientation of the enantiomeric linker molecules. Theoretical computations demonstrate that the OCD band intensities of the enantiopure [Cu2(Dcam)2(dabco)] n grown in different orientations are a direct result of the anisotropic nature of the chiral SURMOFs. Finally, the enantiopure [Cu 2(Dcam)2(dabco)]n and [Cu2(Lcam) 2(dabco)]n SURMOFs were loaded with the two chiral forms of ethyl lactate [(+)-ethyl-D-lactate and (-)-ethyl-L-lactate)]. An enantioselective enrichment of >60 % was observed by OCD when the chiral host scaffold was loaded from the racemic mixture. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Geometrical approach to central molecular chirality: a chirality selection rule

OpenAIRE

Capozziello, S.; Lattanzi, A.

2004-01-01

Chirality is of primary importance in many areas of chemistry and has been extensively investigated since its discovery. We introduce here the description of central chirality for tetrahedral molecules using a geometrical approach based on complex numbers. According to this representation, for a molecule having n chiral centres, it is possible to define an index of chirality. Consequently a chirality selection rule has been derived which allows the characterization of a molecule as achiral, e...

An evaluation of interferences in heat production from low enthalpy geothermal doublets systems

DEFF Research Database (Denmark)

Willems, Cees J. L.; Nick, Hamidreza M.; Weltje, Gert Jan

2017-01-01

Required distance between doublet systems in low enthalpy geothermal heat exploitation is often not fully elucidated. The required distance aims to prevent negative interference influencing the utilisation efficiency of doublet systems. Currently production licence areas are often issued based...... and minimal required production temperature. The results of this study can be used to minimize negative interference or optimise positive interference aiming at improving geothermal doublet deployment efficiency. (C) 2017 The Authors. Published by Elsevier Ltd....

Chiral nanophotonics chiral optical properties of plasmonic systems

CERN Document Server

Schäferling, Martin

2017-01-01

This book describes the physics behind the optical properties of plasmonic nanostructures focusing on chiral aspects. It explains in detail how the geometry determines chiral near-fields and how to tailor their shape and strength. Electromagnetic fields with strong optical chirality interact strongly with chiral molecules and, therefore, can be used for enhancing the sensitivity of chiroptical spectroscopy techniques. Besides a short review of the latest results in the field of plasmonically enhanced enantiomer discrimination, this book introduces the concept of chiral plasmonic near-field sources for enhanced chiroptical spectroscopy. The discussion of the fundamental properties of these light sources provides the theoretical basis for further optimizations and is of interest for researchers at the intersection of nano-optics, plasmonics and stereochemistry. .

Coherent resonance stop bands in alternating gradient beam transport

Science.gov (United States)

Ito, K.; Okamoto, H.; Tokashiki, Y.; Fukushima, K.

2017-06-01

An extensive experimental study is performed to confirm fundamental resonance bands of an intense hadron beam propagating through an alternating gradient linear transport channel. The present work focuses on the most common lattice geometry called "FODO" or "doublet" that consists of two quadrupoles of opposite polarities. The tabletop ion-trap system "S-POD" (Simulator of Particle Orbit Dynamics) developed at Hiroshima University is employed to clarify the parameter-dependence of coherent beam instability. S-POD can provide a non-neutral plasma physically equivalent to a charged-particle beam in a periodic focusing potential. In contrast with conventional experimental approaches relying on large-scale machines, it is straightforward in S-POD to control the doublet geometry characterized by the quadrupole filling factor and drift-space ratio. We verify that the resonance feature does not essentially change depending on these geometric factors. A few clear stop bands of low-order resonances always appear in the same pattern as previously found with the sinusoidal focusing model. All stop bands become widened and shift to the higher-tune side as the beam density is increased. In the space-charge-dominated regime, the most dangerous stop band is located at the bare betatron phase advance slightly above 90 degrees. Experimental data from S-POD suggest that this severe resonance is driven mainly by the linear self-field potential rather than by nonlinear external imperfections and, therefore, unavoidable at high beam density. The instability of the third-order coherent mode generates relatively weak but noticeable stop bands near the phase advances of 60 and 120 degrees. The latter sextupole stop band is considerably enhanced by lattice imperfections. In a strongly asymmetric focusing channel, extra attention may have to be paid to some coupling resonance lines induced by the Coulomb potential. Our interpretations of experimental data are supported by theoretical

On the interplay between chirality and exciton coupling: a DFT calculation of the circular dichroism in π-stacked ethylene.

Science.gov (United States)

Norman, Patrick; Linares, Mathieu

2014-09-01

The chirality of stacked weakly interacting π-systems was interpreted in terms of Frenkel exciton states and the formation of excitonic circular dichroism (CD) bands was monitored for ethylene stacks of varying sizes. Convergence of CD bands with respect to the system size was observed for stacks involving around 10 molecules. By means of rotation around the C-C double bond in ethylene, chirality was induced in the monomeric system and which was shown to dominate the spectral responses, even for polymer aggregates. In helical assemblies of chiral entities, there will always be a mix of excitonic and monomeric contributions to the CD signal and it is demonstrated that the complex polarization propagator approach in combination with Density Functional Theory is a suitable method to address this situation. © 2014 Wiley Periodicals, Inc.

A model for quasi parity-doublet spectra with strong coriolis mixing

International Nuclear Information System (INIS)

Minkov, N.; Drenska, S.; Strecker, M.

2013-01-01

The model of coherent quadrupole and octupole motion (CQOM) is combined with the reflection-asymmetric deformed shell model (DSM) in a way allowing fully microscopic description of the Coriolis decoupling and K-mixing effects in the quasi parity-doublet spectra of odd-mass nuclei. In this approach the even-even core is considered within the CQOM model, while the odd nucleon is described within DSM with pairing interaction. The Coriolis decoupling/mixing factors are calculated through a parity-projection of the single-particle wave function. Expressions for the Coriolis mixed quasi parity-doublet levels are obtained in the second order of perturbation theory, while the K-mixed core plus particle wave function is obtained in the first order. Expressions for the B(E1), B(E2) and B(E3) reduced probabilities for transitions within and between different quasi-doublets are obtained by using the total K-mixed wave function. The model scheme is elaborated in a form capable of describing the yrast and non-yrast quasi parity-doublet spectra in odd-mass nuclei. (author)

[Research on the emission spectrum of NO molecule's γ-band system by corona discharge].

Science.gov (United States)

Zhai, Xiao-dong; Ding, Yan-jun; Peng, Zhi-min; Luo, Rui

2012-05-01

The optical emission spectrum of the gamma-band system of NO molecule, A2 sigma+ --> X2 pi(r), has been analyzed and calculated based on the energy structure of NO molecule' doublet states. By employing the theory of diatomic molecular Spectra, some key parameters of equations for the radiative transition intensity were evaluated theoretically, including the potentials of the doublet states of NO molecule's upper and lower energy levels, the electronic transition moments calculated by using r-centroid approximation method, and the Einstein coefficient of different vibrational and rotational levels. The simulated spectrum of the gamma-band system was calculated as a function of different vibrational and rotational temperature. Compared to the theoretical spectroscopy, the measured results were achieved from corona discharge experiments of NO and N2. The vibrational and rotational temperatures were determined approximately by fitting the measured spectral intensities with the calculated ones.

Generation of doublet spectral lines at self-seeded X-ray FELs

Energy Technology Data Exchange (ETDEWEB)

Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2010-11-15

Self-seeding schemes, consisting of two undulators with a monochromator in between, aim to reduce the bandwidth of SASE X-ray FELs. We recently proposed to use a new method of monochromatization exploiting a single crystal in Braggtransmission geometry for self-seeding in the hard X-ray range. The obvious and technically possible extension is to use such kind of monochromator setup with two -or more- crystals arranged in a series to spectrally filter the SASE radiation at two -or more- closely-spaced wavelengths within the FEL gain band. This allows for the production of doublet- or multiplet-spectral lines. Applications exist over a broad range of hard X-ray wavelengths involving any process where there is a large change in cross section over a narrow wavelength range, as in multiple wavelength anomalous diffraction techniques (MAD). In this paper we consider the simultaneous operation of the LCLS hard X-ray FEL at two closely spaced wavelengths. We present simulation results for the LCLS baseline, and we show that this method can produce fully coherent radiation shared between two longitudinal modes. Mode spacing can be easily tuned within the FEL gain band, i.e. within 10 eV. An interesting aspect of the proposed scheme is a way of modulating the electron bunch at optical frequencies without a seed quantum laser. In fact, the XFEL output intensity contains an oscillating ''mode-beat'' component whose frequency is related to the frequency difference between the pair of longitudinal modes considered. Thus, at saturation one obtains FEL-induced modulations of energy loss and energy spread in the electron bunch at optical frequency. These modulations can be converted into density modulation at the same optical frequency with the help of a weak chicane installed behind the baseline undulator. Powerful coherent radiation can then be generated with the help of an optical transition radiation (OTR) station,which have important applications. In this paper we briefly

Generation of doublet spectral lines at self-seeded X-ray FELs

International Nuclear Information System (INIS)

Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

2010-11-01

Self-seeding schemes, consisting of two undulators with a monochromator in between, aim to reduce the bandwidth of SASE X-ray FELs. We recently proposed to use a new method of monochromatization exploiting a single crystal in Braggtransmission geometry for self-seeding in the hard X-ray range. The obvious and technically possible extension is to use such kind of monochromator setup with two -or more- crystals arranged in a series to spectrally filter the SASE radiation at two -or more- closely-spaced wavelengths within the FEL gain band. This allows for the production of doublet- or multiplet-spectral lines. Applications exist over a broad range of hard X-ray wavelengths involving any process where there is a large change in cross section over a narrow wavelength range, as in multiple wavelength anomalous diffraction techniques (MAD). In this paper we consider the simultaneous operation of the LCLS hard X-ray FEL at two closely spaced wavelengths. We present simulation results for the LCLS baseline, and we show that this method can produce fully coherent radiation shared between two longitudinal modes. Mode spacing can be easily tuned within the FEL gain band, i.e. within 10 eV. An interesting aspect of the proposed scheme is a way of modulating the electron bunch at optical frequencies without a seed quantum laser. In fact, the XFEL output intensity contains an oscillating ''mode-beat'' component whose frequency is related to the frequency difference between the pair of longitudinal modes considered. Thus, at saturation one obtains FEL-induced modulations of energy loss and energy spread in the electron bunch at optical frequency. These modulations can be converted into density modulation at the same optical frequency with the help of a weak chicane installed behind the baseline undulator. Powerful coherent radiation can then be generated with the help of an optical transition radiation (OTR) station,which have important applications. In this paper we briefly

Self-Sustained Oscillatory Sliding Movement of Doublet Microtubules and Flagellar Bend Formation.

Directory of Open Access Journals (Sweden)

Sumio Ishijima

Full Text Available It is well established that the basis for flagellar and ciliary movements is ATP-dependent sliding between adjacent doublet microtubules. However, the mechanism for converting microtubule sliding into flagellar and ciliary movements has long remained unresolved. The author has developed new sperm models that use bull spermatozoa divested of their plasma membrane and midpiece mitochondrial sheath by Triton X-100 and dithiothreitol. These models enable the observation of both the oscillatory sliding movement of activated doublet microtubules and flagellar bend formation in the presence of ATP. A long fiber of doublet microtubules extruded by synchronous sliding of the sperm flagella and a short fiber of doublet microtubules extruded by metachronal sliding exhibited spontaneous oscillatory movements and constructed a one beat cycle of flagellar bending by alternately actuating. The small sliding displacement generated by metachronal sliding formed helical bends, whereas the large displacement by synchronous sliding formed planar bends. Therefore, the resultant waveform is a half-funnel shape, which is similar to ciliary movements.

CP violation in the two-doublet Higgs sector of the MSSM

International Nuclear Information System (INIS)

Akhmetzyanova, Eh.N.; Dolgopolov, M.V.; Dubinin, M.N.

2006-01-01

Models with extended two-doublet Higgs sector are discussed in view of using their particular features to find out which sources of CP violation could take place in nature. It is considered the effective two-Higgs-doublet potential with complex parameters, when the CP invariance is broken both explicitly and spontaneously. For case of the two-doublet Higgs sector of the minimal supersymmetric model, when CP invariance is violated by the interactions of Higgs fields with the third generation of scalar quarks, the Higgs bosons mass spectrum in the case of maximal CP mixing is calculated which is significantly different from CP-conserving case. The phenomenological consequences for the Higgs mass spectrum in the decoupling regime and for the strong mixing case are considered [ru

Chiral memory via chiral amplification and selective depolymerization of porphyrin aggregates

NARCIS (Netherlands)

Helmich, F.A.; Lee, C.C.; Schenning, A.P.H.J.; Meijer, E.W.

2010-01-01

Chiral memory at the supramolecular level is obtained via a new approach using chiral Zn porphrins and achiral Cu porphyrins. In a "sergeant-and-soldiers" experiment, the Zn "sergeant" transfers its own chirality to Cu "soldiers" and, after chiral amplification, the "sergeant" is removed from the

Quasiparticle scattering image in hidden order phases and chiral superconductors

Energy Technology Data Exchange (ETDEWEB)

Thalmeier, Peter [Max Planck Institute for Chemical Physics of Solids, 01187 Dresden (Germany); Akbari, Alireza, E-mail: alireza@apctp.org [Asia Pacific Center for Theoretical Physics, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Department of Physics, and Max Planck POSTECH Center for Complex Phase Materials, POSTECH, Pohang 790-784 (Korea, Republic of)

2016-02-15

The technique of Bogoliubov quasiparticle interference (QPI) has been successfully used to investigate the symmetry of unconventional superconducting gaps, also in heavy fermion compounds. It was demonstrated that QPI can distinguish between the d-wave singlet candidates in CeCoIn{sub 5}. In URu{sub 2}Si{sub 2} presumably a chiral d-wave singlet superconducting (SC) state exists inside a multipolar hidden order (HO) phase. We show that hidden order leaves an imprint on the symmetry of QPI pattern that may be used to determine the essential question whether HO in URu{sub 2}Si{sub 2} breaks the in-plane rotational symmetry or not. We also demonstrate that the chiral d-wave SC gap leads to a crossover to a quasi-2D QPI spectrum below T{sub c} which sharpens the HO features. Furthermore we investigate the QPI image of chiral p-wave multigap superconductor Sr{sub 2}RuO{sub 4}. - Highlights: • The chiral multigap structure of Sr{sub 2}RuO{sub 4} leads to rotation of QPI spectrum with bias voltage. • 5f band reconstruction in hidden order phase of URu{sub 2}Si{sub 2} is obtained from two orbital model. • The chiral superconductivity in URu{sub 2}Si{sub 2} leads to quasi-2D quasiparticle interference (QPI).

Chiral Cliffs: Investigating the Influence of Chirality on Binding Affinity.

Science.gov (United States)

Schneider, Nadine; Lewis, Richard A; Fechner, Nikolas; Ertl, Peter

2018-05-11

Chirality is understood by many as a binary concept: a molecule is either chiral or it is not. In terms of the action of a structure on polarized light, this is indeed true. When examined through the prism of molecular recognition, the answer becomes more nuanced. In this work, we investigated chiral behavior on protein-ligand binding: when does chirality make a difference in binding activity? Chirality is a property of the 3D structure, so recognition also requires an appreciation of the conformation. In many situations, the bioactive conformation is undefined. We set out to address this by defining and using several novel 2D descriptors to capture general characteristic features of the chiral center. Using machine-learning methods, we built different predictive models to estimate if a chiral pair (a set of two enantiomers) might exhibit a chiral cliff in a binding assay. A set of about 3800 chiral pairs extracted from the ChEMBL23 database was used to train and test our models. By achieving an accuracy of up to 75 %, our models provide good performance in discriminating chiral cliffs from non-cliffs. More importantly, we were able to derive some simple guidelines for when one can reasonably use a racemate and when an enantiopure compound is needed in an assay. We critically discuss our results and show detailed examples of using our guidelines. Along with this publication we provide our dataset, our novel descriptors, and the Python code to rebuild the predictive models. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chirality transfer technique between liquid crystal microdroplets using microfluidic systems

Science.gov (United States)

Guo, Jin-kun; Lee, Doyeon; Song, Jang-kun

2018-02-01

Cholesteric liquid crystal (LC) microdroplet is applied in many areas, such as tunable laser, biosensor, information display and security identification, due to its unique optical properties. The topological structure, defects, and photonic crystallinity in the cholesteric liquid crystal (LC) microdroplet can be controlled through the chirality. Here we report an interesting phenomenon that chirality information can be shared among dispersed LC microdroplets in surfactant aqueous solution, which is driven by the transferring of chiral dopant molecules. As a result, we developed an artificial molecule transfer technology which could in situ vary the material composition within the isolated dispersed microdroplets. The molecular transfer is switchable and the transfer speed is controllable by tuning the molecular solubility in continuous phase. Based on this technique, we manipulated, forward and backward, the topological evolution and the photonic crystal band-gap of the dispersed LC droplet. This technique is an easy and powerful experimental tool, and it may be applicable to other fields in optical application, biology, chemistry and material science.

ATLAS diboson excesses from the stealth doublet model

Directory of Open Access Journals (Sweden)

Wei Chao

2016-02-01

Full Text Available The ATLAS Collaboration has reported excesses in diboson invariant mass searches of new resonances around 2 TeV, which might be a prediction of new physics around that mass range. We interpret these results in the context of a modified stealth doublet model where the extra Higgs doublet has a Yukawa interaction with the first generation quarks, and show that the heavy CP-even Higgs boson can naturally explain the excesses in the WW and ZZ channels with a small Yukawa coupling, ξ∼0.15, and a tiny mixing angle with the SM Higgs boson, α∼0.05. Furthermore, the model satisfies constraints from colliders and electroweak precision measurements.

Separation of carbon nanotubes into chirally enriched fractions

Science.gov (United States)

Doorn, Stephen K [Los Alamos, NM; Niyogi, Sandip [Los Alamos, NM

2012-04-10

A mixture of single-walled carbon nanotubes ("SWNTs") is separated into fractions of enriched chirality by preparing an aqueous suspension of a mixture of SWNTs and a surfactant, injecting a portion of the suspension on a column of separation medium having a density gradient, and centrifuging the column. In some embodiments, salt is added prior to centrifugation. In other embodiments, the centrifugation is performed at a temperature below room temperature. Fractions separate as colored bands in the column. The diameter of the separated SWNTs decreases with increasing density along the gradient of the column. The colored bands can be withdrawn separately from the column.

Thermal chiral vortical and magnetic waves: New excitation modes in chiral fluids

Energy Technology Data Exchange (ETDEWEB)

Kalaydzhyan, Tigran, E-mail: tigran@caltech.edu [Department of Physics, University of Illinois, 845 W Taylor Street, Chicago, IL 60607 (United States); Jet Propulsion Laboratory, 4800 Oak Grove Dr, M/S 298, Pasadena, CA 91109 (United States); Murchikova, Elena [TAPIR, California Institute of Technology, MC 350-17, Pasadena, CA 91125 (United States)

2017-06-15

In certain circumstances, chiral (parity-violating) medium can be described hydrodynamically as a chiral fluid with microscopic quantum anomalies. Possible examples of such systems include strongly coupled quark–gluon plasma, liquid helium {sup 3}He-A, neutron stars and the Early Universe. We study first-order hydrodynamics of a chiral fluid on a vortex background and in an external magnetic field. We show that there are two previously undiscovered modes describing heat waves propagating along the vortex and magnetic field. We call them the Thermal Chiral Vortical Wave and Thermal Chiral Magnetic Wave. We also identify known gapless excitations of density (chiral vortical and chiral magnetic waves) and transverse velocity (chiral Alfvén wave). We demonstrate that the velocity of the chiral vortical wave is zero, when the full hydrodynamic framework is applied, and hence the wave is absent and the excitation reduces to the charge diffusion mode. We also comment on the frame-dependent contributions to the obtained propagation velocities.

Thermal chiral vortical and magnetic waves: New excitation modes in chiral fluids

International Nuclear Information System (INIS)

Kalaydzhyan, Tigran; Murchikova, Elena

2017-01-01

In certain circumstances, chiral (parity-violating) medium can be described hydrodynamically as a chiral fluid with microscopic quantum anomalies. Possible examples of such systems include strongly coupled quark–gluon plasma, liquid helium "3He-A, neutron stars and the Early Universe. We study first-order hydrodynamics of a chiral fluid on a vortex background and in an external magnetic field. We show that there are two previously undiscovered modes describing heat waves propagating along the vortex and magnetic field. We call them the Thermal Chiral Vortical Wave and Thermal Chiral Magnetic Wave. We also identify known gapless excitations of density (chiral vortical and chiral magnetic waves) and transverse velocity (chiral Alfvén wave). We demonstrate that the velocity of the chiral vortical wave is zero, when the full hydrodynamic framework is applied, and hence the wave is absent and the excitation reduces to the charge diffusion mode. We also comment on the frame-dependent contributions to the obtained propagation velocities.

Thermal chiral vortical and magnetic waves: New excitation modes in chiral fluids

Directory of Open Access Journals (Sweden)

Tigran Kalaydzhyan

2017-06-01

Full Text Available In certain circumstances, chiral (parity-violating medium can be described hydrodynamically as a chiral fluid with microscopic quantum anomalies. Possible examples of such systems include strongly coupled quark–gluon plasma, liquid helium 3He-A, neutron stars and the Early Universe. We study first-order hydrodynamics of a chiral fluid on a vortex background and in an external magnetic field. We show that there are two previously undiscovered modes describing heat waves propagating along the vortex and magnetic field. We call them the Thermal Chiral Vortical Wave and Thermal Chiral Magnetic Wave. We also identify known gapless excitations of density (chiral vortical and chiral magnetic waves and transverse velocity (chiral Alfvén wave. We demonstrate that the velocity of the chiral vortical wave is zero, when the full hydrodynamic framework is applied, and hence the wave is absent and the excitation reduces to the charge diffusion mode. We also comment on the frame-dependent contributions to the obtained propagation velocities.

Multi-Higgs doublet models: physical parametrization, sum rules and unitarity bounds

Science.gov (United States)

Bento, Miguel P.; Haber, Howard E.; Romão, J. C.; Silva, João P.

2017-11-01

If the scalar sector of the Standard Model is non-minimal, one might expect multiple generations of the hypercharge-1/2 scalar doublet analogous to the generational structure of the fermions. In this work, we examine the structure of a Higgs sector consisting of N Higgs doublets (where N ≥ 2). It is particularly convenient to work in the so-called charged Higgs basis, in which the neutral Higgs vacuum expectation value resides entirely in the first Higgs doublet, and the charged components of remaining N - 1 Higgs doublets are mass-eigenstate fields. We elucidate the interactions of the gauge bosons with the physical Higgs scalars and the Goldstone bosons and show that they are determined by an N × 2 N matrix. This matrix depends on ( N - 1)(2 N - 1) real parameters that are associated with the mixing of the neutral Higgs fields in the charged Higgs basis. Among these parameters, N - 1 are unphysical (and can be removed by rephasing the physical charged Higgs fields), and the remaining 2( N - 1)2 parameters are physical. We also demonstrate a particularly simple form for the cubic interaction and some of the quartic interactions of the Goldstone bosons with the physical Higgs scalars. These results are applied in the derivation of Higgs coupling sum rules and tree-level unitarity bounds that restrict the size of the quartic scalar couplings. In particular, new applications to three Higgs doublet models with an order-4 CP symmetry and with a Z_3 symmetry, respectively, are presented.

The derivative expansion of the fermion number current

International Nuclear Information System (INIS)

D'Hoker, E.; Goldstone, J.

1985-01-01

The fermion number current is evaluated to leading order in the derivative expansion for chiral fermions in the background of arbitrary Higgs and chiral gauge fields. This current is given by the gauged topological current plus a total divergence term. The total divergence term is absent in Weinberg-Salam theory with one scalar Higgs doublet, even for an arbitrary mass matrix, but appears when several Higgs doublets are present. (orig.)

Non-uniform chiral phase in effective chiral quark models

International Nuclear Information System (INIS)

Sadzikowski, M.; Broniowski, W.

2000-01-01

We analyze the phase diagram in effective chiral quark models (the Nambu-Jona-Lasinio model, the σ-model with quarks) and show that at the mean-field level a phase with a periodically-modulated chiral fields separates the usual phases with broken and restored chiral symmetry. A possible signal of such a phase is the production of multipion jets travelling in opposite directions, with individual pions having momenta of the order of several hundred MeV. This signal can be interpreted in terms of disoriented chiral condensates. (author)

A search for close-mass lepton doublet

International Nuclear Information System (INIS)

Riles, J.K.

1989-04-01

Described is a search for a heavy charged lepton with an associated neutrino of nearly the same mass, together known as a close-mass lepton doublet. The search is conducted in e + e/sup/minus// annihilation data taken with the Mark II detector at a center-of-mass energy of 29 GeV. In order to suppress contamination from conventional two-photon reactions, the search applies a novel, radiative-tagging technique. Requiring the presence of an isolated, energetic photon allows exploration for lepton doublets with a mass splitting smaller than that previously accessible to experiment. No evidence for such a new lepton has been found, enabling limits to be placed on allowed mass combinations. Mass differences as low as 250-300 MeV are excluded for charged lepton masses up to 10 GeV. 78 refs., 64 figs., 8 tabs

Insight into the chiral induction in supramolecular stacks through preferential chiral salvation

NARCIS (Netherlands)

George, S.J.; Tomovic, Z.; Schenning, A.P.H.J.; Meijer, E.W.

2011-01-01

Preferred handedness in the supramolecular chirality of self-assembled achiral oligo(p-phenylenevinylene) (OPV) derivatives is induced by chiral solvents and spectroscopic probing provides insight into the mechanistic aspects of this chiral induction through chiral solvation

The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice

International Nuclear Information System (INIS)

Gerhold, Philipp; Kallarackal, Jim; Humboldt-Universitaet, Berlin; Jansen, Karl

2011-11-01

The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self coupling. (orig.)

Autoamplification of molecular chirality through the induction of supramolecular chirality

NARCIS (Netherlands)

van Dijken, Derk Jan; Beierle, John M.; Stuart, Marc C. A.; Szymanski, Wiktor; Browne, Wesley R.; Feringa, Ben L.

2014-01-01

The novel concept for the autoamplification of molecular chirality, wherein the amplification proceeds through the induction of supramolecular chirality, is presented. A solution of prochiral, ring-open diarylethenes is doped with a small amount of their chiral, ring-closed counterpart. The

Active chiral fluids.

Science.gov (United States)

Fürthauer, S; Strempel, M; Grill, S W; Jülicher, F

2012-09-01

Active processes in biological systems often exhibit chiral asymmetries. Examples are the chirality of cytoskeletal filaments which interact with motor proteins, the chirality of the beat of cilia and flagella as well as the helical trajectories of many biological microswimmers. Here, we derive constitutive material equations for active fluids which account for the effects of active chiral processes. We identify active contributions to the antisymmetric part of the stress as well as active angular momentum fluxes. We discuss four types of elementary chiral motors and their effects on a surrounding fluid. We show that large-scale chiral flows can result from the collective behavior of such motors even in cases where isolated motors do not create a hydrodynamic far field.

Acylation of Chiral Alcohols: A Simple Procedure for Chiral GC Analysis

Directory of Open Access Journals (Sweden)

Mireia Oromí-Farrús

2012-01-01

Full Text Available The use of iodine as a catalyst and either acetic or trifluoroacetic acid as a derivatizing reagent for determining the enantiomeric composition of acyclic and cyclic aliphatic chiral alcohols was investigated. Optimal conditions were selected according to the molar ratio of alcohol to acid, the reaction time, and the reaction temperature. Afterwards, chiral stability of chiral carbons was studied. Although no isomerization was observed when acetic acid was used, partial isomerization was detected with the trifluoroacetic acid. A series of chiral alcohols of a widely varying structural type were then derivatized with acetic acid using the optimal conditions. The resolution of the enantiomeric esters and the free chiral alcohols was measured using a capillary gas chromatograph equipped with a CP Chirasil-DEX CB column. The best resolutions were obtained with 2-pentyl acetates (α=3.00 and 2-hexyl acetates (α=1.95. This method provides a very simple and efficient experimental workup procedure for analyzing chiral alcohols by chiral-phase GC.

Acylation of Chiral Alcohols: A Simple Procedure for Chiral GC Analysis.

Science.gov (United States)

Oromí-Farrús, Mireia; Torres, Mercè; Canela, Ramon

2012-01-01

The use of iodine as a catalyst and either acetic or trifluoroacetic acid as a derivatizing reagent for determining the enantiomeric composition of acyclic and cyclic aliphatic chiral alcohols was investigated. Optimal conditions were selected according to the molar ratio of alcohol to acid, the reaction time, and the reaction temperature. Afterwards, chiral stability of chiral carbons was studied. Although no isomerization was observed when acetic acid was used, partial isomerization was detected with the trifluoroacetic acid. A series of chiral alcohols of a widely varying structural type were then derivatized with acetic acid using the optimal conditions. The resolution of the enantiomeric esters and the free chiral alcohols was measured using a capillary gas chromatograph equipped with a CP Chirasil-DEX CB column. The best resolutions were obtained with 2-pentyl acetates (α = 3.00) and 2-hexyl acetates (α = 1.95). This method provides a very simple and efficient experimental workup procedure for analyzing chiral alcohols by chiral-phase GC.

Doublet III neutral beam multi-stream command language system

International Nuclear Information System (INIS)

Campbell, L.; Garcia, J.R.

1983-12-01

A multi-stream command language system was developed to provide control of the dual source neutral beam injectors on the Doublet III experiment at GA Technologies Inc. The Neutral Beam command language system consists of three parts: compiler, sequencer, and interactive task. The command language, which was derived from the Doublet III tokamak command language, POPS, is compiled, using a recursive descent compiler, into reverse polish notation instructions which then can be executed by the sequencer task. The interactive task accepts operator commands via a keyboard. The interactive task directs the operation of three input streams, creating commands which are then executed by the sequencer. The streams correspond to the two sources within a Doublet III neutral beam, plus an interactive stream. The sequencer multiplexes the execution of instructions from these three streams. The instructions include reads and writes to an operator terminal, arithmetic computations, intrinsic functions such as CAMAC input and output, and logical instructions. The neutral beam command language system was implemented using Modular Computer Systems (ModComp) Pascal and consists of two tasks running on a ModComp Classic IV computer

Titanium gettering in Doublet III

International Nuclear Information System (INIS)

de Grassie, J.S.; Callis, R.; Campbell, G.

1980-08-01

The application of mild titanium gettering in the Doublet III tokamak has led to a significant improvement in the obtainable operating regimes and discharge parameters for all of the many plasma cross-sectional shapes studied. With gettering, low-Z impurities and radiated power are greatly reduced. The maximum line averaged electron density has increased 50% (anti n/sub e max/ approx. 1 x 10 20 /m 3 ), corresponding to a Murakami coefficient of nearly 6

Fractional Quantum Hall Effect in n = 0 Landau Band of Graphene with Chern Number Matrix

Science.gov (United States)

Kudo, Koji; Hatsugai, Yasuhiro

2018-06-01

Fully taking into account the honeycomb lattice structure, fractional quantum Hall states of graphene are considered by a pseudopotential projected into the n = 0 Landau band. By using chirality as an internal degree of freedom, the Chern number matrices are defined and evaluated numerically. Quantum phase transition induced by changing a range of the interaction is demonstrated that is associated with chirality ferromagnetism. The chirality-unpolarized ground state is consistent with the Halperin 331 state of the bilayer quantum Hall system.

Physiological consequences of doublet discharges on motoneuronal firing and motor unit force

Directory of Open Access Journals (Sweden)

Włodzimierz eMrówczyński

2015-03-01

Full Text Available The double discharges are observed at the onset of contractions of mammalian motor units (MUs, especially during their recruitment to strong or fast movements. Doublets lead to MU force increase and improve ability of muscles to maintain high force during prolonged contractions. In this review we discuss an ability to produce doublets by fast and slow motoneurons (MNs, their influence on the course of action potential afterhyperpolarization as well as its role in modulation of the initial stage of the firing pattern of MNs. In conclusion, a generation of doublets is an important strategy of motor control, responsible for fitting the motoneuronal firing rate to the optimal for MUs at the start of their contraction, necessary for increment of muscle force.

On chirality transfer in electron donor-acceptor complexes. A prediction for the sulfinimine···BF3 system.

Science.gov (United States)

Rode, Joanna E; Dobrowolski, Jan Cz

2012-01-01

Stabilization energies of the electron donor-acceptor sulfinimine···BF(3) complexes calculated at either the B3LYP/aug-cc-pVTZ or the MP2/aug-cc-pVTZ level do not allow to judge, whether the N- or O-atom in sulfinimine is stronger electron-donor to BF(3) . The problem seems to be solvable because chirality transfer phenomenon between chiral sulfinimine and achiral BF(3) is expected to be vibrational circular dichroism (VCD) active. Moreover, the bands associated with the achiral BF(3) molecule are predicted to be the most intense in the entire spectrum. However, the VCD band robustness analyses show that most of the chirality transfer modes of BF(3) are unreliable. Conversely, variation of VCD intensity with change of intermolecular distance, angle, and selected dihedrals between the complex partners shows that to establish the robustness of chirality transfer mode. It is also necessary to determine the influence of the potential energy surface (PES) shape on the VCD intensity. At the moment, there is still no universal criterion for the chirality transfer mode robustness and the conclusions formulated based on one system cannot be directly transferred even to a quite similar one. However, it is certain that more attention should be focused on relation of PES shape and the VCD mode robustness problem. Copyright © 2011 Wiley Periodicals, Inc.

Enantioselectively controlled release of chiral drug (metoprolol) using chiral mesoporous silica materials

Energy Technology Data Exchange (ETDEWEB)

Guo Zhen; Liu Xianbin; Ng, Siu-Choon; Chen Yuan; Yang Yanhui [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459 (Singapore); Du Yu, E-mail: du_yu@jlu.edu.cn, E-mail: yhyang@ntu.edu.sg [College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

2010-04-23

Chiral porous materials have attracted burgeoning attention on account of their potential applications in many areas, such as enantioseparation, chiral catalysis, chemical sensors and drug delivery. In this report, chiral mesoporous silica (CMS) materials with various pore sizes and structures were prepared using conventional achiral templates (other than chiral surfactant) and a chiral cobalt complex as co-template. The synthesized CMS materials were characterized by x-ray diffraction, nitrogen physisorption, scanning electron microscope and transmission electron microscope. These CMS materials, as carriers, were demonstrated to be able to control the enantioselective release of a representative chiral drug (metoprolol). The release kinetics, as modeled by the power law equation, suggested that the release profiles of metoprolol were remarkably dependent on the pore diameter and pore structure of CMS materials. More importantly, R- and S-enantiomers of metoprolol exhibited different release kinetics on CMS compared to the corresponding achiral mesoporous silica (ACMS), attributable to the existence of local chirality on the pore wall surface of CMS materials. The chirality of CMS materials on a molecular level was further substantiated by vibrational circular dichroism measurements.

Enantioselectively controlled release of chiral drug (metoprolol) using chiral mesoporous silica materials

International Nuclear Information System (INIS)

Guo Zhen; Liu Xianbin; Ng, Siu-Choon; Chen Yuan; Yang Yanhui; Du Yu

2010-01-01

Chiral porous materials have attracted burgeoning attention on account of their potential applications in many areas, such as enantioseparation, chiral catalysis, chemical sensors and drug delivery. In this report, chiral mesoporous silica (CMS) materials with various pore sizes and structures were prepared using conventional achiral templates (other than chiral surfactant) and a chiral cobalt complex as co-template. The synthesized CMS materials were characterized by x-ray diffraction, nitrogen physisorption, scanning electron microscope and transmission electron microscope. These CMS materials, as carriers, were demonstrated to be able to control the enantioselective release of a representative chiral drug (metoprolol). The release kinetics, as modeled by the power law equation, suggested that the release profiles of metoprolol were remarkably dependent on the pore diameter and pore structure of CMS materials. More importantly, R- and S-enantiomers of metoprolol exhibited different release kinetics on CMS compared to the corresponding achiral mesoporous silica (ACMS), attributable to the existence of local chirality on the pore wall surface of CMS materials. The chirality of CMS materials on a molecular level was further substantiated by vibrational circular dichroism measurements.

Chiral discotics; expression and amplification of chirality

NARCIS (Netherlands)

Brunsveld, L.; Meijer, E.W.; Rowan, A.E.; Nolte, R.J.M.; Denmark, S.E.; Nolte, R.J.M.; Meijer, E.W.

2003-01-01

In this contribution, chirality and discotic liquid crystals are discussed as a tool for studying the self-assembly of these molecules, both in solution and in the solid state. Therefore, the objective of this chapter is to summarize and elucidate how molecular chirality can be expressed in discotic

The inert doublet model: a new archetype of WIMP dark matter?

International Nuclear Information System (INIS)

Tytgat, M Hg

2008-01-01

The Inert Doublet Model (IDM) is a two doublet extension of the Higgs-Brout-Englert sector of the Standard Model with a Z2 symmetry in order to prevent FCNC. If the Z2 symmetry is not spontaneously broken, the lightest neutral extra scalar is a dark matter candidate. We briefly review the phenomenology of the model, emphasizing its relevance for the issue of Electroweak Symmetry Breaking (EWSB) and the prospects for detection of dark matter

Static and dynamical anomalies caused by chiral soliton lattice in molecular-based chiral magnets

International Nuclear Information System (INIS)

Kishine, Jun-ichiro; Inoue, Katsuya; Kikuchi, Koichi

2007-01-01

Interplay of crystallographic chirality and magnetic chirality has been of great interest in both chemist's and physicist's viewpoints. Crystals belonging to chiral space groups are eligible to stabilize macroscopic chiral magnetic order. This class of magnetic order is described by the chiral XY model, where the transverse magnetic field perpendicular to the chiral axis causes the chiral soliton lattice (CSL) formation. As a clear evidence of the chiral magnetic order, the temperature dependence of the transverse magnetization exhibits sharp cusp just below the mean field ferrimagnetic transition temperature, indicating the formation of the CSL. In addition to the static anomaly, we expect the CSL formation also causes dynamical anomalies such as induction of the spin supercurrent

Chiral supramolecular organization from a sheet-like achiral gel: a study of chiral photoinduction.

Science.gov (United States)

Royes, Jorge; Polo, Víctor; Uriel, Santiago; Oriol, Luis; Piñol, Milagros; Tejedor, Rosa M

2017-05-31

Chiral photoinduction in a photoresponsive gel based on an achiral 2D architecture with high geometric anisotropy and low roughness has been investigated. Circularly polarized light (CPL) was used as a chiral source and an azobenzene chromophore was employed as a chiral trigger. The chiral photoinduction was studied by evaluating the preferential excitation of enantiomeric conformers of the azobenzene units. Crystallographic data and density functional theory (DFT) calculations show how chirality is transferred to the achiral azomaterials as a result of the combination of chiral photochemistry and supramolecular interactions. This procedure could be applied to predict and estimate chirality transfer from a chiral physical source to a supramolecular organization using different light-responsive units.

Instability of the hedgehog shape for the octet baryon in the chiral quark soliton model

OpenAIRE

Akiyama, Satoru; Futami, Yasuhiko

2003-01-01

In this paper the stability of the hedgehog shape of the chiral soliton is studied for the octet baryon with the SU(3) chiral quark soliton model. The strangeness degrees of freedom are treated by a simplified bound-state approach, which omits the locality of the kaon wave function. The mean field approximation for the flavor rotation is applied to the model. The classical soliton changes shape according to the strangeness. The baryon appears as a rotational band of the combined system of the...

Chirality invariance and 'chiral' fields

International Nuclear Information System (INIS)

Ziino, G.

1978-01-01

The new field model derived in the present paper actually gives a definite answer to three fundamental questions concerning elementary-particle physics: 1) The phenomenological dualism between parity and chirality invariance: it would be only an apparent display of a general 'duality' principle underlying the intrinsic nature itself of (spin 1/2) fermions and expressed by the anticommutativity property between scalar and pseudoscalar charges. 2) The real physical meaning of V - A current structure: it would exclusively be connected to the one (just pointed out) of chiral fields themselves. 3) The unjustified apparent oddness shown by Nature in weak interactions, for the fact of picking out only one of the two (left- and right-handed) fermion 'chiral' projections: the key to such a 'mystery' would just be provided by the consequences of the dual and partial character of the two fermion-antifermion field bases. (Auth.)

Chiral measurements with the Fixed-Point Dirac operator and construction of chiral currents

International Nuclear Information System (INIS)

Hasenfratz, P.; Hauswirth, S.; Holland, K.; Joerg, T.; Niedermayer, F.

2002-01-01

In this preliminary study, we examine the chiral properties of the parametrized Fixed-Point Dirac operator D FP , see how to improve its chirality via the Overlap construction, measure the renormalized quark condensate Σ-circumflex and the topological susceptibility χ t , and investigate local chirality of near zero modes of the Dirac operator. We also give a general construction of chiral currents and densities for chiral lattice actions

Effects of chirality and surface stresses on the bending and buckling of chiral nanowires

International Nuclear Information System (INIS)

Wang, Jian-Shan; Shimada, Takahiro; Kitamura, Takayuki; Wang, Gang-Feng

2014-01-01

Due to their superior optical, elastic and electrical properties, chiral nanowires have many applications as sensors, probes, and building blocks of nanoelectromechanical systems. In this paper, we develop a refined Euler–Bernoulli beam model for chiral nanowires with surface effects and material chirality incorporated. This refined model is employed to investigate the bending and buckling of chiral nanowires. It is found that surface effects and material chirality significantly affect the elastic behaviour of chiral nanowires. This study is helpful not only for understanding the size-dependent behaviour of chiral nanowires, but also for characterizing their mechanical properties. (paper)

Influence of microemulsion chirality on chromatographic figures of merit in EKC: results with novel three-chiral-component microemulsions and comparison with one- and two-chiral-component microemulsions.

Science.gov (United States)

Kahle, Kimberly A; Foley, Joe P

2007-08-01

Novel microemulsion formulations containing all chiral components are described for the enantioseparation of six pairs of pharmaceutical enantiomers (atenolol, ephedrine, metoprolol, N-methyl ephedrine, pseudoephedrine, and synephrine). The chiral surfactant dodecoxycarbonylvaline (DDCV, R- and S-), the chiral cosurfactant S-2-hexanol, and the chiral oil diethyl tartrate (R- and S-) were combined to create four different chiral microemulsions, three of which were stable. Results obtained for enantioselectivity, efficiency, and resolution were compared for the triple-chirality systems and the single-chirality system that contained chiral surfactant only. Improvements in enantioselectivity and resolution were achieved by simultaneously incorporating three chiral components into the aggregate. The one-chiral-component microemulsion provided better efficiencies. Enantioselective synergies were identified for the three-chiral-component nanodroplets using a thermodynamic model. Additionally, two types of dual-chirality systems, chiral surfactant/chiral cosurfactant and chiral surfactant/chiral oil, were examined in terms of chromatographic figures of merit, with the former providing much better resolution. The two varieties of two-chiral-component microemulsions gave similar values for enantioselectivity and efficiency. Lastly, the microemulsion formulations were divided into categories based on the number of chiral microemulsion reagents and the average results for each pair of enantiomers were analyzed for trends. In general, enantioselectivity and resolution were enhanced while efficiency was decreased as more chiral components were used to create the pseudostationary phase (PSP).

Chiral heat wave and mixing of magnetic, vortical and heat waves in chiral media

International Nuclear Information System (INIS)

Chernodub, M.N.

2016-01-01

We show that a hot rotating fluid of relativistic chiral fermions possesses a new gapless collective mode associated with coherent propagation of energy density and chiral density waves along the axis of rotation. This mode, which we call the Chiral Heat Wave, emerges due to a mixed gauge-gravitational anomaly. At finite density the Chiral Heat Wave couples to the Chiral Vortical Wave while in the presence of an external magnetic field it mixes with the Chiral Magnetic Wave. The coupling of the Chiral Magnetic and Chiral Vortical Waves is also demonstrated. We find that the coupled waves — which are coherent fluctuations of the vector, axial and energy currents — have generally different velocities compared to the velocities of the individual waves.

Enhanced nuclear magnetic resonance in a non-magnetic cubic doublet

International Nuclear Information System (INIS)

Veenendaal, E.J.

1982-01-01

In this thesis two lanthanide compounds are studied which show enhanced nuclear magnetism at low temperatures: Rb 2 NaHoF 6 and CsNaHoF 6 . Chapter II gives a description of the 4 He-circulating refrigerator, which was built to provide the low temperatures required for the polarization of the enhanced nuclear moments. This type of dilution refrigerator was chosen because of its simple design and large cooling power. Chapter III is devoted to a comparison of the different types of dilution refrigerators. A theoretical discussion is given of their performance, starting from the differential equations, which govern the temperature distribution in the refrigerator. In chapter IV the actual performance of the refrigerator, described in chapter II is discussed. In chapter V a description of the NMR-apparatus, developed for very-low-temperature NMR experiments is given. In chapter VI experimental results on the compound Rb 2 NaHoF 6 are presented. The CEF-ground state of this compound is probably the non-magnetic doublet GAMMA 3 , but at a temperature of 170 K a structural phase transition lowers the crystal symmetry from cubic to tetragonal and the doublet is split into two singlets. In chapter VII specific heat, (enhanced) nuclear magnetic resonance and magnetization measurements on the compound Cs 2 NaHoF 6 are presented which also has a GAMMA 3 -doublet ground state. In zero magnetic field the degeneracy of the doublet is removed at a temperature of 393 mK, where a phase transition is induced by quadrupolar interactions. (Auth.)

Scalar dark matter in leptophilic two-Higgs-doublet model

Science.gov (United States)

Bandyopadhyay, Priyotosh; Chun, Eung Jin; Mandal, Rusa

2018-04-01

Two-Higgs-Doublet Model of Type-X in the large tan ⁡ β limit becomes leptophilic to allow a light pseudo-scalar A and thus provides an explanation of the muon g - 2 anomaly. Introducing a singlet scalar dark matter S in this context, one finds that two important dark matter properties, nucleonic scattering and self-annihilation, are featured separately by individual couplings of dark matter to the two Higgs doublets. While one of the two couplings is strongly constrained by direct detection experiments, the other remains free to be adjusted for the relic density mainly through the process SS → AA. This leads to the 4τ final states which can be probed by galactic gamma ray detections.

THE Na 8200 Å DOUBLET AS AN AGE INDICATOR IN LOW-MASS STARS

International Nuclear Information System (INIS)

Schlieder, Joshua E.; Simon, Michal; Lépine, Sébastien; Rice, Emily; Fielding, Drummond; Tomasino, Rachael

2012-01-01

We investigate the use of the gravity sensitive neutral sodium (Na I) doublet at 8183 Å and 8195 Å (Na 8200 Å doublet) as an age indicator for M dwarfs. We measured the Na doublet equivalent width (EW) in giants, old dwarfs, young dwarfs, and candidate members of the β Pic moving group using medium-resolution spectra. Our Na 8200 Å doublet EW analysis shows that the feature is useful as an approximate age indicator in M-type dwarfs with (V – K s ) ≥ 5.0, reliably distinguishing stars older and younger than 100 Myr. A simple derivation of the dependence of the Na EW on temperature and gravity supports the observational results. An analysis of the effects of metallicity shows that this youth indicator is best used on samples with similar metallicity. The age estimation technique presented here becomes useful in a mass regime where traditional youth indicators are increasingly less reliable, is applicable to other alkali lines, and will help identify new low-mass members in other young clusters and associations.

Chiral Induction with Chiral Conformational Switches in the Limit of Low "Sergeants to Soldiers" Ratio

DEFF Research Database (Denmark)

Nuermaimaiti, Ajiguli; Bombis, Christian; Knudsen, Martin Markvard

2014-01-01

Molecular-level insights into chiral adsorption phenomena are highly relevant within the fields of asymmetric heterogeneous catalysis or chiral separation and may contribute to understand the origins of homochirality in nature. Here, we investigate chiral induction by the "sergeants and soldiers......" mechanism for an oligo(phenylene ethynylene) based chiral conformational switch by coadsorbing it with an intrinsically chiral seed on Au(111). Through statistical analysis of scanning tunneling microscopy (STM) data we demonstrate successful chiral induction with a very low concentration of seeding...... molecules down to 3%. The microscopic mechanism for the observed chiral induction is suggested to involve nucleation of the intrinsically chiral seeds, allowing for effective transfer and amplification of chirality to large numbers of soldier target molecules....

Higgs boson couplings in multi-doublet models with natural flavour conservation

Directory of Open Access Journals (Sweden)

Kei Yagyu

2016-12-01

Full Text Available We investigate the deviation in the couplings of the standard model (SM like Higgs boson (h with a mass of 125 GeV from the prediction of the SM in multi-doublet models within the framework where flavour changing neutral currents at the tree level are naturally forbidden. After we present the general expressions for the modified gauge and Yukawa couplings for h, we show the correlation between the deviation in the Yukawa coupling for the tau lepton hτ+τ− and that for the bottom quark hbb¯ under the assumption of a non-zero deviation in the hVV (V=W,Z couplings in two Higgs doublet models (2HDMs and three Higgs doublet models (3HDMs as simple examples. We clarify the possible allowed prediction of the deviations in the 3HDMs which cannot be explained in the 2HDMs even taking into account the one-loop electroweak corrections to the Yukawa coupling.

The half-skyrmion phase in a chiral-quark model

International Nuclear Information System (INIS)

Mantovani Sarti, Valentina; Vento, Vicente

2014-01-01

The Chiral Dilaton Model, where baryons arise as non-topological solitons built from the interaction of quarks and chiral mesons, shows in the high density low temperature regime a two phase scenario in the nuclear matter phase diagram. Dense soliton matter described by the Wigner–Seitz approximation generates a periodic potential in terms of the sigma and pion fields that leads to the formation of a band structure. The analysis up to three times nuclear matter density shows that soliton matter undergoes two separate phase transitions: a delocalization of the baryon number density leading to B=1/2 structures, as in skyrmion matter, at moderate densities, and quark deconfinement at larger densities. This description fits well into the so-called quarkyonic phase where, before deconfinement, nuclear matter should undergo structural changes involving the restoration of fundamental symmetries of QCD

Scalable UWB photonic generator based on the combination of doublet pulses.

Science.gov (United States)

Moreno, Vanessa; Rius, Manuel; Mora, José; Muriel, Miguel A; Capmany, José

2014-06-30

We propose and experimentally demonstrate a scalable and reconfigurable optical scheme to generate high order UWB pulses. Firstly, various ultra wideband doublets are created through a process of phase-to-intensity conversion by means of a phase modulation and a dispersive media. In a second stage, doublets are combined in an optical processing unit that allows the reconfiguration of UWB high order pulses. Experimental results both in time and frequency domains are presented showing good performance related to the fractional bandwidth and spectral efficiency parameters.

Chiral Dynamics 2006

Science.gov (United States)

Ahmed, Mohammad W.; Gao, Haiyan; Weller, Henry R.; Holstein, Barry

2007-10-01

effects in hyperon semileptonic decays from lattice QCD / S. Simula. Uncertainty bands for chiral extrapolations / B.U. Musch. Update of the nucleon electromagnetic form factors / C. B. Crawford. N and N to ? transition from factors from lattice QCD / C. Alexandrou. The [equation] transition at low Q2 and the pionic contribution / S. Stave. Strange Quark CoNtributions to the form factors of the nucleon / F. Benmokhtar. Dynamical polarizabilities of the nucleon / B. Pasquini. Hadron magnetic moments and polarizabilities in lattice QCD / F.X. Lee. Spin-dependent compton scattering from 3He and the neutron spin polarizabilities / H. Gao. Chiral dynamics from Dyson-Schwinger equations / C.D. Roberts. Radiative neutron [Beta symbol]-decay in effective field theory / S. Gardner. Comparison between different renormalization schemes for co-variant BChPT / T.A. Gail. Non-perturbative study of the light pseudoscalar masses in chiral dynamics / José Antonio Oller. Masses and widths of hadrons in nuclear matter / M. Kotulla. Chiral effective field theory at finite density / R.J. Furnstahl. The K-nuclear interaction: a search fro deeply bound K-nuclear clusters / P. Camerini. Moments of GPDs from lattice QCD / D.G. Richards. Generalized parton distributions in effective field theory / J.W. Chen. Near-threshold pion production: experimental update / M.W. Ahmed. Pion photoproduction near threshold theory update / L. Tiator.

Quenched chiral logarithms

International Nuclear Information System (INIS)

Sharpe, S.R.

1992-04-01

I develop a diagrammatic method for calculating chiral logarithms in the quenched approximation. While not rigorous, the method is based on physically reasonable assumptions, which can be tested by numerical simulations. The main results are that, at leading order in the chiral expansion, (a) there are no chiral logarithms in quenched f π m u = m d ; (b) the chiral logarithms in B K and related kaon B-parameters are, for m d = m s the same in the quenched approximation as in the full theory (c) for m π and the condensate, there are extra chiral logarithms due to loops containing the η', which lead to a peculiar non-analytic dependence of these quantities on the bare quark mass. Following the work of Gasser and Leutwyler, I discuss how there is a predictable finite volume dependence associated with each chiral logarithm. I compare the resulting predictions with numerical results: for most quantities the expected volume dependence is smaller than the errors. but for B V and B A there is an observed dependence which is consistent with the predictions

Nonlinear spectroscopic studies of chiral media

International Nuclear Information System (INIS)

Belkin, Mikhail Alexandrovich

2004-01-01

Molecular chirality plays an important role in chemistry, biology, and medicine. Traditional optical techniques for probing chirality, such as circular dichroism and Raman optical activity rely on electric-dipole forbidden transitions. As a result, their intrinsic low sensitivity limits their use to probe bulk chirality rather than chiral surfaces, monolayers or thin films often important for chemical or biological systems. Contrary to the traditional chirality probes, chiral signal in sum-frequency generation (SFG) is electric-dipole allowed both on chiral surface and in chiral bulk making it a much more promising tool for probing molecular chirality. SFG from a chiral medium was first proposed in 1965, but had never been experimentally confirmed until this thesis work was performed. This thesis describes a set of experiments successfully demonstrating that chiral SFG responses from chiral monolayers and liquids are observable. It shows that, with tunable inputs, SFG can be used as a sensitive spectroscopic tool to probe chirality in both electronic and vibrational resonances of chiral molecules. The monolayer sensitivity is feasible in both cases. It also discusses the relevant theoretical models explaining the origin and the strength of the chiral signal in vibrational and electronic SFG spectroscopies

Silver Films with Hierarchical Chirality.

Science.gov (United States)

Ma, Liguo; Cao, Yuanyuan; Duan, Yingying; Han, Lu; Che, Shunai

2017-07-17

Physical fabrication of chiral metallic films usually results in singular or large-sized chirality, restricting the optical asymmetric responses to long electromagnetic wavelengths. The chiral molecule-induced formation of silver films prepared chemically on a copper substrate through a redox reaction is presented. Three levels of chirality were identified: primary twisted nanoflakes with atomic crystal lattices, secondary helical stacking of these nanoflakes to form nanoplates, and tertiary micrometer-sized circinates consisting of chiral arranged nanoplates. The chiral Ag films exhibited multiple plasmonic absorption- and scattering-based optical activities at UV/Vis wavelengths based on their hierarchical chirality. The Ag films showed chiral selectivity for amino acids in catalytic electrochemical reactions, which originated from their primary atomic crystal lattices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Operator-generated command language for computer control of Doublet III

International Nuclear Information System (INIS)

Drobnis, D.; Petersen, P.

1982-02-01

The Control System for Doublet III consists of a medium-sized minicomputer system, with several keyboards and color alphanumeric CRTs for interactive operator interface to a large distributed CAMAC I/O system. Under normal operating conditions, however, all of the sequential and decision-making operations necessary to prepare each tokamak shot are performed directly by the computer, executing a set of Procedures coded in a convenient command language. Most of these Procedures have been developed by the Doublet III operators themselves, and are maintained, altered, and augmented as required without programmer attention. In effect, the Procedures have become a high-level tokamak Command Language

Doublet III: status and future plans

International Nuclear Information System (INIS)

Rawls, J.M.

1980-04-01

A synopsis is presented of the experimental results from the ohmic heating phase of Doublet III, with emphasis on the production of good target plasmas for the upcoming neutral beam injection phase. The program plan for the device over the life of the US-Japan cooperative program is discussed, as is the status of the preliminary investigation into replacing the present vacuum vessel by one better suited for ETF simulation

Classification of finite reparametrization symmetry groups in the three-Higgs-doublet model

International Nuclear Information System (INIS)

Ivanov, Igor P.; Vdovin, E.

2013-01-01

Symmetries play a crucial role in electroweak symmetry breaking models with non-minimal Higgs content. Within each class of these models, it is desirable to know which symmetry groups can be implemented via the scalar sector. In N-Higgs-doublet models, this classification problem was solved only for N=2 doublets. Very recently, we suggested a method to classify all realizable finite symmetry groups of Higgs-family transformations in the three-Higgs-doublet model (3HDM). Here, we present this classification in all detail together with an introduction to the theory of solvable groups, which play the key role in our derivation. We also consider generalized-CP symmetries, and discuss the interplay between Higgs-family symmetries and CP-conservation. In particular, we prove that presence of the Z 4 symmetry guarantees the explicit CP-conservation of the potential. This work completes classification of finite reparametrization symmetry groups in 3HDM. (orig.)

Induction of Chirality in Two-Dimensional Nanomaterials: Chiral 2D MoS2 Nanostructures.

Science.gov (United States)

Purcell-Milton, Finn; McKenna, Robert; Brennan, Lorcan J; Cullen, Conor P; Guillemeney, Lilian; Tepliakov, Nikita V; Baimuratov, Anvar S; Rukhlenko, Ivan D; Perova, Tatiana S; Duesberg, Georg S; Baranov, Alexander V; Fedorov, Anatoly V; Gun'ko, Yurii K

2018-02-27

Two-dimensional (2D) nanomaterials have been intensively investigated due to their interesting properties and range of potential applications. Although most research has focused on graphene, atomic layered transition metal dichalcogenides (TMDs) and particularly MoS 2 have gathered much deserved attention recently. Here, we report the induction of chirality into 2D chiral nanomaterials by carrying out liquid exfoliation of MoS 2 in the presence of chiral ligands (cysteine and penicillamine) in water. This processing resulted in exfoliated chiral 2D MoS 2 nanosheets showing strong circular dichroism signals, which were far past the onset of the original chiral ligand signals. Using theoretical modeling, we demonstrated that the chiral nature of MoS 2 nanosheets is related to the presence of chiral ligands causing preferential folding of the MoS 2 sheets. There was an excellent match between the theoretically calculated and experimental spectra. We believe that, due to their high aspect ratio planar morphology, chiral 2D nanomaterials could offer great opportunities for the development of chiroptical sensors, materials, and devices for valleytronics and other potential applications. In addition, chirality plays a key role in many chemical and biological systems, with chiral molecules and materials critical for the further development of biopharmaceuticals and fine chemicals, and this research therefore should have a strong impact on relevant areas of science and technology such as nanobiotechnology, nanomedicine, and nanotoxicology.

Structural analysis, electronic properties, and band gaps of a graphene nanoribbon: A new 2D materials

Science.gov (United States)

Dass, Devi

2018-03-01

Graphene nanoribbon (GNR), a new 2D carbon nanomaterial, has some unique features and special properties that offer a great potential for interconnect, nanoelectronic devices, optoelectronics, and nanophotonics. This paper reports the structural analysis, electronic properties, and band gaps of a GNR considering different chirality combinations obtained using the pz orbital tight binding model. In structural analysis, the analytical expressions for GNRs have been developed and verified using the simulation for the first time. It has been found that the total number of unit cells and carbon atoms within an overall unit cell and molecular structure of a GNR have been changed with the change in their chirality values which are similar to the values calculated using the developed analytical expressions thus validating both the simulation as well as analytical results. Further, the electronic band structures at different chirality values have been shown for the identification of metallic and semiconductor properties of a GNR. It has been concluded that all zigzag edge GNRs are metallic with very small band gaps range whereas all armchair GNRs show both the metallic and semiconductor nature with very small and high band gaps range. Again, the total number of subbands in each electronic band structure is equal to the total number of carbon atoms present in overall unit cell of the corresponding GNR. The semiconductors GNRs can be used as a channel material in field effect transistor suitable for advanced CMOS technology whereas the metallic GNRs could be used for interconnect.

Chiral ward-Takahashi identities at finite temperature and chiral phase transition in (2+1) dimensional chiral Gross-Neveu model

International Nuclear Information System (INIS)

Shen Kun; Qiu Zhongping

1993-01-01

Chiral Ward-Takahashi identities at finite temperature are derived in (2+1) dimensional chiral Gross-Neveu model. In terms of these identities, fermion mass generation and the mass spectra of bound states are investigate at finite temperature. Taking the fermion mass as an order parameter, the authors discuss the phase structure and chiral phase transition and obtain the critical temperature

Reference peak method for analysis of doublets in gamma-ray spectrometry used in neutron activation analysis

International Nuclear Information System (INIS)

Wasek, M.; Cichowlas, A.; Sterlinski, S.; Dybczynski, R.

2000-01-01

A simple algebraic method for the quantitative analysis of doublets in gamma-ray spectra from HPGe detectors is presented. The calculation algorithm is accomplished using the Microsoft Excel program. The method does not require any assumptions regarding the shape of the peaks in the spectrum. The possibilities of quantitative analysis of doublets of various intensity ration and separation of ots components are discussed in detail. The practical examples proved the usefulness the method also for the analysis of the closed doublets. (author)

THE Na 8200 Angstrom-Sign DOUBLET AS AN AGE INDICATOR IN LOW-MASS STARS

Energy Technology Data Exchange (ETDEWEB)

Schlieder, Joshua E.; Simon, Michal [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Lepine, Sebastien; Rice, Emily [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Fielding, Drummond [Department of Physics and Astronomy, Johns Hopkins University, 366 Bloomberg Center, 3400 North Charles Street, Baltimore, MD 21218 (United States); Tomasino, Rachael, E-mail: michal.simon@stonybrook.edu, E-mail: schlieder@mpia-hd.mpg.de, E-mail: lepine@amnh.org, E-mail: erice@amnh.org, E-mail: dfieldi1@jhu.edu, E-mail: tomas1r@cmich.edu [Department of Physics, Central Michigan University, Mount Pleasant, MI 48859 (United States)

2012-05-15

We investigate the use of the gravity sensitive neutral sodium (Na I) doublet at 8183 Angstrom-Sign and 8195 Angstrom-Sign (Na 8200 Angstrom-Sign doublet) as an age indicator for M dwarfs. We measured the Na doublet equivalent width (EW) in giants, old dwarfs, young dwarfs, and candidate members of the {beta} Pic moving group using medium-resolution spectra. Our Na 8200 A doublet EW analysis shows that the feature is useful as an approximate age indicator in M-type dwarfs with (V - K{sub s}) {>=} 5.0, reliably distinguishing stars older and younger than 100 Myr. A simple derivation of the dependence of the Na EW on temperature and gravity supports the observational results. An analysis of the effects of metallicity shows that this youth indicator is best used on samples with similar metallicity. The age estimation technique presented here becomes useful in a mass regime where traditional youth indicators are increasingly less reliable, is applicable to other alkali lines, and will help identify new low-mass members in other young clusters and associations.

Chirality: from QCD to condensed matter

International Nuclear Information System (INIS)

Kharzeev, D.

2015-01-01

This lecture is about chirality and consists of 4 parts. In the first part a general introduction of chirality is given and its implementation in nuclear and particle physics, in particular the chiral magnetic effect, as well as Chirality in quantum materials (CME, optoelectronics, photonics) are discussed. The 2nd lecture is about the chiral magnetic effect. The 3rd lecture deals with the chiral magnetic effect and hydrodynamics and the last part with chirality and light. (nowak)

Localized excitations in superconducting point contacts: probing the Andreev doublet

International Nuclear Information System (INIS)

Bretheau, L.

2013-01-01

The Josephson effect describes the coherent coupling between superconductors and the resulting supercurrent. Microscopically, it arises from the existence of discrete quasiparticle states, localized at the weak link, the Andreev bound states. They come in doublets in each conduction channel of the weak link, with energies symmetric about the Fermi energy and opposite supercurrents. Each Andreev doublet gives rise to four states: the ground state |-> and the excited state |+>, with even parity, and the excited odd states |↑> and |↓>. Is it possible to address and control Andreev doublets? This thesis describes two sets of experiments designed to answer this question using the most basic Josephson element, a one-atom contact between two superconducting electrodes. In a first experiment, we have observed and characterized the excited odd states |↑> and |↓>. As expected for a spin-degenerate system, they do not carry supercurrent. In this experiment the excitation was uncontrolled and resulted from trapping of spurious quasiparticles. We have measured the lifetime of the odd states: under some condition, it is found to exceed 100 μs. The second experiment is a photon-absorption spectroscopy of the Andreev doublet. It was performed by using a Josephson junction as an integrated on-chip microwave emitter and detector. The observed Andreev transitions correspond to excitation from the ground state |->to the excited even state |+>, and are well accounted for by our quantum model. This result opens the way to coherent manipulation of this two level system. The direct observation of the excited Andreev state, either by quasiparticle-injection or photon-absorption, strongly supports the mesoscopic theory of the Josephson effect. It shows that in addition to the phase difference, each channel of a Josephson weak link possesses an internal fermionic degree of freedom. It could be used to code information in a novel type of superconducting qubit. (author) [fr

Self-Assembling, Stable Photonic Bend-Gap Phases in Emulsions of Chiral Nematics with Isotropic Fluids

Science.gov (United States)

Huang, Chien-Yueh; Petschek, R. G.

1998-03-01

We investigate the possible mesophases in emulsions of chiral nematic liquid crystals with immiscible isotropic fluids and surfactants. The interactions between the orientational fields of the chiral nematics and the surfactant membranes together with the topological constraints affect stability of micellar geometries and produce a new phase diagram. We compare the free energies of various candidate phases. Appropriate, likely realizable conditions on the surfactant and the pitch of the liquid crystal result in thermodynamically stable blue-phase like phases for a relatively wide range of parameters. Processing such emulsions may result in materials with photonic band gaps.

Angular dependences of the luminescence and density of photon states in a chiral liquid crystal

Energy Technology Data Exchange (ETDEWEB)

Umanskii, B A; Blinov, L M; Palto, S P [A.V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow, Russian Federaion (Russian Federation)

2013-11-30

Luminescence spectra of a laser dye-doped chiral liquid crystal have been studied in a wide range of angles (up to 60°) to the axis of its helical structure using a semicylindrical quartz prism, which made it possible to observe the shift and evolution of the photonic band gap in response to changes in angle. Using measured spectra and numerical simulation, we calculated the spectral distributions of the density of photon states in such a cholesteric crystal for polarised and unpolarised light, which characterise its structure as that of a chiral one-dimensional photonic crystal. (optics of liquid crystals)

Product fine-structure resolved photodissociation dynamics: The A band of H2O

International Nuclear Information System (INIS)

Zhou, Linsen; Xie, Daiqian; Sun, Zhigang; Guo, Hua

2014-01-01

The photodissociation dynamics of H 2 O in its first absorption band is investigated on an accurate potential energy surface based on a large number of high-level ab initio points. Several ro-vibrational states of the parent molecule are considered. Different from most previous theoretical studies, the spin-orbit and Λ-doublet populations of the open-shell OH fragment are reported from full-dimensional wave packet calculations. The populations of the two spin-orbit manifolds are in most cases close to the statistical limit, but the Λ-doublet is dominated by the A ″ component, thanks largely to the fast in-plane dissociation of H 2 O(A ~1 A ′′ ). Comparisons with experimental data and a Franck-Condon model are generally very good, although some discrepancies exist

Electric dipole moments in two-Higgs-doublet models

Energy Technology Data Exchange (ETDEWEB)

Jung, Martin [Institut für Physik, Technische Universität Dortmund,Otto-Hahn-Str. 4, D-44221 Dortmund (Germany); Pich, Antonio [IFIC, Universitat de València - CSIC,Apt. Correos 22085, E-46071 València (Spain)

2014-04-10

Electric dipole moments are extremely sensitive probes for additional sources of CP violation in new physics models. Specifically, they have been argued in the past to exclude new CP-violating phases in two-Higgs-doublet models. Since recently models including such phases have been discussed widely, we revisit the available constraints in the presence of mechanisms which are typically invoked to evade flavour-changing neutral currents. To that aim, we start by assessing the necessary calculations on the hadronic, nuclear and atomic/molecular level, deriving expressions with conservative error estimates. Their phenomenological analysis in the context of two-Higgs-doublet models yields strong constraints, in some cases weakened by a cancellation mechanism among contributions from neutral scalars. While the corresponding parameter combinations do not yet have to be unnaturally small, the constraints are likely to preclude large effects in other CP-violating observables. Nevertheless, the generically expected contributions to electric dipole moments in this class of models lie within the projected sensitivity of the next-generation experiments.

Power systems for the Doublet III 2-MW ECH system

International Nuclear Information System (INIS)

Remsen, D.B. Jr.

1981-10-01

A system providing 5 second pulses at 60 GHz from ten 200 kW gyrotrons is being prepared for electron cyclotron heating experiments on Doublet III. The power supply for the gyrotron system is a power supply currently under construction by Universal Voltronics Corporation for the Doublet III neutral beam power supply, and is to have the option of reverse polarity (negative) to fill the needs of the system of ten gyrotons operating in parallel. The output of this power supply is 80 kV at 100A for 5 second pulses with good regulation. The output pulse rise and fall times and fault protection response time are all compatible with the gyrotron requirements

Chirality in adsorption on solid surfaces.

Science.gov (United States)

Zaera, Francisco

2017-12-07

In the present review we survey the main advances made in recent years on the understanding of chemical chirality at solid surfaces. Chirality is an important topic, made particularly relevant by the homochiral nature of the biochemistry of life on Earth, and many chiral chemical reactions involve solid surfaces. Here we start our discussion with a description of surface chirality and of the different ways that chirality can be bestowed on solid surfaces. We then expand on the studies carried out to date to understand the adsorption of chiral compounds at a molecular level. We summarize the work published on the adsorption of pure enantiomers, of enantiomeric mixtures, and of prochiral molecules on chiral and achiral model surfaces, especially on well-defined metal single crystals but also on other flat substrates such as highly ordered pyrolytic graphite. Several phenomena are identified, including surface reconstruction and chiral imprinting upon adsorption of chiral agents, and the enhancement or suppression of enantioselectivity seen in some cases upon adsorption of enantiomixtures of chiral compounds. The possibility of enhancing the enantiopurity of adsorbed layers upon the addition of chiral seeds and the so-called "sergeants and soldiers" phenomenon are presented. Examples are provided where the chiral behavior has been associated with either thermodynamic or kinetic driving forces. Two main approaches to the creation of enantioselective surface sites are discussed, namely, via the formation of supramolecular chiral ensembles made out of small chiral adsorbates, and by adsorption of more complex chiral molecules capable of providing suitable chiral environments for reactants by themselves, via the formation of individual adsorbate:modifier adducts on the surface. Finally, a discussion is offered on the additional effects generated by the presence of the liquid phase often required in practical applications such as enantioselective crystallization, chiral

Possible incorporation of a dee-shaped vacuum vessel in Doublet III

International Nuclear Information System (INIS)

Davis, L.; Rawls, J.M.

1979-11-01

The design of Doublet III allows relative straightforward incorporation of any of a number of possible dee-configuration vacuum vessels that can serve as relevant size tests of reactor regime devices. Configurations simulating those of JET, ETF and INTOR with plasma areas larger than TFTR can be attained with significant physics parameter results. Such modifications to Doublet III could be incorporated into planned upgrade activites with operations beginning in 1984, early enough to influence the designs of ETF and INTOR and test the scaling laws, poloidal coil system, and impurity control systems proposed for these ignition devices

Chiral-like tunneling of electrons in two-dimensional semiconductors with Rashba spin-orbit coupling.

Science.gov (United States)

Ang, Yee Sin; Ma, Zhongshui; Zhang, C

2014-01-21

The unusual tunneling effects of massless chiral fermions (mCF) and massive chiral fermions (MCF) in a single layer graphene and bilayer graphene represent some of the most bizarre quantum transport phenomena in condensed matter system. Here we show that in a two-dimensional semiconductor with Rashba spin-orbit coupling (R2DEG), the real-spin chiral-like tunneling of electrons at normal incidence simultaneously exhibits features of mCF and MCF. The parabolic branch of opposite spin in R2DEG crosses at a Dirac-like point and has a band turning point. These features generate transport properties not found in usual two-dimensional electron gas. Albeit its π Berry phase, electron backscattering is present in R2DEG. An electron mimics mCF if its energy is in the vicinity of the subband crossing point or it mimics MCF if its energy is near the subband minima.

Chirality in molecular collision dynamics

Science.gov (United States)

Lombardi, Andrea; Palazzetti, Federico

2018-02-01

Chirality is a phenomenon that permeates the natural world, with implications for atomic and molecular physics, for fundamental forces and for the mechanisms at the origin of the early evolution of life and biomolecular homochirality. The manifestations of chirality in chemistry and biochemistry are numerous, the striking ones being chiral recognition and asymmetric synthesis with important applications in molecular sciences and in industrial and pharmaceutical chemistry. Chiral discrimination phenomena, due to the existence of two enantiomeric forms, very well known in the case of interaction with light, but still nearly disregarded in molecular collision studies. Here we review some ideas and recent advances about the role of chirality in molecular collisions, designing and illustrating molecular beam experiments for the demonstration of chiral effects and suggesting a scenario for a stereo-directional origin of chiral selection.

Fluxionally chiral DMAP catalysts: kinetic resolution of axially chiral biaryl compounds.

Science.gov (United States)

Ma, Gaoyuan; Deng, Jun; Sibi, Mukund P

2014-10-27

Can organocatalysts that incorporate fluxional groups provide enhanced selectivity in asymmetric transformations? To address this issue, we have designed chiral 4-dimethylaminopyridine (DMAP) catalysts with fluxional chirality. These catalysts were found to be efficient in promoting the acylative kinetic resolution of secondary alcohols and axially chiral biaryl compounds with selectivity factors of up to 37 and 51, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photoexcitation circular dichroism in chiral molecules

Science.gov (United States)

Beaulieu, S.; Comby, A.; Descamps, D.; Fabre, B.; Garcia, G. A.; Géneaux, R.; Harvey, A. G.; Légaré, F.; Mašín, Z.; Nahon, L.; Ordonez, A. F.; Petit, S.; Pons, B.; Mairesse, Y.; Smirnova, O.; Blanchet, V.

2018-05-01

Chiral effects appear in a wide variety of natural phenomena and are of fundamental importance in science, from particle physics to metamaterials. The standard technique of chiral discrimination—photoabsorption circular dichroism—relies on the magnetic properties of a chiral medium and yields an extremely weak chiral response. Here, we propose and demonstrate an orders of magnitude more sensitive type of circular dichroism in neutral molecules: photoexcitation circular dichroism. This technique does not rely on weak magnetic effects, but takes advantage of the coherent helical motion of bound electrons excited by ultrashort circularly polarized light. It results in an ultrafast chiral response and the efficient excitation of a macroscopic chiral density in an initially isotropic ensemble of randomly oriented chiral molecules. We probe this excitation using linearly polarized laser pulses, without the aid of further chiral interactions. Our time-resolved study of vibronic chiral dynamics opens a way to the efficient initiation, control and monitoring of chiral chemical change in neutral molecules at the level of electrons.

Doublet III construction and engineering test

International Nuclear Information System (INIS)

Anon.

1979-01-01

Progress during FY-78 on the construction and operation of the Doublet III is reported. Detailed discussions about the installation and testing of various components and subsystems, including the B-coil, E-coil, F-coils and support structure, vacuum vessel, vacuum pumping system, limiter, thermal insulation blanket, control system, B-coil power system, E-coil power system, F-coil power system, and motor-generator, are presented. A brief review of the engineering test operation is given

Observation of chiral phonons

KAUST Repository

Zhu, Hanyu; Yi, Jun; Li, Ming-yang; Xiao, Jun; Zhang, Lifa; Yang, Chih-Wen; Kaindl, Robert A.; Li, Lain-Jong; Wang, Yuan; Zhang, Xiang

2018-01-01

Chirality reveals symmetry breaking of the fundamental interaction of elementary particles. In condensed matter, for example, the chirality of electrons governs many unconventional transport phenomena such as the quantum Hall effect. Here we show that phonons can exhibit intrinsic chirality in monolayer tungsten diselenide. The broken inversion symmetry of the lattice lifts the degeneracy of clockwise and counterclockwise phonon modes at the corners of the Brillouin zone. We identified the phonons by the intervalley transfer of holes through hole-phonon interactions during the indirect infrared absorption, and we confirmed their chirality by the infrared circular dichroism arising from pseudoangular momentum conservation. The chiral phonons are important for electron-phonon coupling in solids, phonon-driven topological states, and energy-efficient information processing.

Observation of chiral phonons

KAUST Repository

Zhu, Hanyu

2018-02-01

Chirality reveals symmetry breaking of the fundamental interaction of elementary particles. In condensed matter, for example, the chirality of electrons governs many unconventional transport phenomena such as the quantum Hall effect. Here we show that phonons can exhibit intrinsic chirality in monolayer tungsten diselenide. The broken inversion symmetry of the lattice lifts the degeneracy of clockwise and counterclockwise phonon modes at the corners of the Brillouin zone. We identified the phonons by the intervalley transfer of holes through hole-phonon interactions during the indirect infrared absorption, and we confirmed their chirality by the infrared circular dichroism arising from pseudoangular momentum conservation. The chiral phonons are important for electron-phonon coupling in solids, phonon-driven topological states, and energy-efficient information processing.

Selection of doublet cellular patterns in directional solidification through spatially periodic perturbations

International Nuclear Information System (INIS)

Losert, W.; Stillman, D.A.; Cummins, H.Z.; Kopczynski, P.; Rappel, W.; Karma, A.

1998-01-01

Pattern formation at the solid-liquid interface of a growing crystal was studied in directional solidification using a perturbation technique. We analyzed both experimentally and numerically the stability range and dynamical selection of cellular arrays of 'doublets' with asymmetric tip shapes, separated by alternate deep and shallow grooves. Applying an initial periodic perturbation of arbitrary wavelength to the unstable planar interface allowed us to force the interface to evolve into doublet states that would not otherwise be dynamically accessible from a planar interface. We determined systematically the ranges of wavelength corresponding to stable singlets, stable doublets, and transient unstable patterns. Experimentally, this was accomplished by applying a brief UV light pulse of a desired spatial periodicity to the planar interface during the planar-cellular transient using the model alloy Succinonitrile-Coumarin 152. Numerical simulations of the nonlinear evolution of the interface were performed starting from a small sinusoidal perturbation of the steady-state planar interface. These simulations were carried out using a computationally efficient phase-field symmetric model of directional solidification with recently reformulated asymptotics and vanishing kinetics [A. Karma and W.-J. Rappel, Phys. Rev. E 53 R3017 (1996); Phys. Rev. Lett. 77, 4050 (1996); Phys. Rev. E 57, 4323 (1998)], which allowed us to simulate spatially extended arrays that can be meaningfully compared to experiments. Simulations and experiments show remarkable qualitative agreement in the dynamic evolution, steady-state structure, and instability mechanisms of doublet cellular arrays. copyright 1998 The American Physical Society

Inert doublet dark matter with an additional scalar singlet and 125 GeV Higgs boson

Energy Technology Data Exchange (ETDEWEB)

Dutta Banik, Amit; Majumdar, Debasish [Saha Institute of Nuclear Physics, Astroparticle Physics and Cosmology Division, Kolkata (India)

2014-11-15

In this work we consider a model for particle dark matter where an extra inert Higgs doublet and an additional scalar singlet is added to the Standard Model (SM) Lagrangian. The dark matter candidate is obtained from only the inert doublet. The stability of this one component dark matter is ensured by imposing a Z{sub 2} symmetry on this additional inert doublet. The additional singlet scalar has a vacuum expectation value (VEV) and mixes with the Standard Model Higgs doublet, resulting in two CP even scalars h{sub 1} and h{sub 2}. We treat one of these scalars, h{sub 1}, to be consistent with the SM Higgs-like boson of mass around 125 GeV reported by the LHC experiment. These two CP even scalars contribute to the annihilation cross section of this inert doublet dark matter, resulting in a larger dark matter mass region that satisfies the observed relic density. We also investigate the h{sub 1} → γγ and h{sub 1} → γ Z processes and compared these with LHC results. This is also used to constrain the dark matter parameter space in the present model. We find that the dark matter candidate in the mass region 60-80 GeV (m{sub 1} = 125 GeV, mass of h{sub 1}) satisfies the recent bound from LUX direct detection experiment. (orig.)

Chirality-controlled crystallization via screw dislocations.

Science.gov (United States)

Sung, Baeckkyoung; de la Cotte, Alexis; Grelet, Eric

2018-04-11

Chirality plays an important role in science from enantiomeric separation in chemistry to chiral plasmonics in nanotechnology. However, the understanding of chirality amplification from chiral building blocks to ordered helical superstructures remains a challenge. Here, we demonstrate that topological defects, such as screw dislocations, can drive the chirality transfer from particle to supramolecular structure level during the crystallization process. By using a model system of chiral particles, which enables direct imaging of single particle incorporation into growing crystals, we show that the crystallization kinetic pathway is the key parameter for monitoring, via the defects, the chirality amplification of the crystalline structures from racemic to predominantly homohelical. We provide an explanation based on the interplay between geometrical frustration, racemization induced by thermal fluctuations, and particle chirality. Our results demonstrate that screw dislocations not only promote the growth, but also control the chiral morphology and therefore the functionality of crystalline states.

The influence of reservoir heterogeneities on geothermal doublet performance

NARCIS (Netherlands)

Doddema, Leon

2012-01-01

SUMMARY The current main problem with deep geothermal energy in the Netherlands is the uncertainty in terms of attainable flow rate and life time. The goal of this research is therefore modeling a geothermal doublet in a heterogeneous reservoir, using a

Design study of a new vacuum vessel for Doublet III

International Nuclear Information System (INIS)

Rawls, J.M.; Davis, L.G.; Anderson, P.M.

1980-10-01

The principal thrust of the project was to examine a single design in enough depth to gain confidence in the feasibility and desirability of specific design features. However, a valuable spin-off of the project was to develop information of a more generic character to aid in future studies of possibilities for Doublet III. For example, we now feel that Doublet III can be reconfigured with any of a variety of new vacuum vessels, poloidal coil sets, and auxiliary heating systems within three years of project initiation, a period that is short compared to the time scale for developing a completely new facility. In addition, this can be accomplished at a fraction of the cost required to develop a comparable facility

Higgs bosons in the two-doublet model with CP violation

International Nuclear Information System (INIS)

Akhmetzyanova, E.; Dolgopolov, M.; Dubinin, M.

2005-01-01

We consider the effective two-Higgs-doublet potential with complex parameters, when the CP invariance is broken both explicitly and spontaneously. The diagonal mass term in the local minimum of the potential is constructed for the physical basis of Higgs fields, keeping explicitly the limiting case of CP conservation, if the parameters are taken real. For the special case of the two-doublet Higgs sector of the minimal supersymmetric model, when CP invariance is violated by the Higgs bosons interaction with scalar quarks of the third generation, we calculate by means of the effective potential method the Higgs boson masses and evaluate the two-fermion Higgs boson decay widths and the widths of rare one-loop-mediated decays H→γγ, H→gg

Vortex solutions in two-Higgs-doublet systems

International Nuclear Information System (INIS)

Bimonte, G.; Lozano, G.

1994-04-01

We analyze the existence of string-like defects in a two-Higgs-doublet system having SU(2) x U(1) y x U(1) y , as gauge group. We are able to show that, when certain relations among the parameters hold, these configurations satisfy a set of first order differential equations (Bogomol'nyi equations) and their energy is proportional to their topological charge. (author). 12 refs

Chirality dependence of dipole matrix element of carbon nanotubes in axial magnetic field: A third neighbor tight binding approach

Science.gov (United States)

Chegel, Raad; Behzad, Somayeh

2014-02-01

We have studied the electronic structure and dipole matrix element, D, of carbon nanotubes (CNTs) under magnetic field, using the third nearest neighbor tight binding model. It is shown that the 1NN and 3NN-TB band structures show differences such as the spacing and mixing of neighbor subbands. Applying the magnetic field leads to breaking the degeneracy behavior in the D transitions and creates new allowed transitions corresponding to the band modifications. It is found that |D| is proportional to the inverse tube radius and chiral angle. Our numerical results show that amount of filed induced splitting for the first optical peak is proportional to the magnetic field by the splitting rate ν11. It is shown that ν11 changes linearly and parabolicly with the chiral angle and radius, respectively.

Search for a lighter Higgs boson in Two Higgs Doublet Models

Energy Technology Data Exchange (ETDEWEB)

Cacciapaglia, Giacomo; Deandrea, Aldo; Gascon-Shotkin, Suzanne; Corre, Solène Le; Lethuillier, Morgan [University Lyon, Université Claude Bernard Lyon 1, CNRS/IN2P3, UMR5822 IPNL,4, rue E. Fermi, Villeurbanne, F-69622 (France); Tao, Junquan [Institute High Energy Physics, Chinese Academy of Sciences,P.O. Box 918, Beijing, 100049 (China)

2016-12-15

We consider present constraints on Two Higgs Doublet Models, both from the LHC at Run 1 and from other sources in order to explore the possibility of constraining a neutral scalar or pseudo-scalar particle lighter than the 125 GeV Higgs boson. Such a lighter particle is not yet completely excluded by present data. We show with a simplified analysis that some new constraints could be obtained at the LHC if such a search is performed by the experimental collaborations, which we therefore encourage to continue carrying out light diphoton resonance searches at √s=13 TeV in the context of Two Higgs Doublet Models.

Product fine-structure resolved photodissociation dynamics: The A band of H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Zhou, Linsen [Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Xie, Daiqian, E-mail: dqxie@nju.edu.cn, E-mail: hguo@unm.edu [Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Sun, Zhigang [State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Guo, Hua, E-mail: dqxie@nju.edu.cn, E-mail: hguo@unm.edu [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

2014-01-14

The photodissociation dynamics of H{sub 2}O in its first absorption band is investigated on an accurate potential energy surface based on a large number of high-level ab initio points. Several ro-vibrational states of the parent molecule are considered. Different from most previous theoretical studies, the spin-orbit and Λ-doublet populations of the open-shell OH fragment are reported from full-dimensional wave packet calculations. The populations of the two spin-orbit manifolds are in most cases close to the statistical limit, but the Λ-doublet is dominated by the A{sup ″} component, thanks largely to the fast in-plane dissociation of H{sub 2}O(A{sup ~1}A{sup ′′}). Comparisons with experimental data and a Franck-Condon model are generally very good, although some discrepancies exist.

Spin Chirality of Cu3 and V3 Nanomagnets. 1. Rotation Behavior of Vector Chirality, Scalar Chirality, and Magnetization in the Rotating Magnetic Field, Magnetochiral Correlations.

Science.gov (United States)

Belinsky, Moisey I

2016-05-02

The rotation behavior of the vector chirality κ, scalar chirality χ, and magnetization M in the rotating magnetic field H1 is considered for the V3 and Cu3 nanomagnets, in which the Dzialoshinsky-Moriya coupling is active. The polar rotation of the field H1 of the given strength H1 results in the energy spectrum characterized by different vector and scalar chiralities in the ground and excited states. The magnetochiral correlations between the vector and scalar chiralities, energy, and magnetization in the rotating field were considered. Under the uniform polar rotation of the field H1, the ground-state chirality vector κI performs sawtooth oscillations and the magnetization vector MI performs the sawtooth oscillating rotation that is accompanied by the correlated transformation of the scalar chirality χI. This demonstrates the magnetochiral effect of the joint rotation behavior and simultaneous frustrations of the spin chiralities and magnetization in the rotating field, which are governed by the correlation between the chiralities and magnetization.

Chiral forces and molecular dissymmetry

International Nuclear Information System (INIS)

Mohan, R.

1992-01-01

Chiral molecules leading to helical macromolecules seem to preserve information and extend it better. In the biological world RNA is the very paradigm for self-replication, elongation and autocatalytic editing. The nucleic acid itself is not chiral. It acquires its chirality by association with D-sugars. Although the chiral information or selectivity put in by the unit monomer is no longer of much interest to the biologists - they tend to leave it to the Darwinian selection principle to take care of it as illustrated by Frank's model - it is vital to understand the origin of chirality. There are three different approaches for the chiral origin of life: (1) Phenomenological, (2) Electromagnetic molecular and Coriolis forces and (3) Atomic or nuclear force, the neutral weak current. The phenomenological approach involves spontaneous symmetry breaking fluctuations in far for equilibrium systems or nucleation and crystallization. Chance plays a major role in the chiral molecule selected

Introduction to Chiral Symmetry

Energy Technology Data Exchange (ETDEWEB)

Koch, Volker [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-05-09

These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. We will also discuss some effective chiral models such as the linear and nonlinear sigma model as well as the essential ideas of chiral perturbation theory. We will present some applications to the physics of ultrarelativistic heavy ion collisionsd.

Introduction to chiral symmetry

International Nuclear Information System (INIS)

Koch, V.

1996-01-01

These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. Effective chiral models such as the linear and nonlinear sigma model will be discussed as well as the essential ideas of chiral perturbation theory. Some applications to the physics of ultrarelativistic heavy ion collisions will be presented

Chiral algebras for trinion theories

International Nuclear Information System (INIS)

Lemos, Madalena; Peelaers, Wolfger

2015-01-01

It was recently understood that one can identify a chiral algebra in any four-dimensional N=2 superconformal theory. In this note, we conjecture the full set of generators of the chiral algebras associated with the T n theories. The conjecture is motivated by making manifest the critical affine module structure in the graded partition function of the chiral algebras, which is computed by the Schur limit of the superconformal index for T n theories. We also explicitly construct the chiral algebra arising from the T 4 theory. Its null relations give rise to new T 4 Higgs branch chiral ring relations.

Simplified chiral superfield propagators for chiral constant mass superfields

International Nuclear Information System (INIS)

Srivastava, P.P.

1983-01-01

Unconstrained superfield potentials are introduced to derive Feynman rules for chiral superfields following conventional procedure which is easy and instructive. Propagators for the case when the mass parameters are constant chiral superfields are derived. The propagators reported here are very simple compared to those available in literature and allow a manageable calculation of higher loops. (Author) [pt

Role of Achiral Nucleobases in Multicomponent Chiral Self-Assembly: Purine-Triggered Helix and Chirality Transfer.

Science.gov (United States)

Deng, Ming; Zhang, Li; Jiang, Yuqian; Liu, Minghua

2016-11-21

Chiral self-assembly is a basic process in biological systems, where many chiral biomolecules such as amino acids and sugars play important roles. Achiral nucleobases usually covalently bond to saccharides and play a significant role in the formation of the double helix structure. However, it remains unclear how the achiral nucleobases can function in chiral self-assembly without the sugar modification. Herein, we have clarified that purine nucleobases could trigger N-(9-fluorenylmethox-ycarbonyl) (Fmoc)-protected glutamic acid to self-assemble into helical nanostructures. Moreover, the helical nanostructure could serve as a matrix and transfer the chirality to an achiral fluorescence probe, thioflavin T (ThT). Upon chirality transfer, the ThT showed not only supramolecular chirality but also circular polarized fluorescence (CPL). Without the nucleobase, the self-assembly processes cannot happen, thus providing an example where achiral molecules played an essential role in the expression and transfer of the chirality. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Trilinear Higgs couplings in the two Higgs doublet model with CP violation

International Nuclear Information System (INIS)

Osland, Per; Pandita, P. N.; Selbuz, Levent

2008-01-01

We carry out a detailed analysis of the general two Higgs doublet model with CP violation. We describe two different parametrizations of this model, and then study the Higgs boson masses and the trilinear Higgs couplings for these two parametrizations. Within a rather general model, we find that the trilinear Higgs couplings have a significant dependence on the details of the model, even when the lightest Higgs boson mass is taken to be a fixed parameter. We include radiative corrections in the one-loop effective potential approximation in our analysis of the Higgs boson masses and the Higgs trilinear couplings. The one-loop corrections to the trilinear couplings of the two Higgs doublet model also depend significantly on the details of the model, and can be rather large. We study quantitatively the trilinear Higgs couplings, and show that these couplings are typically several times larger than the corresponding standard model trilinear Higgs coupling in some regions of the parameter space. We also briefly discuss the decoupling limit of the two Higgs doublet model.

Timoshenko beam model for chiral materials

Science.gov (United States)

Ma, T. Y.; Wang, Y. N.; Yuan, L.; Wang, J. S.; Qin, Q. H.

2018-06-01

Natural and artificial chiral materials such as deoxyribonucleic acid (DNA), chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. In this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton's principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. It is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DNA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.

Electroweak phase transition in two Higgs doublet models

International Nuclear Information System (INIS)

Cline, J.M.; Lemieux, P.

1997-01-01

We reexamine the strength of the first-order phase transition in the electroweak theory supplemented by an extra Higgs doublet. The finite-temperature effective potential V eff is computed to one-loop order, including the summation of ring diagrams, to study the ratio φ c /T c of the Higgs field VEV to the critical temperature. We make a number of improvements over previous treatments, including a consistent treatment of Goldstone bosons in V eff , an accurate analytic approximation to V eff valid for any mass-to-temperature ratios, and use of the experimentally measured top quark mass. For two-Higgs-doublet models, we identify a significant region of parameter space where φ c /T c is large enough for electroweak baryogenesis, and we argue that this identification should persist even at higher orders in perturbation theory. In the case of the minimal supersymmetric standard model, our results indicate that the extra Higgs bosons have little effect on the strength of the phase transition. copyright 1997 The American Physical Society

Collisional broadening of alkali doublets by helium perturbers

Energy Technology Data Exchange (ETDEWEB)

Mullamphy, D F T [School of Mathematics, Physics and Information Technology, James Cook University, Townsville 4811 (Australia); Peach, G [Department of Physics and Astronomy, University College London WC1E 6BT (United Kingdom); Venturi, V [School of Mathematics, Physics and Information Technology, James Cook University, Townsville 4811 (Australia); Whittingham, I B [School of Mathematics, Physics and Information Technology, James Cook University, Townsville 4811 (Australia); Gibson, S J [School of Mathematics, Physics and Information Technology, James Cook University, Townsville 4811 (Australia)

2007-03-28

We report results for the Lorentzian profiles of the Li I, Na I and K I doublets and the Na I subordinate doublet broadened by helium perturbers for temperatures up to 3000 K. They have been obtained from a fully quantum-mechanical close-coupling description of the colliding atoms, the Baranger theory of line shapes and new ab initio potentials for the alkali-helium interaction. For all lines except the 769.9 nm K I line, the temperature dependence of the widths over the range 70 {<=} T {<=} 3000 K is accurately represented by the power law form w = aT{sup bb} with 0.38 < b < 0.43. The 769.9 nm K I line has this form for 500 {<=} T {<=} 3000 K with b having the higher value of 0.49. Although the shifts have a more complex temperature dependence, they all have the general feature of increasing with temperature above T {approx} 500 K apart from the 769.9 K I line whose shift decreases with temperature.

The flavor-locked flavorful two Higgs doublet model

Science.gov (United States)

Altmannshofer, Wolfgang; Gori, Stefania; Robinson, Dean J.; Tuckler, Douglas

2018-03-01

We propose a new framework to generate the Standard Model (SM) quark flavor hierarchies in the context of two Higgs doublet models (2HDM). The `flavorful' 2HDM couples the SM-like Higgs doublet exclusively to the third quark generation, while the first two generations couple exclusively to an additional source of electroweak symmetry breaking, potentially generating striking collider signatures. We synthesize the flavorful 2HDM with the `flavor-locking' mechanism, that dynamically generates large quark mass hierarchies through a flavor-blind portal to distinct flavon and hierarchon sectors: dynamical alignment of the flavons allows a unique hierarchon to control the respective quark masses. We further develop the theoretical construction of this mechanism, and show that in the context of a flavorful 2HDM-type setup, it can automatically achieve realistic flavor structures: the CKM matrix is automatically hierarchical with | V cb | and | V ub | generically of the observed size. Exotic contributions to meson oscillation observables may also be generated, that may accommodate current data mildly better than the SM itself.

Material failures observed in Doublet III neutral beamlines

International Nuclear Information System (INIS)

Bailey, E.W.; Colleraine, A.; Doll, D.; Grunloh, H.; Kim, J.; Langhorn, A.; Thurgood, B.

1983-12-01

The Doublet III neutral beam injectors consist of three separable spools two meters in diameter by four meters long overall when assembled. Contained within these spools are the neutralizers, ion dumps, deflecting magnet, calorimeter dumps, cryogenic panels and beam scraping collimators 3,7. To date three beamlines are in operation on Doublet III, and the beams have accumulated operating time of approximately 32 months, with the oldest having been in operation for 18 months. During this time operation of DIII with the neutral beam sources has demonstrated the following: 7.8 MW injected neutrals from three beamlines (6 sources), high β (4.5%), and non-circular plasma shape. The sources have also exhibited a very reliable injected shot history 4, 5, 6, 8. Material failures encountered during the operation of DIII N.B. injectors and the solutions to these failures are described. Failures include cracking of the neutralizer exit collimator due to heating cycles, failure of cyropanel support rods due to cooling cycles, failure of the sliding drive of the moveable calorimeter due to friction

Enantiopure Ferrocene-Based Planar-Chiral Iridacycles: Stereospecific Control of Iridium-Centred Chirality.

Science.gov (United States)

Arthurs, Ross A; Ismail, Muhammad; Prior, Christopher C; Oganesyan, Vasily S; Horton, Peter N; Coles, Simon J; Richards, Christopher J

2016-02-24

Reaction of [IrCp*Cl2 ]2 with ferrocenylimines (Fc=NAr, Ar=Ph, p-MeOC6 H4 ) results in ferrocene C-H activation and the diastereoselective synthesis of half-sandwich iridacycles of relative configuration Sp *,RIr *. Extension to (S)-2-ferrocenyl-4-(1-methylethyl)oxazoline gave highly diastereoselective control over the new elements of planar chirality and metal-based pseudo-tetrahedral chirality, to give both neutral and cationic half-sandwich iridacycles of absolute configuration Sc ,Sp ,RIr . Substitution reactions proceed with retention of configuration, with the planar chirality controlling the metal-centred chirality through an iron-iridium interaction in the coordinatively unsaturated cationic intermediate. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Conceptual design summary for modifying Doublet III to a large dee-shaped configuration

International Nuclear Information System (INIS)

Davis, L.G.; Gallix, R.; Luxon, J.L.; Mahdavi, M.A.; Puhn, F.A.; Rock, P.J.; Wesley, J.C.

1983-05-01

The Doublet III tokamak is to be reconfigured by replacing its indented (doublet) vacuum vessel with a larger one of a dee-shaped cross section. This change will permit significantly larger elongated plasmas than is presently possible and will allow higher plasma current (up to 5 MA) and anticipated longer confinement time. Reactor relevant values of stable beta and plasma pressure are predicted. This modification, while resulting in a significant change in capability, utilizes most of the existing coils, structure, systems and facility

Two Higgs doublets in SO(10) model

International Nuclear Information System (INIS)

Asatryan, G.M.

1989-01-01

An SO(10) grand unification model is suggested with two light Higgs doublets, whose vacuum expectation values are connected with the SU(2) L xU(1) Y electroweak group breaking. Taking into account the naturality condition associated with absence of flavor changing neutral currents, a certain form of the quark mass matrices. As a result, the proton lifetime in the SO(10) model turns to be strongly restrained

On the connectivity anisotropy in fluvial Hot Sedimentary Aquifers and its influence on geothermal doublet performance

DEFF Research Database (Denmark)

Willems, Cees J.L.; Nick, Hamid; Donselaar, Marinus E.

2017-01-01

This study finds that the geothermal doublet layout with respect to the paleo flow direction in fluvial sedimentary reservoirs could significantly affect pump energy losses. These losses can be reduced by up to 10% if a doublet well pair is oriented parallel to the paleo flow trend compared...

Chiral Responsive Liquid Quantum Dots.

Science.gov (United States)

Zhang, Jin; Ma, Junkai; Shi, Fangdan; Tian, Demei; Li, Haibing

2017-08-01

How to convert the weak chiral-interaction into the macroscopic properties of materials remains a huge challenge. Here, this study develops highly fluorescent, selectively chiral-responsive liquid quantum dots (liquid QDs) based on the hydrophobic interaction between the chiral chains and the oleic acid-stabilized QDs, which have been designated as (S)-1810-QDs. The fluorescence spectrum and liquidity of thermal control demonstrate the fluorescence properties and the fluidic behavior of (S)-1810-QDs in the solvent-free state. Especially, (S)-1810-QDs exhibit a highly chiral-selective response toward (1R, 2S)-2-amino-1,2-diphenyl ethanol. It is anticipated that this study will facilitate the construction of smart chiral fluidic sensors. More importantly, (S)-1810-QDs can become an attractive material for chiral separation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Topological Magnon Bands in a Kagome Lattice Ferromagnet.

Science.gov (United States)

Chisnell, R; Helton, J S; Freedman, D E; Singh, D K; Bewley, R I; Nocera, D G; Lee, Y S

2015-10-02

There is great interest in finding materials possessing quasiparticles with topological properties. Such materials may have novel excitations that exist on their boundaries which are protected against disorder. We report experimental evidence that magnons in an insulating kagome ferromagnet can have a topological band structure. Our neutron scattering measurements further reveal that one of the bands is flat due to the unique geometry of the kagome lattice. Spin wave calculations show that the measured band structure follows from a simple Heisenberg Hamiltonian with a Dzyaloshinkii-Moriya interaction. This serves as the first realization of an effectively two-dimensional topological magnon insulator--a new class of magnetic material that should display both a magnon Hall effect and protected chiral edge modes.

Autler-Townes doublet and electromagnetically induced transparency resonance probed by an ultrashort pulse train

International Nuclear Information System (INIS)

Soares, A A; De Araujo, Luis E E

2010-01-01

We study theoretically the interaction between an ultrashort pulse train and a three-level atom driven by a cw laser. We show that the pulse train can be employed to observe spectra of Autler-Townes doublet and electromagnetically induced transparency resonance that are time and frequency resolved. The observation of subnatural linewidth features associated with the electromagnetically induced transparency resonance is described. The temporal evolution of electromagnetically induced transparency of the pulse train is shown to exhibit new and different features compared to that of the related phenomenon of coherent population trapping. By matching the tooth separation of the frequency comb associated with the pulse train to that of the Autler-Townes doublet, quantum beats between the doublet components can be induced. We show that coherent accumulation of excitation plays a major role in the two studied phenomena.

Generation of deviation parameters for amino acid singlets, doublets ...

Indian Academy of Sciences (India)

We present a new method, secondary structure prediction by deviation parameter (SSPDP) for predicting the secondary structure of proteins from amino acid sequence. Deviation parameters (DP) for amino acid singlets, doublets and triplets were computed with respect to secondary structural elements of proteins based on ...

Applications of chiral symmetry

International Nuclear Information System (INIS)

Pisarski, R.D.

1995-03-01

The author discusses several topics in the applications of chiral symmetry at nonzero temperature. First, where does the rho go? The answer: up. The restoration of chiral symmetry at a temperature T χ implies that the ρ and a 1 vector mesons are degenerate in mass. In a gauged linear sigma model the ρ mass increases with temperature, m ρ (T χ ) > m ρ (0). The author conjectures that at T χ the thermal ρ - a 1 , peak is relatively high, at about ∼1 GeV, with a width approximately that at zero temperature (up to standard kinematic factors). The ω meson also increases in mass, nearly degenerate with the ρ, but its width grows dramatically with temperature, increasing to at least ∼100 MeV by T χ . The author also stresses how utterly remarkable the principle of vector meson dominance is, when viewed from the modern perspective of the renormalization group. Secondly, he discusses the possible appearance of disoriented chiral condensates from open-quotes quenchedclose quotes heavy ion collisions. It appears difficult to obtain large domains of disoriented chiral condensates in the standard two flavor model. This leads to the last topic, which is the phase diagram for QCD with three flavors, and its proximity to the chiral critical point. QCD may be very near this chiral critical point, and one might thereby generated large domains of disoriented chiral condensates

Penguin effects induced by the two-Higgs-doublet model and charmless B-meson decays

International Nuclear Information System (INIS)

Davies, A.J.; Joshi, G.C.; Matsuda, M.

1991-03-01

Nonstandard physical effects through the penguin diagram induced by the charged Higgs scalar contribution in the two-Higgs-doublet model are analysed. The non-leptonic β-decay processes including the non-standard two-Higgs-doublet contribution are compared with the standard model results, which arise from the magnetic gluon transition term. The charged Higgs contribution gives a sizable enhancement to the branching fractions of β-meson charmless decay. 13 refs., 4 figs

Helical Polyacetylenes Induced via Noncovalent Chiral Interactions and Their Applications as Chiral Materials.

Science.gov (United States)

Maeda, Katsuhiro; Yashima, Eiji

2017-08-01

Construction of predominantly one-handed helical polyacetylenes with a desired helix sense utilizing noncovalent chiral interactions with nonracemic chiral guest compounds based on a supramolecular approach is described. As with the conventional dynamic helical polymers possessing optically active pendant groups covalently bonded to the polymer chains, this noncovalent helicity induction system can show significant chiral amplification phenomena, in which the chiral information of the nonracemic guests can transfer with high cooperativity through noncovalent bonding interactions to induce an almost single-handed helical conformation in the polymer backbone. An intriguing "memory effect" of the induced macromolecular helicity is observed for some polyacetylenes, which means that the helical conformations induced in dynamic helical polyacetylene can be transformed into metastable static ones by tuning their helix-inversion barriers. Potential applications of helical polyacetylenes with controlled helix sense constructed by the "noncovalent helicity induction and/or memory effect" as chiral materials are also described.

Increments to chiral recognition facilitating enantiomer separations of chiral acids, bases, and ampholytes using Cinchona-based zwitterion exchanger chiral stationary phases.

Science.gov (United States)

Wernisch, Stefanie; Pell, Reinhard; Lindner, Wolfgang

2012-07-01

The intramolecular distances of anion and cation exchanger sites of zwitterionic chiral stationary phases represent potential tuning sites for enantiomer selectivity. In this contribution, we investigate the influence of alkanesulfonic acid chain length and flexibility on enantiomer separations of chiral acids, bases, and amphoteric molecules for six Cinchona alkaloid-based chiral stationary phases in comparison with structurally related anion and cation exchangers. Employing polar-organic elution conditions, we observed an intramolecular counterion effect for acidic analytes which led to reduced retention times but did not impair enantiomer selectivities. Retention of amphoteric analytes is based on simultaneous double ion pairing of their charged functional groups with the acidic and basic sites of the zwitterionic selectors. A chiral center in the vicinity of the strong cation exchanger site is vital for chiral separations of bases. Sterically demanding side chains are beneficial for separations of free amino acids. Enantioseparations of free (un-derivatized) peptides were particularly successful in stationary phases with straight-chain alkanesulfonic acid sites, pointing to a beneficial influence of more flexible moieties. In addition, we observed pseudo-enantiomeric behavior of quinine and quinidine-derived chiral stationary phases facilitating reversal of elution orders for all analytes. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chiral Synthons in Pesticide Syntheses

NARCIS (Netherlands)

Feringa, Bernard

1988-01-01

The use of chiral synthons in the preparation of enantiomerically pure pesticides is described in this chapter. Several routes to chiral synthons based on asymmetric synthesis or on natural products are illustrated. Important sources of chiral building blocks are reviewed. Furthermore the

Chiral bag model

International Nuclear Information System (INIS)

Musakhanov, M.M.

1980-01-01

The chiral bag model is considered. It is suggested that pions interact only with the surface of a quark ''bag'' and do not penetrate inside. In the case of a large bag the pion field is rather weak and goes to the linearized chiral bag model. Within that model the baryon mass spectrum, β decay axial constant, magnetic moments of baryons, pion-baryon coupling constants and their form factors are calculated. It is shown that pion corrections to the calculations according to the chiral bag model is essential. The obtained results are found to be in a reasonable agreement with the experimental data

Cell Chirality Drives Left-Right Asymmetric Morphogenesis.

Science.gov (United States)

Inaki, Mikiko; Sasamura, Takeshi; Matsuno, Kenji

2018-01-01

Most macromolecules found in cells are chiral, meaning that they cannot be superimposed onto their mirror image. However, cells themselves can also be chiral, a subject that has received little attention until very recently. In our studies on the mechanisms of left-right (LR) asymmetric development in Drosophila , we discovered that cells can have an intrinsic chirality to their structure, and that this "cell chirality" is generally responsible for the LR asymmetric development of certain organs in this species. The actin cytoskeleton plays important roles in the formation of cell chirality. In addition, Myosin31DF ( Myo31DF ), which encodes Drosophila Myosin ID, was identified as a molecular switch for cell chirality. In other invertebrate species, including snails and Caenorhabditis elegans , chirality of the blastomeres, another type of cell chirality, determines the LR asymmetry of structures in the body. Thus, chirality at the cellular level may broadly contribute to LR asymmetric development in various invertebrate species. Recently, cell chirality was also reported for various vertebrate cultured cells, and studies suggested that cell chirality is evolutionarily conserved, including the essential role of the actin cytoskeleton. Although the biological roles of cell chirality in vertebrates remain unknown, it may control LR asymmetric development or other morphogenetic events. The investigation of cell chirality has just begun, and this new field should provide valuable new insights in biology and medicine.

Isotopic chirality

Energy Technology Data Exchange (ETDEWEB)

Floss, H.G. [Univ. of Washington, Seattle, WA (United States)

1994-12-01

This paper deals with compounds that are chiral-at least in part, due to isotope substitution-and their use in tracing the steric course of enzyme reaction in vitro and in vivo. There are other applications of isotopically chiral compounds (for example, in analyzing the steric course of nonenzymatic reactions and in probing the conformation of biomolecules) that are important but they will not be discussed in this context.

Relativistic Chiral Kinetic Theory

International Nuclear Information System (INIS)

Stephanov, Mikhail

2016-01-01

This very brief review of the recent progress in chiral kinetic theory is based on the results of Refs. [J.-Y. Chen, D. T. Son, M. A. Stephanov, H.-U. Yee, Y. Yin, Lorentz Invariance in Chiral Kinetic Theory, Phys. Rev. Lett. 113 (18) (2014) 182302. doi: (10.1103/PhysRevLett.113.182302); J.-Y. Chen, D. T. Son, M. A. Stephanov, Collisions in Chiral Kinetic Theory, Phys. Rev. Lett. 115 (2) (2015) 021601. doi: (10.1103/PhysRevLett.115.021601); M. A. Stephanov, H.-U. Yee, The no-drag frame for anomalous chiral fluid, Phys. Rev. Lett. 116 (12) (2016) 122302. doi: (10.1103/PhysRevLett.116.122302)].

Relativistic Chiral Kinetic Theory

Energy Technology Data Exchange (ETDEWEB)

Stephanov, Mikhail

2016-12-15

This very brief review of the recent progress in chiral kinetic theory is based on the results of Refs. [J.-Y. Chen, D. T. Son, M. A. Stephanov, H.-U. Yee, Y. Yin, Lorentz Invariance in Chiral Kinetic Theory, Phys. Rev. Lett. 113 (18) (2014) 182302. doi: (10.1103/PhysRevLett.113.182302); J.-Y. Chen, D. T. Son, M. A. Stephanov, Collisions in Chiral Kinetic Theory, Phys. Rev. Lett. 115 (2) (2015) 021601. doi: (10.1103/PhysRevLett.115.021601); M. A. Stephanov, H.-U. Yee, The no-drag frame for anomalous chiral fluid, Phys. Rev. Lett. 116 (12) (2016) 122302. doi: (10.1103/PhysRevLett.116.122302)].

Pure chiral optical fibres.

Science.gov (United States)

Poladian, L; Straton, M; Docherty, A; Argyros, A

2011-01-17

We investigate the properties of optical fibres made from chiral materials, in which a contrast in optical activity forms the waveguide, rather than a contrast in the refractive index; we refer to such structures as pure chiral fibres. We present a mathematical formulation for solving the modes of circularly symmetric examples of such fibres and examine the guidance and polarisation properties of pure chiral step-index, Bragg and photonic crystal fibre designs. Their behaviour is shown to differ for left- and right-hand circular polarisation, allowing circular polarisations to be isolated and/or guided by different mechanisms, as well as differing from equivalent non-chiral fibres. The strength of optical activity required in each case is quantified.

Probing the Chiral Anomaly via Nonlocal Transport in Weyl Semimetals

Science.gov (United States)

Parameswaran, Siddharth; Grover, Tarun; Vishwanath, Ashvin

2013-03-01

Weyl semimetals are three-dimensional analogs of graphene in which a pair of bands touch at points in momentum space, known as Weyl nodes. Electrons originating from a single Weyl node possess a definite topological charge, the chirality. Consequently, they exhibit the Adler-Jackiw-Bell anomaly, which in this condensed matter realization implies that application of parallel electric (E) and magnetic fields (B) pumps electrons between nodes of opposite chirality at a rate proportional to E . B . We argue that this pumping is measurable via transport experiments, in the limit of weak internode scattering. Specifically, we show that injecting a current in a Weyl semimetal subject to an E . B term leads to nonlocal features in transport. We acknowledge support of the Simons Foundation, NSF Grant PHY-1066293 and the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231

Chiral perturbation theory with nucleons

International Nuclear Information System (INIS)

Meissner, U.G.

1991-09-01

I review the constraints posed on the interactions of pions, nucleons and photons by the spontaneously broken chiral symmetry of QCD. The framework to perform these calculations, chiral perturbation theory, is briefly discussed in the meson sector. The method is a simultaneous expansion of the Greens functions in powers of external moments and quark masses around the massless case, the chiral limit. To perform this expansion, use is made of a phenomenological Lagrangian which encodes the Ward-identities and pertinent symmetries of QCD. The concept of chiral power counting is introduced. The main part of the lectures of consists in describing how to include baryons (nucleons) and how the chiral structure is modified by the fact that the nucleon mass in the chiral limit does not vanish. Particular emphasis is put on working out applications to show the strengths and limitations of the methods. Some processes which are discussed are threshold photopion production, low-energy compton scattering off nucleons, πN scattering and the σ-term. The implications of the broken chiral symmetry on the nuclear forces are briefly described. An alternative approach, in which the baryons are treated as very heavy fields, is touched upon

Two-Higgs-doublet-portal dark-matter models in light of direct search and LHC data

Energy Technology Data Exchange (ETDEWEB)

Chang, Chia-Feng [Department of Physics and Center for Theoretical Sciences, National Taiwan University,No. 1, Sec. 4, Roosevelt Rd., Taipei 106, Taiwan (China); He, Xiao-Gang [Department of Physics and Center for Theoretical Sciences, National Taiwan University,No. 1, Sec. 4, Roosevelt Rd., Taipei 106, Taiwan (China); INPAC, Department of Physics and Astronomy, Shanghai Jiao Tong University,800 Dongchuan Rd., Minhang, Shanghai 200240 (China); Physics Division, National Center for Theoretical Sciences,No. 101, Sec. 2, Kuang Fu Rd., Hsinchu 300, Taiwan (China); Tandean, Jusak [Department of Physics and Center for Theoretical Sciences, National Taiwan University,No. 1, Sec. 4, Roosevelt Rd., Taipei 106, Taiwan (China); Physics Division, National Center for Theoretical Sciences,No. 101, Sec. 2, Kuang Fu Rd., Hsinchu 300, Taiwan (China)

2017-04-19

We explore simple Higgs-portal models of dark matter (DM) with spin 1/2, 3/2, and 1, respectively, applying to them constraints from the LUX and PandaX-II direct detection experiments and from LHC measurements on the 125-GeV Higgs boson. With only one Higgs doublet, we find that the spin-1/2 DM having a purely scalar effective coupling to the doublet is viable only in a narrow range of mass near the Higgs pole, whereas the vector DM is still allowed if its mass is also close to the Higgs pole or exceeds 1.4 TeV, both in line with earlier analyses. Moreover, the spin-3/2 DM is in a roughly similar situation to the spin-1/2 DM, but has surviving parameter space which is even more restricted. We also consider the two-Higgs-doublet extension of each of the preceding models, assuming that the expanded Yukawa sector is that of the two-Higgs-doublet model of type II. We show that in these two-Higgs-doublet-portal models significant portions of the DM mass regions excluded in the simplest scenarios by direct search bounds can be reclaimed due to suppression of the effective DM interactions with nucleons at some ratios of the CP-even Higgs bosons’ couplings to the up and down quarks. The regained parameter space contains areas which can yield a DM-nucleon scattering cross-section that is far less than its current experimental limit or even goes below the neutrino-background floor.

Chiral magnetic effect of light

Science.gov (United States)

Hayata, Tomoya

2018-05-01

We study a photonic analog of the chiral magnetic (vortical) effect. We discuss that the vector component of magnetoelectric tensors plays a role of "vector potential," and its rotation is understood as "magnetic field" of a light. Using the geometrical optics approximation, we show that "magnetic fields" cause an anomalous shift of a wave packet of a light through an interplay with the Berry curvature of photons. The mechanism is the same as that of the chiral magnetic (vortical) effect of a chiral fermion, so that we term the anomalous shift "chiral magnetic effect of a light." We further study the chiral magnetic effect of a light beyond geometric optics by directly solving the transmission problem of a wave packet at a surface of a magnetoelectric material. We show that the experimental signal of the chiral magnetic effect of a light is the nonvanishing of transverse displacements for the beam normally incident to a magnetoelectric material.

Vapor deposition on doublet airfoil substrates: Control of coating thickness and microstructure

Energy Technology Data Exchange (ETDEWEB)

Rodgers, Theron M.; Zhao, Hengbei; Wadley, Haydn N. G., E-mail: haydn@virginia.edu [Department of Materials Science and Engineering, University of Virginia, 395 McCormick Rd., P.O. Box 400745, Charlottesville, Virginia 22904 (United States)

2015-11-15

Gas jet assisted vapor deposition processes for depositing coatings are conducted at higher pressures than conventional physical vapor deposition methods, and have shown promise for coating complex shaped substrates including those with non-line-of-sight (NLS) regions on their surface. These regions typically receive vapor atoms at a lower rate and with a wider incident angular distribution than substrate regions in line-of-sight (LS) of the vapor source. To investigate the coating of such substrates, the thickness and microstructure variation along the inner (curved) surfaces of a model doublet airfoil containing both LS and NLS regions has been investigated. Results from atomistic simulations and experiments confirm that the coating's thickness is thinner in flux-shadowed regions than in other regions for all the coating processes investigated. They also indicated that the coatings columnar microstructure and pore volume fraction vary with surface location through the LS to NLS transition zone. A substrate rotation strategy for optimizing the thickness over the entire doublet airfoil surface was investigated, and led to the identification of a process that resulted in only small variation of coating thickness, columnar growth angle, and pore volume fraction on all doublet airfoil surfaces.

QCD and the chiral critical point

International Nuclear Information System (INIS)

Gavin, S.; Gocksch, A.; Pisarski, R.D.

1994-01-01

As an extension of QCD, consider a theory with ''2+1'' flavors, where the current quark masses are held in a fixed ratio as the overall scale of the quark masses is varied. At nonzero temperature and baryon density it is expected that in the chiral limit the chiral phase transition is of first order. Increasing the quark mass from zero, the chiral transition becomes more weakly first order, and can end in a chiral critical point. We show that the only massless field at the chiral critical point is a σ meson, with the universality class that of the Ising model. Present day lattice simulations indicate that QCD is (relatively) near to the chiral critical point

Chirality-dependent cellular uptake of chiral nanocarriers and intracellular delivery of different amounts of guest molecules

Science.gov (United States)

Kehr, Nermin Seda; Jose, Joachim

2017-12-01

We demonstrate the organic molecules loaded and chiral polymers coated periodic mesoporous organosilica (PMO) to generate chiral nanocarriers that we used to study chirality-dependent cellular uptake in serum and serum-free media and the subsequent delivery of different amounts of organic molecules into cells. Our results show that the amount of internalized PMO and thus the transported amount of organic molecules by nanocarrier PMO into cells was chirality dependent and controlled by hard/soft protein corona formation on the PMO surfaces. Therefore, this study demonstrate that chiral porous nanocarriers could potentially be used as advanced drug delivery systems which are able to use the specific chiral surface-protein interactions to influence/control the amount of (bio)active molecules delivered to cells in drug delivery and/or imaging applications.

Chiral dynamics of baryons in the perturbative chiral quark model

Energy Technology Data Exchange (ETDEWEB)

Pumsa-ard, K.

2006-07-01

In this work we develop and apply variants of a perturbative chiral quark model (PCQM) to the study of baryonic properties dominantly in the low-energy region. In a first step we consider a noncovariant form of the PCQM, where confinement is modelled by a static, effective potential and chiral corrections are treated to second order, in line with similar chiral quark models. We apply the PCQM to the study of the electromagnetic form factors of the baryon octet. We focus in particular on the low-energy observables such as the magnetic moments, the charge and magnetic radii. In addition, the electromagnetic N-delta transition is also studied in the framework of the PCQM. In the chiral loop calculations we consider a quark propagator, which is restricted to the quark ground state, or in hadronic language to nucleon and delta intermediate states, for simplicity. We furthermore include the low-lying excited states to the quark propagator. In particular, the charge radius of the neutron and the transverse helicity amplitudes of the N-delta transition are considerably improved by this additional effect. In a next step we develop a manifestly Lorentz covariant version of the PCQM, where in addition higher order chiral corrections are included. The full chiral quark Lagrangian is motivated by and in analogy to the one of Chiral Perturbation Theory (ChPT). This Lagrangian contains a set of low energy constants (LECs), which are parameters encoding short distance effects and heavy degrees of freedom. We evaluate the chiral Lagrangian to order O(p{sup 4}) and to one loop to generate the dressing of the bare quark operators by pseudoscalar mesons. In addition we include the vector meson degrees of freedom in our study. Projection of the dressed quark operators on the baryonic level serves to calculate the relevant matrix elements. In a first application of this scheme, we resort to a parameterization of the valence quark form factors in the electromagnetic sector. Constraints

Detecting the chirality for coupled quantum dots

International Nuclear Information System (INIS)

Cao Huijuan; Hu Lian

2008-01-01

We propose a scheme to detect the chirality for a system consisting of three coupled quantum dots. The chirality is found to be determined by the frequency of the transition between chiral states under the chiral symmetry broken perturbation. The results are important to construct quantum gates and to demonstrate chiral entangle states in the triangle spin dots

Oscillation damping of chiral string loops

International Nuclear Information System (INIS)

Babichev, Eugeny; Dokuchaev, Vyacheslav

2002-01-01

Chiral cosmic string loops tend to the stationary (vorton) configuration due to energy loss into gravitational and electromagnetic radiation. We describe the asymptotic behavior of near stationary chiral loops and their fading to vortons. General limits on the gravitational and electromagnetic energy losses by near stationary chiral loops are found. For these loops we estimate the oscillation damping time. We present solvable examples of gravitational radiation energy loss by some chiral loop configurations. The analytical dependence of string energy with time is found in the case of the chiral ring with small amplitude radial oscillations

Chiral algebras of class S

CERN Document Server

Beem, Christopher; Rastelli, Leonardo; van Rees, Balt C.

2015-01-01

Four-dimensional N=2 superconformal field theories have families of protected correlation functions that possess the structure of two-dimensional chiral algebras. In this paper, we explore the chiral algebras that arise in this manner in the context of theories of class S. The class S duality web implies nontrivial associativity properties for the corresponding chiral algebras, the structure of which is best summarized in the language of generalized topological quantum field theory. We make a number of conjectures regarding the chiral algebras associated to various strongly coupled fixed points.

Nanoscale chirality in metal and semiconductor nanoparticles.

Science.gov (United States)

Kumar, Jatish; Thomas, K George; Liz-Marzán, Luis M

2016-10-18

The field of chirality has recently seen a rejuvenation due to the observation of chirality in inorganic nanomaterials. The advancements in understanding the origin of nanoscale chirality and the potential applications of chiroptical nanomaterials in the areas of optics, catalysis and biosensing, among others, have opened up new avenues toward new concepts and design of novel materials. In this article, we review the concept of nanoscale chirality in metal nanoclusters and semiconductor quantum dots, then focus on recent experimental and theoretical advances in chiral metal nanoparticles and plasmonic chirality. Selected examples of potential applications and an outlook on the research on chiral nanomaterials are additionally provided.

Absence of paired crossing in the positive parity bands of 124Cs

Science.gov (United States)

Singh, A. K.; Basu, A.; Nag, Somnath; Hübel, H.; Domscheit, J.; Ragnarsson, I.; Al-Khatib, A.; Hagemann, G. B.; Herskind, B.; Elema, D. R.; Wilson, J. N.; Clark, R. M.; Cromaz, M.; Fallon, P.; Görgen, A.; Lee, I.-Y.; Ward, D.; Ma, W. C.

2018-02-01

High-spin states in 124Cs were populated in the 64Ni(64Ni,p 3 n ) reaction and the Gammasphere detector array was used to measure γ -ray coincidences. Both positive- and negative-parity bands, including bands with chiral configurations, have been extended to higher spin, where a shape change has been observed. The configurations of the bands before and after the alignment are discussed within the framework of the cranked Nilsson-Strutinsky model. The calculations suggest that the nucleus undergoes a shape transition from triaxial to prolate around spin I ≃22 of the positive-parity states. The alignment gain of 8 ℏ , observed in the positive-parity bands, is due to partial alignment of several valence nucleons. This indicates the absence of band crossing due to paired nucleons in the bands.

Chiral Thirring–Wess model

Energy Technology Data Exchange (ETDEWEB)

Rahaman, Anisur, E-mail: anisur.rahman@saha.ac.in

2015-10-15

The vector type of interaction of the Thirring–Wess model was replaced by the chiral type and a new model was presented which was termed as chiral Thirring–Wess model in Rahaman (2015). The model was studied there with a Faddeevian class of regularization. Few ambiguity parameters were allowed there with the apprehension that unitarity might be threatened like the chiral generation of the Schwinger model. In the present work it has been shown that no counter term containing the regularization ambiguity is needed for this model to be physically sensible. So the chiral Thirring–Wess model is studied here without the presence of any ambiguity parameter and it has been found that the model not only remains exactly solvable but also does not lose the unitarity like the chiral generation of the Schwinger model. The phase space structure and the theoretical spectrum of this new model have been determined in the present scenario. The theoretical spectrum is found to contain a massive boson with ambiguity free mass and a massless boson.

Chiral Thirring–Wess model

International Nuclear Information System (INIS)

Rahaman, Anisur

2015-01-01

The vector type of interaction of the Thirring–Wess model was replaced by the chiral type and a new model was presented which was termed as chiral Thirring–Wess model in Rahaman (2015). The model was studied there with a Faddeevian class of regularization. Few ambiguity parameters were allowed there with the apprehension that unitarity might be threatened like the chiral generation of the Schwinger model. In the present work it has been shown that no counter term containing the regularization ambiguity is needed for this model to be physically sensible. So the chiral Thirring–Wess model is studied here without the presence of any ambiguity parameter and it has been found that the model not only remains exactly solvable but also does not lose the unitarity like the chiral generation of the Schwinger model. The phase space structure and the theoretical spectrum of this new model have been determined in the present scenario. The theoretical spectrum is found to contain a massive boson with ambiguity free mass and a massless boson

Band structure of hydrogenated Si nanosheets and nanotubes

International Nuclear Information System (INIS)

Guzman-Verri, G G; Lew Yan Voon, L C

2011-01-01

The band structures of fully hydrogenated Si nanosheets and nanotubes are elucidated by the use of an empirical tight-binding model. The hydrogenated Si sheet is a semiconductor with an indirect band gap of about 2.2 eV. The symmetries of the wavefunctions allow us to explain the origin of the gap. We predict that, for certain chiralities, hydrogenated Si nanotubes represent a new type of semiconductor, one with coexisting direct and indirect gaps of exactly the same magnitude. This behavior is different from that governed by the Hamada rule established for non-hydrogenated carbon and silicon nanotubes. A comparison to the results of an ab initio calculation is made.

Broadband reflection of polymer-stabilized chiral nematic liquid crystals induced by a chiral azobenzene compound.

Science.gov (United States)

Chen, Xingwu; Wang, Ling; Chen, Yinjie; Li, Chenyue; Hou, Guoyan; Liu, Xin; Zhang, Xiaoguang; He, Wanli; Yang, Huai

2014-01-21

A chiral nematic liquid crystal-photopolymerizable monomer-chiral azobenzene compound composite was prepared and then polymerized under UV irradiation. The reflection wavelength of the composite can be extended to cover the 1000-2400 nm range and also be adjusted to the visible light region by controlling the concentration of chiral compounds.

Standard model fermion hierarchies with multiple Higgs doublets

International Nuclear Information System (INIS)

Solaguren-Beascoa Negre, Ana

2016-01-01

The hierarchies between the Standard Model (SM) fermion masses and mixing angles and the origin of neutrino masses are two of the biggest mysteries in particle physics. We extend the SM with new Higgs doublets to solve these issues. The lightest fermion masses and the mixing angles are generated through radiative effects, correctly reproducing the hierarchy pattern. Neutrino masses are generated in the see-saw mechanism.

Orientation-Dependent Handedness and Chiral Design

Directory of Open Access Journals (Sweden)

Efi Efrati

2014-01-01

Full Text Available Chirality occupies a central role in fields ranging from biological self-assembly to the design of optical metamaterials. The definition of chirality, as given by Lord Kelvin, associates chirality with the lack of mirror symmetry: the inability to superpose an object on its mirror image. While this definition has guided the classification of chiral objects for over a century, the quantification of handed phenomena based on this definition has proven elusive, if not impossible, as manifest in the paradox of chiral connectedness. In this work, we put forward a quantification scheme in which the handedness of an object depends on the direction in which it is viewed. While consistent with familiar chiral notions, such as the right-hand rule, this framework allows objects to be simultaneously right and left handed. We demonstrate this orientation dependence in three different systems—a biomimetic elastic bilayer, a chiral propeller, and optical metamaterial—and find quantitative agreement with chirality pseudotensors whose form we explicitly compute. The use of this approach resolves the existing paradoxes and naturally enables the design of handed metamaterials from symmetry principles.

Macdonald index and chiral algebra

Science.gov (United States)

Song, Jaewon

2017-08-01

For any 4d N = 2 SCFT, there is a subsector described by a 2d chiral algebra. The vacuum character of the chiral algebra reproduces the Schur index of the corresponding 4d theory. The Macdonald index counts the same set of operators as the Schur index, but the former has one more fugacity than the latter. We conjecture a prescription to obtain the Macdonald index from the chiral algebra. The vacuum module admits a filtration, from which we construct an associated graded vector space. From this grading, we conjecture a notion of refined character for the vacuum module of a chiral algebra, which reproduces the Macdonald index. We test this prescription for the Argyres-Douglas theories of type ( A 1 , A 2 n ) and ( A 1 , D 2 n+1) where the chiral algebras are given by Virasoro and \\widehat{su}(2) affine Kac-Moody algebra. When the chiral algebra has more than one family of generators, our prescription requires a knowledge of the generators from the 4d.

Isomer shifts of the octupole doublet in muonic 207Pb

International Nuclear Information System (INIS)

Budick, B.; Anigstein, R.; Kast, J.W.

1980-01-01

Isomer shifts in the doublet 5/2 + , 7/2 + levels in muonic 207 Pb have been measured. The shifts are essentially the same as in the core 3 - collective state. They support the hypothesis that the octupole vibration does not conserve volume. (orig.)

Inert two-Higgs-doublet model strongly coupled to a non-Abelian vector resonance

Science.gov (United States)

Rojas-Abatte, Felipe; Mora, Maria Luisa; Urbina, Jose; Zerwekh, Alfonso R.

2017-11-01

We study the possibility of a dark matter candidate having its origin in an extended Higgs sector which, at least partially, is related to a new strongly interacting sector. More concretely, we consider an i2HDM (i.e., a Type-I two Higgs doublet model supplemented with a Z2 under which the nonstandard scalar doublet is odd) based on the gauge group S U (2 )1×S U (2 )2×U (1 )Y . We assume that one of the scalar doublets and the standard fermion transform nontrivially under S U (2 )1 while the second doublet transforms under S U (2 )2. Our main hypothesis is that standard sector is weakly coupled while the gauge interactions associated to the second group is characterized by a large coupling constant. We explore the consequences of this construction for the phenomenology of the dark matter candidate and we show that the presence of the new vector resonance reduces the relic density saturation region, compared to the usual i2DHM, in the high dark matter mass range. In the collider side, we argue that the mono-Z production is the channel which offers the best chances to manifest the presence of the new vector field. We study the departures from the usual i2HDM predictions and show that the discovery of the heavy vector at the LHC is challenging even in the mono-Z channel since the typical cross sections are of the order of 10-2 fb .

Floquet engineering of Haldane Chern insulators and chiral bosonic phase transitions

Science.gov (United States)

Plekhanov, Kirill; Roux, Guillaume; Le Hur, Karyn

2017-01-01

The realization of synthetic gauge fields has attracted a lot of attention recently in relation to periodically driven systems and the Floquet theory. In ultracold atom systems in optical lattices and photonic networks, this allows one to simulate exotic phases of matter such as quantum Hall phases, anomalous quantum Hall phases, and analogs of topological insulators. In this paper, we apply the Floquet theory to engineer anisotropic Haldane models on the honeycomb lattice and two-leg ladder systems. We show that these anisotropic Haldane models still possess a topologically nontrivial band structure associated with chiral edge modes. Focusing on (interacting) boson systems in s -wave bands of the lattice, we show how to engineer through the Floquet theory, a quantum phase transition (QPT) between a uniform superfluid and a Bose-Einstein condensate analog of Fulde-Ferrell-Larkin-Ovchinnikov states, where bosons condense at nonzero wave vectors. We perform a Ginzburg-Landau analysis of the QPT on the graphene lattice, and compute observables such as chiral currents and the momentum distribution. The results are supported by exact diagonalization calculations and compared with those of the isotropic situation. The validity of high-frequency expansion in the Floquet theory is also tested using time-dependent simulations for various parameters of the model. Last, we show that the anisotropic choice for the effective vector potential allows a bosonization approach in equivalent ladder (strip) geometries.

An N = 2 worldsheet approach to D-branes in bihermitian geometries: I. Chiral and twisted chiral fields

International Nuclear Information System (INIS)

Sevrin, Alexander; Staessens, Wieland; Wijns, Alexander

2008-01-01

We investigate N = (2, 2) supersymmetric nonlinear σ-models in the presence of a boundary. We restrict our attention to the case where the bulk geometry is described by chiral and twisted chiral superfields corresponding to a bihermitian bulk geometry with two commuting complex structures. The D-brane configurations preserving an N = 2 worldsheet supersymmetry are identified. Duality transformations interchanging chiral for twisted chiral fields and vice versa while preserving all supersymmetries are explicitly constructed. We illustrate our results with various explicit examples such as the WZW-model on the Hopf surface S 3 x S 1 . The duality transformations provide e.g new examples of coisotropic A-branes on Kaehler manifolds (which are not necessarily hyper-Kaehler). Finally, by dualizing a chiral and a twisted chiral field to a semi-chiral multiplet, we initiate the study of D-branes in bihermitian geometries where the cokernel of the commutator of the complex structures is non-empty.

Design, construction and commissioning of a simple, low cost permanent magnet quadrupole doublet

International Nuclear Information System (INIS)

Conard, E.M.; Parcell, S.K.; Arnott, D.W.

1999-01-01

In the framework of new beam line developments at the Australian National Medical Cyclotron, a permanent magnet quadrupole doublet was designed and built entirely in house. The design proceeded from the classical work by Halbach et al. but emphasised the 'low cost' aspect by using simple rectangular NdFeB blocks and simple assembly techniques. Numerical simulations using the (2-D) Gemini code were performed to check the field strength and homogeneity predictions of analytical calculations. This paper gives the reasons for the selection of a permanent magnet, the design and construction details of the quadrupole doublet and its field measurement results. (authors)

Development of thermal fractures in two Dutch geothermal doublets

NARCIS (Netherlands)

Loeve, D.; Veldkamp, J.G.; Peters, E.; Wees, J.D.A.M. van

2015-01-01

In the production well of a low-enthalpy geothermal doublet hot water is pumped from reservoirs at about 50-1007deg;C. After passing through a heat exchanger, the cold water is re-injected at about 20-357deg;C in the injection well into the reservoir, which initially has the same temperature as the

Measurements of Narrow Mg II Associated Absorption Doublets with ...

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... The measurement of the variations of absorption lines over time is a good method to study the physical conditions of absorbers. In this paper, we measure the variations of the line strength of 36 narrow Mg II2796, 2803 associated absorption doublets, which are imprinted on 31 quasar spectra with two ...

Laser Writing of Multiscale Chiral Polymer Metamaterials

Directory of Open Access Journals (Sweden)

E. P. Furlani

2012-01-01

Full Text Available A new approach to metamaterials is presented that involves laser-based patterning of novel chiral polymer media, wherein chirality is realized at two distinct length scales, intrinsically at the molecular level and geometrically at a length scale on the order of the wavelength of the incident field. In this approach, femtosecond-pulsed laser-induced two-photon lithography (TPL is used to pattern a photoresist-chiral polymer mixture into planar chiral shapes. Enhanced bulk chirality can be realized by tuning the wavelength-dependent chiral response at both the molecular and geometric level to ensure an overlap of their respective spectra. The approach is demonstrated via the fabrication of a metamaterial consisting of a two-dimensional array of chiral polymer-based L-structures. The fabrication process is described and modeling is performed to demonstrate the distinction between molecular and planar geometric-based chirality and the effects of the enhanced multiscale chirality on the optical response of such media. This new approach to metamaterials holds promise for the development of tunable, polymer-based optical metamaterials with low loss.

The covariant chiral ring

Energy Technology Data Exchange (ETDEWEB)

Bourget, Antoine; Troost, Jan [Laboratoire de Physique Théorique, École Normale Supérieure, 24 rue Lhomond, 75005 Paris (France)

2016-03-23

We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N=(4,4) supersymmetry in two dimensions. For seed target spaces K3 and T{sup 4}, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.

Material failures observed in the Doublet III neutral beamlines

International Nuclear Information System (INIS)

Bailey, E.W.; Colleraine, A.; Doll, D.; Grunloh, H.; Kim, J.; Langhorn, A.; Thurgood, B.

1983-01-01

The Doublet III neutral beam injectors consist of three separable spools two meters in diameter by four meters long overall when assembled. Contained within these spools are the neutralizers, ion dumps, deflecting magnet, calorimeter dumps, cryogenic panels and beam scraping collimators. To date three beamlines are in operation on Doublet III, and the beams have accumulated operating time of approximately 32 months, with the oldest having been in operation for 18 months. During this time operation of DIII with the neutral beam sources has demonstrated the following: 7.8 MW injected neutrals from three beamlines (6 sources), high β (4.5%), and non-circular plasma shape. The sources have also exibited a very reliable injected shot history. Material failures encountered during the operation of DIII N.B. injectors and the solutions to these failures are described. Failures include cracking of the neutralizer exit collimator due to heating cycles, failure of cyropanel support rods due to cooling cycles, failure of the sliding drive of the moveable calorimeter due to friction

Novel electrochemical method for the characterization of the degree of chirality in chiral polyaniline.

Science.gov (United States)

Feng, Zhang; Li, Ma; Yan, Yang; Jihai, Tang; Xiao, Li; Wanglin, Li

2013-01-01

A novel method to indicate the degree of chirality in polyaniline (PANI) was developed. The (D-camphorsulfonic acid)- and (HCl)-PANI-based electrodes exhibited significantly different electrochemical performances in D- and L-Alanine (Ala) aqueous solution, respectively, which can be used for the characterization the optical activity of chiral PANI. Cyclic voltammogram, tafel, and open circuit potential of PANI-based electrodes were measured within D- and L-Ala electrolyte solution, respectively. The open circuit potentials under different reacting conditions were analyzed by Doblhofer model formula, in which [C(+)](poly1)/[C(+)](poly2) was used as a parameter to characterize the degree of chirality in chiral PANI. The results showed that [C(+)](poly1)/[C(+)](poly2) can be increased with increasing concentrations of (1S)-(+)- and (1R)-(-)-10-camphorsulfonic acid. In addition, we detected that appropriate response time and lower temperature are necessary to improve the degree of chirality. Copyright © 2012 Wiley Periodicals, Inc.

Molecular-Level Design of Heterogeneous Chiral Catalysis

International Nuclear Information System (INIS)

Zaera, Francisco

2012-01-01

The following is a proposal to continue our multi-institutional research on heterogeneous chiral catalysis. Our team combines the use of surface-sensitive analytical techniques for the characterization of model systems with quantum and statistical mechanical calculations to interpret experimental data and guide the design of future research. Our investigation focuses on the interrelation among the three main mechanisms by which enantioselectivity can be bestowed to heterogeneous catalysts, namely: (1) by templating chirality via the adsorption of chiral supramolecular assemblies, (2) by using chiral modifiers capable of forming chiral complexes with the reactant and force enantioselective surface reactions, and (3) by forming naturally chiral surfaces using imprinting chiral agents. Individually, the members of our team are leaders in these various aspects of chiral catalysis, but the present program provides the vehicle to generate and exploit the synergies necessary to address the problem in a comprehensive manner. Our initial work has advanced the methodology needed for these studies, including an enantioselective titration procedure to identify surface chiral sites, infrared spectroscopy in situ at the interface between gases or liquids and solids to mimic realistic catalytic conditions, and DFT and Monte Carlo algorithms to simulate and understand chirality on surfaces. The next step, to be funded by the monies requested in this proposal, is to apply those methods to specific problems in chiral catalysis, including the identification of the requirements for the formation of supramolecular surface structures with enantioselective behavior, the search for better molecules to probe the chiral nature of the modified surfaces, the exploration of the transition from supramolecular to one-to-one chiral modification, the correlation of the adsorption characteristics of one-to-one chiral modifiers with their physical properties, in particular with their configuration

Molecular-level Design of Heterogeneous Chiral Catalysts

Energy Technology Data Exchange (ETDEWEB)

Gellman, Andrew John [Carnegie Mellon University; Sholl, David S. [Georgia Institute of Technology; Tysoe, Wilfred T. [University of Wisconsin - Milwaukee; Zaera, Francisco [University of California at Riverside

2013-04-28

Understanding and controlling selectivity is one of the key challenges in heterogeneous catalysis. Among problems in catalytic selectivity enantioselectivity is perhaps the most the most challenging. The primary goal of the project on “Molecular-level Design of Heterogeneous Chiral Catalysts” is to understand the origins of enantioselectivity on chiral heterogeneous surfaces and catalysts. The efforts of the project team include preparation of chiral surfaces, characterization of chiral surfaces, experimental detection of enantioselectivity on such surfaces and computational modeling of the interactions of chiral probe molecules with chiral surfaces. Over the course of the project period the team of PI’s has made some of the most detailed and insightful studies of enantioselective chemistry on chiral surfaces. This includes the measurement of fundamental interactions and reaction mechanisms of chiral molecules on chiral surfaces and leads all the way to rationale design and synthesis of chiral surfaces and materials for enantioselective surface chemistry. The PI’s have designed and prepared new materials for enantioselective adsorption and catalysis. Naturally Chiral Surfaces • Completion of a systematic study of the enantiospecific desorption kinetics of R-3-methylcyclohexanone (R-3-MCHO) on 9 achiral and 7 enantiomeric pairs of chiral Cu surfaces with orientations that span the stereographic triangle. • Discovery of super-enantioselective tartaric acid (TA) and aspartic acid (Asp) decomposition as a result of a surface explosion mechanism on Cu(643)R&S. Systematic study of super-enantiospecific TA and Asp decomposition on five enantiomeric pairs of chiral Cu surfaces. • Initial observation of the enantiospecific desorption of R- and S-propylene oxide (PO) from Cu(100) imprinted with {3,1,17} facets by L-lysine adsorption. Templated Chiral Surfaces • Initial observation of the enantiospecific desorption of R- and S-PO from Pt(111) and Pd(111

Supramolecular Chirality: Solvent Chirality Transfer in Molecular Chemistry and Polymer Chemistry

Directory of Open Access Journals (Sweden)

Michiya Fujiki

2014-08-01

Full Text Available Controlled mirror symmetry breaking arising from chemical and physical origin is currently one of the hottest issues in the field of supramolecular chirality. The dynamic twisting abilities of solvent molecules are often ignored and unknown, although the targeted molecules and polymers in a fluid solution are surrounded by solvent molecules. We should pay more attention to the facts that mostly all of the chemical and physical properties of these molecules and polymers in the ground and photoexcited states are significantly influenced by the surrounding solvent molecules with much conformational freedom through non-covalent supramolecular interactions between these substances and solvent molecules. This review highlights a series of studies that include: (i historical background, covering chiral NaClO3 crystallization in the presence of d-sugars in the late 19th century; (ii early solvent chirality effects for optically inactive chromophores/fluorophores in the 1960s–1980s; and (iii the recent development of mirror symmetry breaking from the corresponding achiral or optically inactive molecules and polymers with the help of molecular chirality as the solvent use quantity.

Is Supramolecular Filament Chirality the Underlying Cause of Major Morphology Differences in Amyloid Fibrils?

Science.gov (United States)

2015-01-01

The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for “normal” left-hand-helical filaments and below pH 2 for “reversed” right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218–289) prion, and a short polypeptide fragment of transthyretin, TTR (105–115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases. PMID:24484302

Is supramolecular filament chirality the underlying cause of major morphology differences in amyloid fibrils?

Science.gov (United States)

Kurouski, Dmitry; Lu, Xuefang; Popova, Ludmila; Wan, William; Shanmugasundaram, Maruda; Stubbs, Gerald; Dukor, Rina K; Lednev, Igor K; Nafie, Laurence A

2014-02-12

The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for "normal" left-hand-helical filaments and below pH 2 for "reversed" right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218-289) prion, and a short polypeptide fragment of transthyretin, TTR (105-115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases.

Chirality-induced magnon transport in AA-stacked bilayer honeycomb chiral magnets.

Science.gov (United States)

Owerre, S A

2016-11-30

In this Letter, we study the magnetic transport in AA-stacked bilayer honeycomb chiral magnets coupled either ferromagnetically or antiferromagnetically. For both couplings, we observe chirality-induced gaps, chiral protected edge states, magnon Hall and magnon spin Nernst effects of magnetic spin excitations. For ferromagnetically coupled layers, thermal Hall and spin Nernst conductivities do not change sign as function of magnetic field or temperature similar to single-layer honeycomb ferromagnetic insulator. In contrast, for antiferromagnetically coupled layers, we observe a sign change in the thermal Hall and spin Nernst conductivities as the magnetic field is reversed. We discuss possible experimental accessible honeycomb bilayer quantum materials in which these effects can be observed.

Asymmetric synthesis using chiral-encoded metal

Science.gov (United States)

Yutthalekha, Thittaya; Wattanakit, Chularat; Lapeyre, Veronique; Nokbin, Somkiat; Warakulwit, Chompunuch; Limtrakul, Jumras; Kuhn, Alexander

2016-08-01

The synthesis of chiral compounds is of crucial importance in many areas of society and science, including medicine, biology, chemistry, biotechnology and agriculture. Thus, there is a fundamental interest in developing new approaches for the selective production of enantiomers. Here we report the use of mesoporous metal structures with encoded geometric chiral information for inducing asymmetry in the electrochemical synthesis of mandelic acid as a model molecule. The chiral-encoded mesoporous metal, obtained by the electrochemical reduction of platinum salts in the presence of a liquid crystal phase and the chiral template molecule, perfectly retains the chiral information after removal of the template. Starting from a prochiral compound we demonstrate enantiomeric excess of the (R)-enantiomer when using (R)-imprinted electrodes and vice versa for the (S)-imprinted ones. Moreover, changing the amount of chiral cavities in the material allows tuning the enantioselectivity.

Chiral relay: a novel strategy for the control and amplification of enantioselectivity in chiral Lewis acid promoted reactions.

Science.gov (United States)

Corminboeuf, Olivier; Quaranta, Laura; Renaud, Philippe; Liu, Mei; Jasperse, Craig P; Sibi, Mukund P

2003-01-03

Chiral Lewis acid catalysis has emerged as one of the premiere method to control stereochemistry. Much effort has gone into the design of superior ligands with increasing steric extension to shield distant reactive sites. We report here an alternative and complementary approach based on a "chiral relay". This strategy focuses on the improved design of achiral templates which may relay and amplify the stereochemistry from ligands. The essence of this strategy is that the chiral Lewis acid would effectively convert an achiral template into a chiral non-racemic template. This approach combines the advantages of enantioselective catalysis (substoichiometric amount of the chiral inducer) with the ones of chiral auxiliary control (efficient and predictable stereocontrol).

Significant Enhancement of the Chiral Correlation Length in Nematic Liquid Crystals by Gold Nanoparticle Surfaces Featuring Axially Chiral Binaphthyl Ligands.

Science.gov (United States)

Mori, Taizo; Sharma, Anshul; Hegmann, Torsten

2016-01-26

Chirality is a fundamental scientific concept best described by the absence of mirror symmetry and the inability to superimpose an object onto its mirror image by translation and rotation. Chirality is expressed at almost all molecular levels, from single molecules to supramolecular systems, and present virtually everywhere in nature. Here, to explore how chirality propagates from a chiral nanoscale surface, we study gold nanoparticles functionalized with axially chiral binaphthyl molecules. In particular, we synthesized three enantiomeric pairs of chiral ligand-capped gold nanoparticles differing in size, curvature, and ligand density to tune the chirality transfer from nanoscale solid surfaces to a bulk anisotropic liquid crystal medium. Ultimately, we are examining how far the chirality from a nanoparticle surface reaches into a bulk material. Circular dichroism spectra of the gold nanoparticles decorated with binaphthyl thiols confirmed that the binaphthyl moieties form a cisoid conformation in isotropic organic solvents. In the chiral nematic liquid crystal phase, induced by dispersing the gold nanoparticles into an achiral anisotropic nematic liquid crystal solvent, the binaphthyl moieties on the nanoparticle surface form a transoid conformation as determined by imaging the helical twist direction of the induced cholesteric phase. This suggests that the ligand density on the nanoscale metal surfaces provides a dynamic space to alter and adjust the helicity of binaphthyl derivatives in response to the ordering of the surrounding medium. The helical pitch values of the induced chiral nematic phase were determined, and the helical twisting power (HTP) of the chiral gold nanoparticles calculated to elucidate the chirality transfer efficiency of the binaphthyl ligand capped gold nanoparticles. Remarkably, the HTP increases with increasing diameter of the particles, that is, the efficiency of the chirality transfer of the binaphthyl units bound to the nanoparticle

Symmetry, structure, and dynamics of monoaxial chiral magnets

International Nuclear Information System (INIS)

Togawa, Yoshihiko; Kousaka, Yusuke; Inoue, Katsuya; Kishine, Jun-ichiro

2016-01-01

Nontrivial spin orders with magnetic chirality emerge in a particular class of magnetic materials with structural chirality, which are frequently referred to as chiral magnets. Various interesting physical properties are expected to be induced in chiral magnets through the coupling of chiral magnetic orders with conduction electrons and electromagnetic fields. One promising candidate for achieving these couplings is a chiral spin soliton lattice. Here, we review recent experimental observations mainly carried out on the monoaxial chiral magnetic crystal CrNb_3S_6 via magnetic imaging using electron, neutron, and X-ray beams and magnetoresistance measurements, together with the strategy for synthesizing chiral magnetic materials and underlying theoretical backgrounds. The chiral soliton lattice appears under a magnetic field perpendicular to the chiral helical axis and is very robust and stable with phase coherence on a macroscopic length scale. The tunable and topological nature of the chiral soliton lattice gives rise to nontrivial physical properties. Indeed, it is demonstrated that the interlayer magnetoresistance scales to the soliton density, which plays an essential role as an order parameter in chiral soliton lattice formation, and becomes quantized with the reduction of the system size. These interesting features arising from macroscopic phase coherence unique to the chiral soliton lattice will lead to the exploration of routes to a new paradigm for applications in spin electronics using spin phase coherence. (author)

Penguin effects induced by the two-Higgs-doublet model and charmless B-meson decays

International Nuclear Information System (INIS)

Davies, A.J.; Joshi, G.C.; Matsuda, M.

1991-01-01

Nonstandard physical effects through the penguin diagram induced by the charged Higgs scalar contribution in the two-Higgs-doublet model are analysed. Since non-leptonic B-decay processes to final states consisting of s+s+anti s are induced only through the penguin diagram they are important tests of such contributions. We compare these decays including the non-standard two-Higgs-doublet contribution with the standard model results, which arise from the magnetic gluon transistion term. The charged Higgs contribution can give a sizable enhancement to the branching fraction of B-meson charmless decay. (orig.)

The influence of facies heterogeneity on the doublet performance in low-enthalpy geothermal sedimentary reservoirs

DEFF Research Database (Denmark)

Crooijmans, R. A.; Willems, C. J L; Nick, Hamid

2016-01-01

A three-dimensional model is used to study the influence of facies heterogeneity on energy production under different operational conditions of low-enthalpy geothermal doublet systems. Process-based facies modelling is utilised for the Nieuwerkerk sedimentary formation in the West Netherlands Basin...... and the energy recovery rate for different discharge rates and the production temperature (Tmin) above which the doublet is working. With respect to the results, we propose a design model to estimate the life time and energy recovery rate of the geothermal doublet. The life time is estimated as a function of N....../G, Tmin and discharge rate, while the design model for the energy recovery rate is only a function of N/G and Tmin. Both life time and recovery show a positive relation with an increasing N/G. Further our results suggest that neglecting details of process-based facies modelling may lead to significant...

Chirality: a relational geometric-physical property.

Science.gov (United States)

Gerlach, Hans

2013-11-01

The definition of the term chirality by Lord Kelvin in 1893 and 1904 is analyzed by taking crystallography at that time into account. This shows clearly that chirality is a relational geometric-physical property, i.e., two relations between isometric objects are possible: homochiral or heterochiral. In scientific articles the relational term chirality is often mistaken for the two valued measure for the individual (absolute) sense of chirality, an arbitrary attributive term. © 2013 Wiley Periodicals, Inc.

Light-front realization of chiral symmetry breaking

International Nuclear Information System (INIS)

Itakura, Kazunori; Maedan, Shinji

2001-01-01

We discuss a description of chiral symmetry breaking in the light-front (LF) formalism. Based on careful analyses of several modes, we give clear answers to the following three fundamental questions: (i) What is the difference between the LF chiral transformation and the ordinary chiral transformation? (ii) How does a gap equation for the chiral condensate emerge? (iii) What is the consequence of the coexistence of a nonzero chiral condensate and the trivial Fock vacuum? The answer to Question (i) is given through a classical analysis of each model. Question (ii) is answered based on our recognition of the importance of characteristic constraints, such as the zero-mode and fermionic constraints. Question (iii) is intimately related to another important problem, reconciliation of the nonzero chiral condensate ≠ 0 and the invariance of the vacuum under the LF chiral transformation Q 5 LF | 0> = 0. This and Question (iii) are understood in terms of the modified chiral transformation laws of the dependent variables. The characteristic ways in which the chiral symmetry breaking is realized are that the chiral charge Q 5 LF is no longer conserved and that the transformation of the scalar and pseudoscalar fields is modified. We also discuss other outcomes, such as the light-cone wave function of the pseudoscalar meson in the Nambu-Jona-Lasinio model. (author)

Chiral stationary phase optimized selectivity liquid chromatography: A strategy for the separation of chiral isomers.

Science.gov (United States)

Hegade, Ravindra Suryakant; De Beer, Maarten; Lynen, Frederic

2017-09-15

Chiral Stationary-Phase Optimized Selectivity Liquid Chromatography (SOSLC) is proposed as a tool to optimally separate mixtures of enantiomers on a set of commercially available coupled chiral columns. This approach allows for the prediction of the separation profiles on any possible combination of the chiral stationary phases based on a limited number of preliminary analyses, followed by automated selection of the optimal column combination. Both the isocratic and gradient SOSLC approach were implemented for prediction of the retention times for a mixture of 4 chiral pairs on all possible combinations of the 5 commercial chiral columns. Predictions in isocratic and gradient mode were performed with a commercially available and with an in-house developed Microsoft visual basic algorithm, respectively. Optimal predictions in the isocratic mode required the coupling of 4 columns whereby relative deviations between the predicted and experimental retention times ranged between 2 and 7%. Gradient predictions led to the coupling of 3 chiral columns allowing baseline separation of all solutes, whereby differences between predictions and experiments ranged between 0 and 12%. The methodology is a novel tool allowing optimizing the separation of mixtures of optical isomers. Copyright © 2017 Elsevier B.V. All rights reserved.

LHC phenomenology of composite 2-Higgs doublet models

Energy Technology Data Exchange (ETDEWEB)

De Curtis, Stefania [University of Florence, Department of Physics and Astronomy, Sesto Fiorentino (Italy); INFN, Sezione di Firenze (Italy); Moretti, Stefano; Yagyu, Kei; Yildirim, Emine [University of Southampton, School of Physics and Astronomy, Southampton (United Kingdom)

2017-08-15

We investigate the phenomenology of Composite 2-Higgs doublet models (C2HDMs) of various Yukawa types based on the global symmetry breaking SO(6) → SO(4) x SO(2). The kinetic part and the Yukawa Lagrangian are constructed in terms of the pseudo Nambu-Goldstone Boson (pNGB) matrix and a 6-plet of fermions under SO(6). The scalar potential is assumed to be the same as that of the Elementary 2-Higgs doublet model (E2HDM) with a softly broken discrete Z{sub 2} symmetry. We then discuss the phenomenological differences between the E2HDM and C2HDM by focusing on the deviations from standard model (SM) couplings of the discovered Higgs state (h) as well as on the production cross sections and branching ratios (BRs) at the large Hadron collider (LHC) of extra Higgs bosons. We find that, even if the same deviation in the hVV (V = W,Z) coupling is assumed in the two scenarios, there appear significant differences between the E2HDM and C2HDM from the structure of the Yukawa couplings, so that production and decay features of extra Higgs bosons can be used to distinguish between the two scenarios. (orig.)

Hadron properties in chiral sigma model

International Nuclear Information System (INIS)

Shen Hong

2005-01-01

The modification of hadron masses in nuclear medium is studied by using the chiral sigma model, which is extended to generate the omega meson mass by the sigma condensation in the vacuum in the same way as the nucleon mass. The chiral sigma model provides proper equilibrium properties of nuclear matter. It is shown that the effective masses of both nucleons and omega mesons decrease in nuclear medium, while the effective mass of sigma mesons increases oat finite density in the chiral sigma model. The results obtained in the chiral sigma model are compared with those obtained in the Walecka model, which includes sigma and omega mesons in a non-chiral fashion. (author)

Chiral recognition in separation science: an overview.

Science.gov (United States)

Scriba, Gerhard K E

2013-01-01

Chiral recognition phenomena play an important role in nature as well as analytical separation sciences. In separation sciences such as chromatography and capillary electrophoresis, enantiospecific interactions between the enantiomers of an analyte and the chiral selector are required in order to observe enantioseparations. Due to the large structural variety of chiral selectors applied, different mechanisms and structural features contribute to the chiral recognition process. This chapter briefly illustrates the current models of the enantiospecific recognition on the structural basics of various chiral selectors.

No chiral truncation of quantum log gravity?

Science.gov (United States)

Andrade, Tomás; Marolf, Donald

2010-03-01

At the classical level, chiral gravity may be constructed as a consistent truncation of a larger theory called log gravity by requiring that left-moving charges vanish. In turn, log gravity is the limit of topologically massive gravity (TMG) at a special value of the coupling (the chiral point). We study the situation at the level of linearized quantum fields, focussing on a unitary quantization. While the TMG Hilbert space is continuous at the chiral point, the left-moving Virasoro generators become ill-defined and cannot be used to define a chiral truncation. In a sense, the left-moving asymptotic symmetries are spontaneously broken at the chiral point. In contrast, in a non-unitary quantization of TMG, both the Hilbert space and charges are continuous at the chiral point and define a unitary theory of chiral gravity at the linearized level.

High-scale validity of a two-Higgs-doublet scenario: metastability included

Energy Technology Data Exchange (ETDEWEB)

Chakrabarty, Nabarun; Mukhopadhyaya, Biswarup [Harish-Chandra Research Institute, Regional Centre for Accelerator-based Particle Physics, Allahabad (India)

2017-03-15

We identify regions in a Type-II two-Higgs-doublet model which correspond to a metastable electroweak vacuum with lifetime larger than the age of the universe. We analyse scenarios which retain perturbative unitarity up to grand unification and Planck scales. Each point in the parameter space is restricted using data from the Large Hadron Collider (LHC) as well as flavour and precision electroweak constraints. We find that substantial regions of the parameter space are thus identified as corresponding to metastability, which complement the allowed regions for absolute stability, for top quark mass at the high as well as low end of its currently allowed range. Thus, a two-Higgs-doublet scenario with the electroweak vacuum, either stable or metastable, can sail through all the way up to the Planck scale without facing any contradiction. (orig.)

Direct Detection of Hardly Detectable Hidden Chirality of Hydrocarbons and Deuterated Isotopomers by a Helical Polyacetylene through Chiral Amplification and Memory.

Science.gov (United States)

Maeda, Katsuhiro; Hirose, Daisuke; Okoshi, Natsuki; Shimomura, Kouhei; Wada, Yuya; Ikai, Tomoyuki; Kanoh, Shigeyoshi; Yashima, Eiji

2018-03-07

We report the first direct chirality sensing of a series of chiral hydrocarbons and isotopically chiral compounds (deuterated isotopomers), which are almost impossible to detect by conventional optical spectroscopic methods, by a stereoregular polyacetylene bearing 2,2'-biphenol-derived pendants. The polyacetylene showed a circular dichroism due to a preferred-handed helix formation in response to the hardly detectable hidden chirality of saturated tertiary or chiroptical quaternary hydrocarbons, and deuterated isotopomers. In sharp contrast to the previously reported sensory systems, the chirality detection by the polyacetylene relies on an excess one-handed helix formation induced by the chiral hydrocarbons and deuterated isotopomers via significant amplification of the chirality followed by its static memory, through which chiral information on the minute and hidden chirality can be stored as an excess of a single-handed helix memory for a long time.

Hydrodynamic and Thermophoretic Effects on the Supramolecular Chirality of Pyrene-Derived Nanosheets.

Science.gov (United States)

Micali, Norberto; Vybornyi, Mykhailo; Mineo, Placido; Khorev, Oleg; Häner, Robert; Villari, Valentina

2015-06-22

Chiroptical properties of two-dimensional (2D) supramolecular assemblies (nanosheets) of achiral, charged pyrene trimers (Py3 ) are rendered chiral by asymmetric physical perturbations. Chiral stimuli in a cuvette can originate either from controlled temperature gradients or by very gentle stirring. The chiroptical activity strongly depends on the degree of supramolecular order of the nanosheets, which is easily controlled by the method of preparation. The high degree of structural order ensures strong cooperative effects within the aggregates, rendering them more susceptible to external stimuli. The samples prepared by using slow thermal annealing protocols are both CD and LD active (in stagnant and stirred solutions), whereas for isothermally aged samples chiroptical activity was in all cases undetectable. In the case of temperature gradients, the optical activity of 2D assemblies could be recorded for a stagnant solution due to migration of the aggregates from the hottest to the coldest regions of the system. However, a considerably stronger exciton coupling, coinciding with the J-band of the interacting pyrenes, is developed upon subtle vortexing (0.5 Hz, 30 rpm) of the aqueous solution of the nanosheets. The sign of the exciton coupling is inverted upon switching between clockwise and counter-clockwise rotation. The supramolecular chirality is evidenced by the appearance of CD activity. To exclude artefacts from proper CD spectra, the contribution from LD to the observed CD was determined. The data suggest that the aggregates experience asymmetrical deformation and alignment effects because of the presence of chiral flows. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Doublet vs. FODO structure: beam dynamics and layout

CERN Document Server

Eshraqi, M; CERN. Geneva. BE Department

2010-01-01

A FoDo (singlet) structure is designed for the CERN Superconducting Proton LINAC. This architecture is compared to the baseline (doublet) architecture of SPL on the basis of its beam dynamics performance and the required investment. The sensitivity of both layouts to quadrupole gradient errors and misalignment is checked and a correction scheme for beam steering is proposed. Finally a single quad beam dilution scheme is studied and designed for the pilot beam dump.

Chiral anomaly, Berry phase, and chiral kinetic theory from worldlines in quantum field theory

Science.gov (United States)

Mueller, Niklas; Venugopalan, Raju

2018-03-01

In previous work, we outlined a worldline framework that can be used for systematic computations of the chiral magnetic effect (CME) in ultrarelativistic heavy-ion collisions. Towards this end, we first expressed the real part of the fermion determinant in the QCD effective action as a supersymmetric worldline action of spinning, colored, Grassmanian point particles in background gauge fields, with equations of motion that are covariant generalizations of the Bargmann-Michel-Telegdi and Wong equations. The chiral anomaly, in contrast, arises from the phase of the fermion determinant. Remarkably, the latter too can be expressed as a point particle worldline path integral, which can be employed to derive the anomalous axial vector current. We will show here how Berry's phase can be obtained in a consistent nonrelativistic adiabatic limit of the real part of the fermion determinant. Our work provides a general first principles demonstration that the topology of Berry's phase is distinct from that of the chiral anomaly confirming prior arguments by Fujikawa in specific contexts. This suggests that chiral kinetic treatments of the CME in heavy-ion collisions that include Berry's phase alone are incomplete. We outline the elements of a worldline covariant relativistic chiral kinetic theory that captures the physics of how the chiral current is modified by many-body scattering and topological fluctuations.

Chiral dynamics with (nonstrange quarks

Directory of Open Access Journals (Sweden)

Kubis Bastian

2017-01-01

Full Text Available We review the results and achievements of the project B.3. Topics addressed include pion photoproduction off the proton and off deuterium, three-flavor chiral perturbation theory studies, chiral symmetry tests in Goldstone boson decays, the development of unitarized chiral perturbation theory to next-to-leading order, the two-pole structure of the Λ(1405, the dynamical generation of the lowest S11 resonances, the theory of hadronic atoms and its application to various systems, precision studies in light-meson decays based on dispersion theory, the Roy–Steiner analysis of pion–nucleon scattering, a high-precision extraction of the elusive pion–nucleon σ-term, and aspects of chiral dynamics in few-nucleon systems.

Enantiomeric Separation of 1-(Benzofuran-2-yl)alkylamines on Chiral Stationary Phases Based on Chiral Crown Ethers

International Nuclear Information System (INIS)

Park, Soohyun; Kim, Sang Jun; Hyun, Myung Ho

2012-01-01

Optically active chiral amines are important as building blocks for pharmaceuticals and as scaffolds for chiral ligands and, consequently, many efforts have been devoted to the development of efficient methods for their preparation. For example, reduction of amine precursors with chiral catalysts, enzymatic kinetic resolution or dynamic kinetic resolution of racemic amines and the direct amination of ketones with transaminases have been developed as the efficient methods for the preparation of optically active chiral amines. During the process of developing or utilizing optically active chiral amines, the methods for the determination of their enantiomeric composition are essential. Among various methods, liquid chromatographic resolution of enantiomers on chiral stationary phases (CSPs) have been known to be one of the most accurate and economic means for the determination of the enantiomeric composition of optically active chiral compounds. Especially, CSPs based on chiral crown ethers have been successfully used for the resolution of racemic primary amines. For example, CSPs based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (CSP 1, Figure 1) or (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 (CSP 2 and CSP 3, Figure 1) have been known to be quite effective for the resolution of cyclic and non-cyclic amines, various fluoroquinolone antibacterials containing a primary amino group, tocainide (antiarrhythmic agent) and its analogues, aryl-a-amino ketones and 3-amino-1,4-benzodiazepin-2-ones

Is there chirality in atomic nuclei?

International Nuclear Information System (INIS)

Meng Jie

2009-01-01

Static chiral symmetries are common in nature, for example, the macroscopic spirals of snail shells, the microscopic handedness of certain molecules, and human hands. The concept of chirality in atomic nuclei was first proposed in 1997, and since then many efforts have been made to understand chiral symmetry and its spontaneous breaking in atomic nuclei. Recent theoretical and experimental progress in the verification of chirality in atomic nuclei will be reviewed, together with a discussion of the problems that await to be solved in the future. (authors)

Magnitude of Higgs-boson-exchange CP violation in two-doublet models with large tanβ

International Nuclear Information System (INIS)

Barr, S.M.

1993-01-01

CP violation in neutral Higgs-boson exchange is studied in two-doublet models in an expansion in (1/tan 2 β). The typical magnitude of various CP-violating quantities is found for large tanβ. In particular the electric dipole moment (EDM) of the electron and the coefficient c S of the CP-violating electron-nucleon scalar-pseudoscalar operator are examined and it is found that in a simple class of two-doublet models c S /d e is typically O(tan 2 β). Therefore c S is more important than d e for the EDM's of diamagnetic atoms and molecules (Hg, Xe, TlF) typically if tanβ approx-gt 5, and for paramagnetic atoms (Cs, Tl) if tanβ approx-gt 15. The dependence on tanβ of the various contributions to the neutron EDM including the Weinberg three-gluon operator, and the dependence on tanβ of the top-quark EDM are also discussed. Supersymmetric and three-doublet models are also considered

Influence of Chirality in Ordered Block Copolymer Phases

Science.gov (United States)

Prasad, Ishan; Grason, Gregory

2015-03-01

Block copolymers are known to assemble into rich spectrum of ordered phases, with many complex phases driven by asymmetry in copolymer architecture. Despite decades of study, the influence of intrinsic chirality on equilibrium mesophase assembly of block copolymers is not well understood and largely unexplored. Self-consistent field theory has played a major role in prediction of physical properties of polymeric systems. Only recently, a polar orientational self-consistent field (oSCF) approach was adopted to model chiral BCP having a thermodynamic preference for cholesteric ordering in chiral segments. We implement oSCF theory for chiral nematic copolymers, where segment orientations are characterized by quadrupolar chiral interactions, and focus our study on the thermodynamic stability of bi-continuous network morphologies, and the transfer of molecular chirality to mesoscale chirality of networks. Unique photonic properties observed in butterfly wings have been attributed to presence of chiral single-gyroid networks, this has made it an attractive target for chiral metamaterial design.

Anisotropy and Strong-Coupling Effects on the Collective Mode Spectrum of Chiral Superconductors: Application to Sr₂RuO₄

Directory of Open Access Journals (Sweden)

James Avery Sauls

2015-06-01

Full Text Available Recent theories of Sr2RuO4 based on the interplay of strong interactions, spin-orbit coupling and multi-band anisotropy predict chiral or helical ground states with strong anisotropy of the pairing states, with deep minima in the excitation gap, as well as strong phase anisotropy for the chiral ground state. We develop time-dependent mean field theory to calculate the Bosonic spectrum for the class of 2D chiral superconductors spanning 3He-A to chiral superconductors with strong anisotropy. Chiral superconductors support a pair of massive Bosonic excitations of the time-reversed pairs labeled by their parity under charge conjugation. These modes are degenerate for 2D 3He-A. Crystal field anisotropy lifts the degeneracy. Strong anisotropy also leads to low-lying Fermions, and thus to channels for the decay of the Bosonic modes. Selection rules and phase space considerations lead to large asymmetries in the lifetimes and hybridization of the Bosonic modes with the continuum of un-bound Fermion pairs. We also highlight results for the excitation of the Bosonic modes by microwave radiation that provide clear signatures of the Bosonic modes of an anisotropic chiral ground state.

Chiral four-membered cyclic nitrones; asymmetric induction in the (4+2)-cycloaddition reaction of chiral ynamines and nitroalkenes

NARCIS (Netherlands)

van Elburg, P.A.; Honig, G.W.N.; Reinhoudt, David

1987-01-01

Chiral four-membered cyclic nitrones were synthesized by the asymmetric (4+2)-cycloaddition of nitroalkenes 1 and chiral ynamines 2. The subsequent stereoselective addition of nucleophiles to these nitrones enabled the synthesis of chiral N-hydroxyazetidines.

Precision lifetime measurements of Ar II 4p doublet levels

International Nuclear Information System (INIS)

Marger, D.; Schmoranzer, H.

1990-01-01

The lifetimes of the Ar II 4p doublet fine-structure levels 4p 2 D 0 5/2 , 4p' 2 F 0 5/2 and 4p' 2 F 0 7/2 were measured by beam-dye laser spectroscopy. The experimental uncertainty was reduced to below 1%. (orig.)

Variational approach to chiral quark models

Energy Technology Data Exchange (ETDEWEB)

Futami, Yasuhiko; Odajima, Yasuhiko; Suzuki, Akira

1987-03-01

A variational approach is applied to a chiral quark model to test the validity of the perturbative treatment of the pion-quark interaction based on the chiral symmetry principle. It is indispensably related to the chiral symmetry breaking radius if the pion-quark interaction can be regarded as a perturbation.

Some aspects of chirality: Fermion masses and chiral p-forms

Energy Technology Data Exchange (ETDEWEB)

Kleppe, A

1997-05-01

The properties of fermion mass matrices are investigated from different points of view, both within the minimal Standard Model and in extensions of the model. It is shown how mass matrix invariants are used to define the measurables of the quark mixing matrix as invariant functions of the mass matrices. One model is presented where the family pattern is suggested to originate from a kind of mass scaling. A Lagrangian density is defined for an entire charge sector, such that the existence of a Dirac field with mass m{sub 0} implies the existence of other Dirac fields where the corresponding quanta have masses Rm{sub 0}, R{sup 2}m{sub 0}, .. which are obtained by a discrete scale transformation. This suggests a certain type of democratic fermion mass matrices. Also extensions of the minimal Standard Model are investigated, obtained by including right-handed neutrinos in the model. The Standard Model extended by two right-handed neutrinos gives rise to a mass spectrum with two massive and three massless neutrinos. The phenomenological consequences of this model are discussed. The neutrino mass matrix in such a scheme has what is defined as a democratic texture. They are studied for the cases with two and three right-handed neutrinos, resp. The chiral fields that we find in the Standard Model have certain similarities with self-dual fields. Among other things, both chiral and self-dual fields suffer species doubling on the lattice. Chiral p-forms are self-dual fields that appear in twice odd dimensions. Chiral p-forms violate manifest covariance, in the same sense as manifest covariance is violated by non-covariant gauges in electrodynamics. It is shown that a covariant action can nevertheless be formulated for chiral p-forms, by introducing an infinite set of gauge fields in a carefully controlled way.

Some aspects of chirality: Fermion masses and chiral p-forms

International Nuclear Information System (INIS)

Kleppe, A.

1997-05-01

The properties of fermion mass matrices are investigated from different points of view, both within the minimal Standard Model and in extensions of the model. It is shown how mass matrix invariants are used to define the measurables of the quark mixing matrix as invariant functions of the mass matrices. One model is presented where the family pattern is suggested to originate from a kind of mass scaling. A Lagrangian density is defined for an entire charge sector, such that the existence of a Dirac field with mass m 0 implies the existence of other Dirac fields where the corresponding quanta have masses Rm 0 , R 2 m 0 , .. which are obtained by a discrete scale transformation. This suggests a certain type of democratic fermion mass matrices. Also extensions of the minimal Standard Model are investigated, obtained by including right-handed neutrinos in the model. The Standard Model extended by two right-handed neutrinos gives rise to a mass spectrum with two massive and three massless neutrinos. The phenomenological consequences of this model are discussed. The neutrino mass matrix in such a scheme has what is defined as a democratic texture. They are studied for the cases with two and three right-handed neutrinos, resp. The chiral fields that we find in the Standard Model have certain similarities with self-dual fields. Among other things, both chiral and self-dual fields suffer species doubling on the lattice. Chiral p-forms are self-dual fields that appear in twice odd dimensions. Chiral p-forms violate manifest covariance, in the same sense as manifest covariance is violated by non-covariant gauges in electrodynamics. It is shown that a covariant action can nevertheless be formulated for chiral p-forms, by introducing an infinite set of gauge fields in a carefully controlled way

Chirality effect in disordered graphene ribbon junctions

International Nuclear Information System (INIS)

Long Wen

2012-01-01

We investigate the influence of edge chirality on the electronic transport in clean or disordered graphene ribbon junctions. By using the tight-binding model and the Landauer-Büttiker formalism, the junction conductance is obtained. In the clean sample, the zero-magnetic-field junction conductance is strongly chirality-dependent in both unipolar and bipolar ribbons, whereas the high-magnetic-field conductance is either chirality-independent in the unipolar or chirality-dependent in the bipolar ribbon. Furthermore, we study the disordered sample in the presence of magnetic field and find that the junction conductance is always chirality-insensitive for both unipolar and bipolar ribbons with adequate disorders. In addition, the disorder-induced conductance plateaus can exist in all chiral bipolar ribbons provided the disorder strength is moderate. These results suggest that we can neglect the effect of edge chirality in fabricating electronic devices based on the magnetotransport in a disordered graphene ribbon. (paper)

Chiral topological insulator of magnons

Science.gov (United States)

Li, Bo; Kovalev, Alexey A.

2018-05-01

We propose a magnon realization of 3D topological insulator in the AIII (chiral symmetry) topological class. The topological magnon gap opens due to the presence of Dzyaloshinskii-Moriya interactions. The existence of the topological invariant is established by calculating the bulk winding number of the system. Within our model, the surface magnon Dirac cone is protected by the sublattice chiral symmetry. By analyzing the magnon surface modes, we confirm that the backscattering is prohibited. By weakly breaking the chiral symmetry, we observe the magnon Hall response on the surface due to opening of the gap. Finally, we show that by changing certain parameters, the system can be tuned between the chiral topological insulator, three-dimensional magnon anomalous Hall, and Weyl magnon phases.

Chiralities of spiral waves and their transitions.

Science.gov (United States)

Pan, Jun-ting; Cai, Mei-chun; Li, Bing-wei; Zhang, Hong

2013-06-01

The chiralities of spiral waves usually refer to their rotation directions (the turning orientations of the spiral temporal movements as time elapses) and their curl directions (the winding orientations of the spiral spatial geometrical structures themselves). Traditionally, they are the same as each other. Namely, they are both clockwise or both counterclockwise. Moreover, the chiralities are determined by the topological charges of spiral waves, and thus they are conserved quantities. After the inwardly propagating spirals were experimentally observed, the relationship between the chiralities and the one between the chiralities and the topological charges are no longer preserved. The chiralities thus become more complex than ever before. As a result, there is now a desire to further study them. In this paper, the chiralities and their transition properties for all kinds of spiral waves are systemically studied in the framework of the complex Ginzburg-Landau equation, and the general relationships both between the chiralities and between the chiralities and the topological charges are obtained. The investigation of some other models, such as the FitzHugh-Nagumo model, the nonuniform Oregonator model, the modified standard model, etc., is also discussed for comparison.

Online sample concentration in partial-filling chiral electrokinetic chromatography – mass spectrometry.

Science.gov (United States)

Wuethrich, Alain; Haddad, Paul R; Quirino, Joselito P

2014-11-01

The concentration sensitivity of a racemic drug (chlorpheniramine maleate) in chiral capillary electrophoresis with electrospray ionization – mass spectrometric detection was improved ~500-fold via stacking. Enantiomeric separation was achieved through the use of a neutral chiral pseudostationary phase (2-hydroxpropyl-β-cyclodextrin), untreated fused-silica capillaries, and the application of a partial-filling technique to prevent the pseudostationary phase from entering the detector. A concentration factor of 50 resulted from field-enhanced sample injection(FESI). However, the higher concentration factor was achieved by combining FESI with micelle-to-solvent stacking (MSS) to increase sample load and focus the analyte band. MSS was achieved by injection of an ammonium lauryl sulfate micellar plug prior to sample injection. The sample diluent was a 20-fold dilution of the background electrolyte (50 mM ammonium acetate, pH 3.5) with 60% acetonitrile. This methodology provided a limit of detection (LOD) of as low as 5 ng/ml of the racemate.

Enantioselective Biotransformation of Chiral Persistent Organic Pollutants.

Science.gov (United States)

Zhang, Ying; Ye, Jing; Liu, Min

2017-01-01

Enantiomers of chiral compounds commonly undergo enantioselective transformation in most biologically mediated processes. As chiral persistent organic pollutants (POPs) are extensively distributed in the environment, differences between enantiomers in biotransformation should be carefully considered to obtain exact enrichment and specific health risks. This review provides an overview of in vivo biotransformation of chiral POPs currently indicated in the Stockholm Convention and their chiral metabolites. Peer-reviewed journal articles focused on the research question were thoroughly searched. A set of inclusion and exclusion criteria were developed to identify relevant studies. We mainly compared the results from different animal models under controlled laboratory conditions to show the difference between enantiomers in terms of distinct transformation potential. Interactions with enzymes involved in enantioselective biotransformation, especially cytochrome P450 (CYP), were discussed. Further research areas regarding this issue were proposed. Limited evidence for a few POPs has been found in 30 studies. Enantioselective biotransformation of α-hexachlorocyclohexane (α-HCH), chlordane, dichlorodiphenyltrichloroethane (DDT), heptachlor, hexabromocyclododecane (HBCD), polychlorinated biphenyls (PCBs), and toxaphene, has been investigated using laboratory mammal, fish, bird, and worm models. Tissue and excreta distributions, as well as bioaccumulation and elimination kinetics after administration of racemate and pure enantiomers, have been analyzed in these studies. Changes in enantiomeric fractions have been considered as an indicator of enantioselective biotransformation of chiral POPs in most studies. Results of different laboratory animal models revealed that chiral POP biotransformation is seriously affected by chirality. Pronounced results of species-, tissue-, gender-, and individual-dependent differences are observed in in vivo biotransformation of chiral POPs

Radiative neutrino mass and Majorana dark matter within an inert Higgs doublet model

Science.gov (United States)

Ahriche, Amine; Jueid, Adil; Nasri, Salah

2018-05-01

We consider an extension of the standard model (SM) with an inert Higgs doublet and three Majorana singlet fermions to address both origin and the smallness of neutrino masses and dark matter (DM) problems. In this setup, the lightest Majorana singlet fermion plays the role of DM candidate and the model parameter space can be accommodated to avoid different experimental constraints such as lepton flavor violating processes and electroweak precision tests. The neutrino mass is generated at one-loop level a la Scotogenic model and its smallness is ensured by the degeneracy between the C P -odd and C P -even scalar members of the inert doublet. Interesting signatures at both leptonic and hadronic colliders are discussed.

Symmetries of Ginsparg-Wilson chiral fermions

International Nuclear Information System (INIS)

Mandula, Jeffrey E.

2009-01-01

The group structure of the variant chiral symmetry discovered by Luescher in the Ginsparg-Wilson description of lattice chiral fermions is analyzed. It is shown that the group contains an infinite number of linearly independent symmetry generators, and the Lie algebra is given explicitly. CP is an automorphism of this extended chiral group, and the CP transformation properties of the symmetry generators are found. The group has an infinite-parameter invariant subgroup, and the factor group, whose elements are its cosets, is isomorphic to the continuum chiral symmetry group. Features of the currents associated with these symmetries are discussed, including the fact that some different, noncommuting symmetry generators lead to the same Noether current. These are universal features of lattice chiral fermions based on the Ginsparg-Wilson relation; they occur in the overlap, domain-wall, and perfect-action formulations. In a solvable example, free overlap fermions, these noncanonical elements of lattice chiral symmetry are related to complex energy singularities that violate reflection positivity and impede continuation to Minkowski space.

Chiral ionic liquids in chromatographic and electrophoretic separations.

Science.gov (United States)

Kapnissi-Christodoulou, Constantina P; Stavrou, Ioannis J; Mavroudi, Maria C

2014-10-10

This report provides an overview of the application of chiral ionic liquids (CILs) in separation technology, and particularly in capillary electrophoresis and both gas and liquid chromatography. There is a large number of CILs that have been synthesized and designed as chiral agents. However, only a few have successfully been applied in separation technology. Even though this application of CILs is still in its early stages, the scientific interest is increasing dramatically. This article is focused on the use of CILs as chiral selectors, background electrolyte additives, chiral ligands and chiral stationary phases in electrophoretic and chromatographic techniques. Different examples of CILs, which contain either a chiral cation, a chiral anion or both, are presented in this review article, and their major advantages along with their potential applications in chiral electrophoretic and chromatographic recognition are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Vector mesons and chiral symmetry

International Nuclear Information System (INIS)

Ecker, G.

1989-01-01

The ambiguities in the off-shell behaviour of spin-1 exchange can be resolved to O(p 4 ) in the chiral low-energy expansion if the asymptotic behaviour of QCD is properly incorporated. As a consequence, the chiral version of vector (and axial-vector) meson dominance is model independent. Additional high-energy constraints motivated by QCD determine the V,A resonance couplings uniquely. In particular, QCD in its effective chiral realization sucessfully predicts Γ(ρ→2π). 10 refs. (Author)

Chiral corrections to the Adler-Weisberger sum rule

Science.gov (United States)

Beane, Silas R.; Klco, Natalie

2016-12-01

The Adler-Weisberger sum rule for the nucleon axial-vector charge, gA , offers a unique signature of chiral symmetry and its breaking in QCD. Its derivation relies on both algebraic aspects of chiral symmetry, which guarantee the convergence of the sum rule, and dynamical aspects of chiral symmetry breaking—as exploited using chiral perturbation theory—which allow the rigorous inclusion of explicit chiral symmetry breaking effects due to light-quark masses. The original derivations obtained the sum rule in the chiral limit and, without the benefit of chiral perturbation theory, made various attempts at extrapolating to nonvanishing pion masses. In this paper, the leading, universal, chiral corrections to the chiral-limit sum rule are obtained. Using PDG data, a recent parametrization of the pion-nucleon total cross sections in the resonance region given by the SAID group, as well as recent Roy-Steiner equation determinations of subthreshold amplitudes, threshold parameters, and correlated low-energy constants, the Adler-Weisberger sum rule is confronted with experimental data. With uncertainty estimates associated with the cross-section parametrization, the Goldberger-Treimann discrepancy, and the truncation of the sum rule at O (Mπ4) in the chiral expansion, this work finds gA=1.248 ±0.010 ±0.007 ±0.013 .

Indication for a K/sup π/ = 0- octupole band in 150Nd from electron scattering

International Nuclear Information System (INIS)

Creswell, C.; Hirsch, A.; Bertozzi, W.; Heisenberg, J.; Kowalski, S.; Sargent, C.P.; Turchinetz, W.; Dieperink, A.

1978-01-01

Recent electron scattering results on the 0.850 MeV level of 150 Nd, when analyzed in terms of the interacting boson model, are inconsistent with the interpretation of this level as a pure J/sup π/(K) = 2 + (0) state. Very recent (n,n'γ) work has shown this level to be a 1 - , 2 + doublet. Assuming this level to be the band head of a ''K/sup π/ = 0 - '' octupole band, a simple model is used to predict electron scattering form factors for the 0.850 MeV state and a 3 - octupole level observed at 0.931 MeV. Comparison is made between these predicted form factors and recent electron scattering data

Chiral discrimination in nuclear magnetic resonance spectroscopy

Science.gov (United States)

Lazzeretti, Paolo

2017-11-01

Chirality is a fundamental property of molecules whose spatial symmetry is characterized by the absence of improper rotations, making them not superimposable to their mirror image. Chiral molecules constitute the elementary building blocks of living species and one enantiomer is favoured in general (e.g. L-aminoacids and D-sugars pervade terrestrial homochiral biochemistry) because most chemical reactions producing natural substances are enantioselective. Since the effect of chiral chemicals and drugs on living beings can be markedly different between enantiomers, the quest for practical spectroscopical methods to scrutinize chirality is an issue of great importance and interest. Nuclear magnetic resonance (NMR) is a topmost analytical technique, but spectrometers currently used are ‘blind’ to chirality, i.e. unable to discriminate the two mirror-image forms of a chiral molecule, because, in the absence of a chiral solvent, the spectral parameters, chemical shifts and spin-spin coupling constants are identical for enantiomers. Therefore, the development of new procedures for routine chiral recognition would offer basic support to scientists. However, in the presence of magnetic fields, a distinction between true and false chirality is mandatory. The former epitomizes natural optical activity, which is rationalized by a time-even pseudoscalar, i.e. the trace of a second-rank tensor, the mixed electric dipole/magnetic dipole polarizability. The Faraday effect, magnetic circular dichroism and magnetic optical activity are instead related to a time-odd axial vector. The present review summarizes recent theoretical and experimental efforts to discriminate enantiomers via NMR spectroscopy, with the focus on the deep connection between chirality and symmetry properties under the combined set of fundamental discrete operations, namely charge conjugation, parity (space inversion) and time (motion) reversal.

Algebraic study of chiral anomalies

Indian Academy of Sciences (India)

Chiral anomalies; gauge theories; bundles; connections; quantum field ... The algebraic structure of chiral anomalies is made globally valid on non-trivial bundles by the introduction of a fixed background connection. ... Current Issue : Vol.

Supersymmetric chiral electrodynamics as a renormalized theory

International Nuclear Information System (INIS)

Ansel'm, A.A.; Iogansen, A.A.

1991-01-01

It is well know that the QED of chiral fermions is a nonrenormalizable theory, inasmuch as the gauge current in it is not conserved because of the presence of an anomaly. It is evident that in this theory unitarity is also violated. The principal object of investigation in the present paper is supersymmetric chiral QED, supersymmetric QED is a renormalizable theory. This happens because the radiative corrections generate here a charged current of a chiral fermion that appears in the chiral (i.e., longitudinal) part of the vector supermultiplet. At first sight, the chiral part of the vector multiplet is unphysical and contains only supergauge degrees of freedom. However, this is valid only at the classical level, whereas, because of the anomaly, the radiative corrections lead to nonconservation of the gauge current, as a result of which the degrees of freedom associated with the chiral part of the vector multiplet become physical. On the other hand, owing to the nonconservation of the gauge charge, the apparently neutral fermion appearing int he chiral (longitudinal) part of the vector superfield becomes charged

Chirality plays important roles in radiopharmaceuticals

International Nuclear Information System (INIS)

Shen Yumei

2006-01-01

The paper introduces the basic concept of chirality, target specific selectivity and their relationship in radiopharmaceuticals. If the ligands labeled by radionuclides have chiral center, the enantiomers must be separated, or the target specific selectivity will not be good. Chirality is one of the most important factors which must be considered in the study of the structure-activity relationship of radiopharmaceuticals. (authors)

New viable region of an inert Higgs doublet dark matter model with scotogenic extension

Science.gov (United States)

Borah, Debasish; Gupta, Aritra

2017-12-01

We explore the intermediate dark matter mass regime of the inert Higgs doublet model, approximately between 400 and 550 GeV, which is allowed by latest constraints from direct and indirect detection experiments, but the thermal relic abundance remains suppressed. We extend the model by three copies of right-handed neutrinos, odd under the built-in Z2 symmetry of the model. This discrete Z2 symmetry of the model allows these right-handed neutrinos to couple to the usual lepton doublets through the inert Higgs doublet allowing the possibility of radiative neutrino mass in the scotogenic fashion. Apart from generating nonzero neutrino mass, such an extension can also revive the intermediate dark matter mass regime. The late decay of the lightest right-handed neutrino to dark matter makes it possible for the usual thermally underabundant dark matter in this intermediate mass regime to satisfy the correct relic abundance limit. The revival of this wide intermediate mass range can have relevance not only for direct and indirect search experiments but also for neutrino experiments as the long lifetime of the lightest right-handed neutrino also results in almost vanishing lightest neutrino mass.

Chiral perturbation theory

International Nuclear Information System (INIS)

Ecker, G.

1996-06-01

After a general introduction to the structure of effective field theories, the main ingredients of chiral perturbation theory are reviewed. Applications include the light quark mass ratios and pion-pion scattering to two-loop accuracy. In the pion-nucleon system, the linear σ model is contrasted with chiral perturbation theory. The heavy-nucleon expansion is used to construct the effective pion-nucleon Lagrangian to third order in the low-energy expansion, with applications to nucleon Compton scattering. (author)

Stability of X-band EPR signals from fingernails under vacuum storage.

Science.gov (United States)

Sholom, Sergey; McKeever, Stephen

2017-12-01

EPR signals of different origin have been tested in human finger- and toe-nails with an X-band EPR technique for different conditions of nail storage. Three different signals were identified, namely a singlet at g=2.005, a doublet at g=2.004 with a splitting constant A=1.8 mT, and an anisotropic signal at g1=2.057, g2=2.029 and g3=2.003 (positions of local extrema). All EPR spectra from nails, whether irradiated or mechanically stressed, can be described as a superposition of these three signals. The singlet is responsible for the background signal (BG), is the main component of radiation-induced signals (RIS) for low doses (100 Gy or lower) and also contributes to mechanically-induced signals (MIS). This signal is quite stable under vacuum storage, but can be reduced almost to zero by soaking in water. The behavior of this signal under ambient conditions depends on many factors, such as absorbed dose, air humidity, and ambient illumination intensity at the place of storage. The doublet arises after exposure of nails to high (few hundreds Gy and higher) doses or after mechanical stress of samples. Depending on how this signal was obtained, it may have bulk or surface locations with quite different stability properties. The surface-located doublet (generated on the nail edges during cutting or clipping) is quite unstable and decays over about two hours for samples stored at ambient conditions and within several seconds for samples immersed in water. The volume-distributed doublet decays within a few minutes in water, several hours at ambient conditions and several days in vacuum. The anisotropic signal may also be generated by both ionizing radiation and mechanical stress; this signal is quite stable in vacuum and decays over several days at ambient conditions or a few tens of minutes in water. The reference lines for the above-described three EPR signals were obtained and a procedure of spectra deconvolution was developed and tested on samples exposed to both

Holographic Chiral Magnetic Spiral

International Nuclear Information System (INIS)

Kim, Keun-Young; Sahoo, Bindusar; Yee, Ho-Ung

2010-06-01

We study the ground state of baryonic/axial matter at zero temperature chiral-symmetry broken phase under a large magnetic field, in the framework of holographic QCD by Sakai-Sugimoto. Our study is motivated by a recent proposal of chiral magnetic spiral phase that has been argued to be favored against previously studied phase of homogeneous distribution of axial/baryonic currents in terms of meson super-currents dictated by triangle anomalies in QCD. Our results provide an existence proof of chiral magnetic spiral in strong coupling regime via holography, at least for large axial chemical potentials, whereas we don't find the phenomenon in the case of purely baryonic chemical potential. (author)

Nonclassical Effects of a Four-Level Excited-Doublet Atom Model

International Nuclear Information System (INIS)

Zhang Jiansong; Xu Jingbo

2006-01-01

We adopt a dynamical algebraic method to study a four-level excited-doublet atom model and obtain the explicit expressions of the time-evolution operator and the density operator for the system. The nonclassical effects of the system, such as collapses and revivals of the atomic inversion and squeezing of the radiation field, are also discussed.

Doublet channel neutron-deuteron scattering in leading order effective field theory

OpenAIRE

B. BlankleiderFlinders U.; J. Gegelia(INFN)

2015-01-01

The doublet channel neutron-deuteron scattering amplitude is calculated in leading order effective field theory (EFT). It is shown that this amplitude does not depend on a constant contact interaction three-body force. Satisfactory agreement with available data is obtained when only two-body forces are included.

Synthesis and characterization of mixed ligand chiral nanoclusters

KAUST Repository

Guven, Zekiye P.; Ustbas, Burcin; Harkness, Kellen M.; Coskun, Hikmet; Joshi, Chakra Prasad; Besong, Tabot M.D.; Stellacci, Francesco; Bakr, Osman; Akbulut, Ozge

2016-01-01

Chiral mixed ligand silver nanoclusters were synthesized in the presence of a chiral and an achiral ligand. While the chiral ligand led mostly to the formation of nanoparticles, the presence of the achiral ligand drastically increased the yield of nanoclusters with enhanced chiral properties. © 2016 The Royal Society of Chemistry.

Synthesis and characterization of mixed ligand chiral nanoclusters

KAUST Repository

Guven, Zekiye P.

2016-06-22

Chiral mixed ligand silver nanoclusters were synthesized in the presence of a chiral and an achiral ligand. While the chiral ligand led mostly to the formation of nanoparticles, the presence of the achiral ligand drastically increased the yield of nanoclusters with enhanced chiral properties. © 2016 The Royal Society of Chemistry.

CP properties of symmetry-constrained two-Higgs-doublet models

CERN Document Server

Ferreira, P M; Nachtmann, O; Silva, Joao P

2010-01-01

The two-Higgs-doublet model can be constrained by imposing Higgs-family symmetries and/or generalized CP symmetries. It is known that there are only six independent classes of such symmetry-constrained models. We study the CP properties of all cases in the bilinear formalism. An exact symmetry implies CP conservation. We show that soft breaking of the symmetry can lead to spontaneous CP violation (CPV) in three of the classes.

Illuminating the chirality of Weyl fermions

Science.gov (United States)

Ma, Qiong; Xu, Su-Yang; Chan, Ching-Kit; Zhang, Cheng-Long; Chang, Guoqing; Lin, Hsin; Jia, Shuang; Lee, Patrick; Gedik, Nuh; Jarillo-Herrero, Pablo

In particle physics, Weyl fermions (WF) are elementary particles that travel at the speed of light and have a definite chirality. In condensed matter, it has been recently realized that WFs can arise as magnetic monopoles in the momentum space of a novel topological metal, the Weyl semimetal (WSM). Their chirality, given by the sign of the monopole charge, is the defining property of a WSM, since it directly serves as the topological number and gives rise to exotic properties such as Fermi arcs and the chiral anomaly. Moreover, the two chiralities, analogous to the two valleys in 2D materials, lead to a new degree of freedom in a 3D crystal, suggesting novel pathways to store and carry information. By shining circularly polarized light on the WSM TaAs, we illuminate the chirality of the WFs and achieve an electrical current that is highly controllable based on the WFs' chirality. Our results open up a wide range of new possibilities for experimentally studying and controlling the WFs and their associated quantum anomalies by optical and electrical means, which suggest the exciting prospect of ``Weyltronics''.

Effect of vacancy defect on electrical properties of chiral single-walled carbon nanotube under external electrical field

International Nuclear Information System (INIS)

Luo Yu-Pin; Tien Li-Gan; Tsai Chuen-Horng; Lee Ming-Hsien; Li Feng-Yin

2011-01-01

Ab initio calculations demonstrated that the energy gap modulation of a chiral carbon nanotube with mono-vacancy defect can be achieved by applying a transverse electric field. The bandstructure of this defective carbon nanotube varying due to the external electric field is distinctly different from those of the perfect nanotube and defective zigzag nanotube. This variation in bandstructure strongly depends on not only the chirality of the nanotube and also the applied direction of the transverse electric field. A mechanism is proposed to explain the response of the local energy gap between the valence band maximum state and the local gap state under external electric field. Several potential applications of these phenomena are discussed. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

New chiral zwitterionic phosphorus heterocycles: synthesis, structure, properties and application as chiral solvating agents.

Science.gov (United States)

Sheshenev, Andrey E; Boltukhina, Ekaterina V; Grishina, Anastasiya A; Cisařova, Ivana; Lyapkalo, Ilya M; Hii, King Kuok Mimi

2013-06-17

A family of new chiral zwitterionic phosphorus-containing heterocycles (zPHC) have been derived from methylene-bridged bis(imidazolines). These structures were unambiguously determined, including single-crystal XRD analysis for two compounds. The stability, acid/base and electronic properties of these dipolar phosphorus heterocycles were subsequently investigated. zPHCs can be successfully employed as a new class of chiral solvating agents for the enantiodifferentiation of chiral carboxylic and sulfonic acids by NMR spectroscopy. The stoichiometry and binding constants for the donor-acceptor complexes formed were established by NMR titration methods. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Doublet III limiter performance and implications for mechanical design and material selection for future limiters

International Nuclear Information System (INIS)

Sabado, M.M.; Marcus, F.B.; Trester, P.W.; Wesley, J.C.

1979-10-01

The plasma limiter system for Doublet III is described. Initially, high-Z materials, Ta-10W for the primary limiter and Mo for the backup limiters, were selected as the most attractive metallic candidates from the standpoint of thermal and structural properties. For the purpose of evaluating the effect of material Z on plasma performance, the nonmagnetic, Ni-base alloy Inconel X-750 was selected for a medium-Z limiter material. Graphite, a low-Z material, will likely be the next limiter material for evaluation. Design and material selection criteria for the different Z ranges are presented. The performance of the high-Z limiters in Doublet III is reviewed for an operation period that included approximately 5000 plasma shots. Changes in surface appearance and metallurgical changes are characterized. Discussion is presented on how and to what extent the high-Z elements affected the performance of the plasma based on theory and measurements in Doublet III. The fabrication processes for the Inconel X-750 limiters are summarized, and, last, observations on early performance of the Inconel limiters are described

Doublet III limiter performance and implications for mechanical design and material selection for future limiters

Energy Technology Data Exchange (ETDEWEB)

Sabado, M.M.; Marcus, F.B.; Trester, P.W.; Wesley, J.C.

1979-10-01

The plasma limiter system for Doublet III is described. Initially, high-Z materials, Ta-10W for the primary limiter and Mo for the backup limiters, were selected as the most attractive metallic candidates from the standpoint of thermal and structural properties. For the purpose of evaluating the effect of material Z on plasma performance, the nonmagnetic, Ni-base alloy Inconel X-750 was selected for a medium-Z limiter material. Graphite, a low-Z material, will likely be the next limiter material for evaluation. Design and material selection criteria for the different Z ranges are presented. The performance of the high-Z limiters in Doublet III is reviewed for an operation period that included approximately 5000 plasma shots. Changes in surface appearance and metallurgical changes are characterized. Discussion is presented on how and to what extent the high-Z elements affected the performance of the plasma based on theory and measurements in Doublet III. The fabrication processes for the Inconel X-750 limiters are summarized, and, last, observations on early performance of the Inconel limiters are described. (MOW)

Chiral anomalies and differential geometry

International Nuclear Information System (INIS)

Zumino, B.

1983-10-01

Some properties of chiral anomalies are described from a geometric point of view. Topics include chiral anomalies and differential forms, transformation properties of the anomalies, identification and use of the anomalies, and normalization of the anomalies. 22 references

What's wrong with anomalous chiral gauge theory?

International Nuclear Information System (INIS)

Kieu, T.D.

1994-05-01

It is argued on general ground and demonstrated in the particular example of the Chiral Schwinger Model that there is nothing wrong with apparently anomalous chiral gauge theory. If quantised correctly, there should be no gauge anomaly and chiral gauge theory should be renormalisable and unitary, even in higher dimensions and with non-Abelian gauge groups. Furthermore, it is claimed that mass terms for gauge bosons and chiral fermions can be generated without spoiling the gauge invariance. 19 refs

Self-inductance of chiral conducting nanotubes

International Nuclear Information System (INIS)

Miyamoto, Yoshiyuki; Rubio, Angel; Louie, Steven G.; Cohen, Marvin L.

1998-01-01

Chiral conductivity in nanotubes has recently been predicted theoretically. The realization and application of chiral conducting nanotubes can be of great interest from both fundamental and technological viewpoints. These chiral currents, if they are realized, can be detected by measuring the self-inductance. We have treated Maxwell's equations for chiral conducting nanotubes (nanocoils) and find that the self-inductance and the resistivity of nanocoils should depend on the frequency of the alternating current even when the capacitance of the nanocoils is not taken into account. This is in contrast to elementary treatment of ordinary coils. This fact is useful to distinguish nanocoils by electrical measurements

Macroscopic chirality of a liquid crystal from nonchiral molecules

International Nuclear Information System (INIS)

Jakli, A.; Nair, G. G.; Lee, C. K.; Sun, R.; Chien, L. C.

2001-01-01

The transfer of chirality from nonchiral polymer networks to the racemic B2 phase of nonchiral banana-shaped molecules is demonstrated. This corresponds to the transfer of chirality from an achiral material to another achiral material. There are two levels of chirality transfers. (a) On a microscopic level the presence of a polymer network (chiral or nonchiral) favors a chiral state over a thermodynamically stable racemic state due to the inversion symmetry breaking at the polymer-liquid crystal interfaces. (b) A macroscopically chiral (enantimerically enriched) sample can be produced if the polymer network has a helical structure, and/or contains chemically chiral groups. The chirality transfer can be locally suppressed by exposing the liquid crystal to a strong electric field treatment

Chiral symmetry breaking is permitted in supersymmetric QED

International Nuclear Information System (INIS)

Walker, M.

2000-01-01

Full text: A chirally symmetric theory will generally have a chirally symmetric and a chirally asymmetric solution for the dressed fermionic propagator. It has been claimed that no chirally asymmetric solution for the fermionic propagator exists in supersymmetric QED. This result in the superfield formalism uses a gauge dependent argument whose validity has since been questioned. We present an analogous analysis using the component formalism which demonstrates that chiral symmetry breaking is permitted in this theory. We open the presentation with a brief introduction to supersymmetry, supersymmetric QED, and the superfield formalism. We describe chiral symmetry breaking and the Dyson-Schwinger equation used to analyse it. The derivation of the erroneous theorem claiming the lack of an a chiral propagator is outlined and its flaws discussed. We finish with the equivalent derivation in component fields and our contradictory result

Chiral spiral induced by a strong magnetic field

Directory of Open Access Journals (Sweden)

Abuki Hiroaki

2016-01-01

Full Text Available We study the modification of the chiral phase structure of QCD due to an external magnetic field. We first demonstrate how the effect of magnetic field can systematically be incorporated into a generalized Ginzburg-Landau framework. We then analyze the phase structure in the vicinity of the chiral critical point. In the chiral limit, the effect is found to be so drastic that it brings a “continent” of chiral spiral in the phase diagram, by which the chiral tricritical point is totally washed out. This is the case no matter how small the intensity of magnetic field is. On the other hand, the current quark mass protects the chiral critical point from a weak magnetic field. However, the critical point will eventually be covered by the chiral spiral phase as the magnetic field grows.

Sizable NSI from the SU(2){sub L} scalar doublet-singlet mixing and the implications in DUNE

Energy Technology Data Exchange (ETDEWEB)

Forero, David V. [Center for Neutrino Physics, Virginia Tech,Blacksburg, VA, 24061 (United States); Huang, Wei-Chih [Fakultät für Physik, Technische Universität Dortmund,Dortmund, 44221 (Germany)

2017-03-03

We propose a novel and simple mechanism where sizable effects of non-standard interactions (NSI) in neutrino propagation are induced from the mixing between an electrophilic second Higgs doublet and a charged singlet. The mixing arises from a dimensionful coupling of the scalar doublet and singlet to the standard model Higgs boson. In light of the small mass, the light mass eigenstate from the doublet-singlet mixing can generate much larger NSI than those induced by the heavy eigenstate. We show that a sizable NSI ε{sub eτ} (∼0.3) can be attained without being excluded by a variety of experimental constraints. Furthermore, we demonstrate that NSI can mimic effects of the Dirac CP phase in the neutrino mixing matrix but they can potentially be disentangled by future long-baseline neutrino experiments, such as the Deep Underground Neutrino Experiment (DUNE).

Broken chiral symmetry and the structure of hadrons

International Nuclear Information System (INIS)

Spence, W.L.

1982-01-01

The spontaneous breaking of chiral symmetry plays a decisive role in the structure of hadrons composed of light quarks. The formalism by which the dynamics of chiral symmetry breaking and its implications for hadronic structure can be explored in a simplified world in which fully relativistic zero-bare-mass quarks interact through a chirally symmetric instantaneous confining potential is presented. By thus modeling the essentials of the chiral limit-N/sub c/ infinity limit of QCD contact is made with the successes of existent semiphenomenological models of hadrons but post assumptions which explicitly violate chiral symetry are avoided. This revised approach then makes possible a unification of the dynamics of hadron structure with the mechanism of spontaneous chiral breaking and guarantees the appearance of the correct Goldstone excitations. The chiral breaking order parameter (absolute value anti psi psi), effective quark mass, and Goldstone boson wave function are obtainable by solving a single non-linear integral equation once a potential has been prescribed. The stability of the chiral asymmetric vacuum must then be established by studying the linear eigenvalue problem which determines the spectrum of states with vacuum quantum numbers. The nature of the instability of the chiral symmetric vacuum that leads to spontaneous symmetry breaking is explained and its apparent contingency on details of the dynamics is emphasized. It is argued that a single massless fermion in a chirally symmetric potential does form bound states for which a semi-classical description is given. Coupling to vacuum pairs of such bound states occasions the possibility of chiral symmetry breakdown

Restrictions on two Higgs doublet models and CP violation at the unification scale

International Nuclear Information System (INIS)

Athanasiu, G.G.

1987-04-01

Bounds on charged Higgs masses and couplings in models with two Higgs doublets are examined that came from CP violation in the neutral K system. Bounds on charged Higgs masses and couplings in two Higgs doublet models are also obtained from their effects on neutral-B-meson mixing. The bounds are found to be comparable to those obtained with additional assumptions from the neutral K system. The three generation phase invariant measure of CP violation is shown to satisfy a simple and solvable renormalization group equation. Its value is seen to fall by four to eight orders of magnitude between the weak and grand unification scales in the standard model, as well as in its two Higgs and supersymmetric extensions

Speciation and gene flow between snails of opposite chirality.

Directory of Open Access Journals (Sweden)

Angus Davison

2005-09-01

Full Text Available Left-right asymmetry in snails is intriguing because individuals of opposite chirality are either unable to mate or can only mate with difficulty, so could be reproductively isolated from each other. We have therefore investigated chiral evolution in the Japanese land snail genus Euhadra to understand whether changes in chirality have promoted speciation. In particular, we aimed to understand the effect of the maternal inheritance of chirality on reproductive isolation and gene flow. We found that the mitochondrial DNA phylogeny of Euhadra is consistent with a single, relatively ancient evolution of sinistral species and suggests either recent "single-gene speciation" or gene flow between chiral morphs that are unable to mate. To clarify the conditions under which new chiral morphs might evolve and whether single-gene speciation can occur, we developed a mathematical model that is relevant to any maternal-effect gene. The model shows that reproductive character displacement can promote the evolution of new chiral morphs, tending to counteract the positive frequency-dependent selection that would otherwise drive the more common chiral morph to fixation. This therefore suggests a general mechanism as to how chiral variation arises in snails. In populations that contain both chiral morphs, two different situations are then possible. In the first, gene flow is substantial between morphs even without interchiral mating, because of the maternal inheritance of chirality. In the second, reproductive isolation is possible but unstable, and will also lead to gene flow if intrachiral matings occasionally produce offspring with the opposite chirality. Together, the results imply that speciation by chiral reversal is only meaningful in the context of a complex biogeographical process, and so must usually involve other factors. In order to understand the roles of reproductive character displacement and gene flow in the chiral evolution of Euhadra, it will be

Higher derivative regularization and chiral anomaly

International Nuclear Information System (INIS)

Nagahama, Yoshinori.

1985-02-01

A higher derivative regularization which automatically leads to the consistent chiral anomaly is analyzed in detail. It explicitly breaks all the local gauge symmetry but preserves global chiral symmetry and leads to the chirally symmetric consistent anomaly. This regularization thus clarifies the physics content contained in the consistent anomaly. We also briefly comment on the application of this higher derivative regularization to massless QED. (author)

New remarks on chiral bosonization

International Nuclear Information System (INIS)

Souza Dutra, A. de

1992-01-01

We discuss a certain duality between the constraints appearing in ordinary Lagrangian density and its first order counterpart for the gauged Siegel chiral boson. It is demonstrated the equivalence, at the classical level, of the two versions of the gauged Siegel chiral boson to its corresponding gauged Floreanini-Jackiw chiral bosons. It is also argued that the most general constrained Lagrangian density, that leads to a bosonic field obeying a first order differential equation of motion and preserve simultaneously Lorentz invariance, is just the Floreanini-Jackiw one. (author)

Chiral gravity, log gravity, and extremal CFT

International Nuclear Information System (INIS)

Maloney, Alexander; Song Wei; Strominger, Andrew

2010-01-01

We show that the linearization of all exact solutions of classical chiral gravity around the AdS 3 vacuum have positive energy. Nonchiral and negative-energy solutions of the linearized equations are infrared divergent at second order, and so are removed from the spectrum. In other words, chirality is confined and the equations of motion have linearization instabilities. We prove that the only stationary, axially symmetric solutions of chiral gravity are BTZ black holes, which have positive energy. It is further shown that classical log gravity--the theory with logarithmically relaxed boundary conditions--has finite asymptotic symmetry generators but is not chiral and hence may be dual at the quantum level to a logarithmic conformal field theories (CFT). Moreover we show that log gravity contains chiral gravity within it as a decoupled charge superselection sector. We formally evaluate the Euclidean sum over geometries of chiral gravity and show that it gives precisely the holomorphic extremal CFT partition function. The modular invariance and integrality of the expansion coefficients of this partition function are consistent with the existence of an exact quantum theory of chiral gravity. We argue that the problem of quantizing chiral gravity is the holographic dual of the problem of constructing an extremal CFT, while quantizing log gravity is dual to the problem of constructing a logarithmic extremal CFT.

Confining but chirally symmetric dense and cold matter

International Nuclear Information System (INIS)

Glozman, L. Ya.

2012-01-01

The possibility for existence of cold, dense chirally symmetric matter with confinement is reviewed. The answer to this question crucially depends on the mechanism of mass generation in QCD and interconnection of confinement and chiral symmetry breaking. This question can be clarified from spectroscopy of hadrons and their axial properties. Almost systematical parity doubling of highly excited hadrons suggests that their mass is not related to chiral symmetry breaking in the vacuum and is approximately chirally symmetric. Then there is a possibility for existence of confining but chirally symmetric matter. We clarify a possible mechanism underlying such a phase at low temperatures and large density. Namely, at large density the Pauli blocking prevents the gap equation to generate a solution with broken chiral symmetry. However, the chirally symmetric part of the quark Green function as well as all color non-singlet quantities are still infrared divergent, meaning that the system is with confinement. A possible phase transition to such a matter is most probably of the first order. This is because there are no chiral partners to the lowest lying hadrons.

Close near-degeneracy in a pair of four-quasiparticle bands in 194Tl

International Nuclear Information System (INIS)

Masiteng, P.L.; Lawrie, E.A.; Ramashidzha, T.M.; Bark, R.A.; Carlsson, B.G.; Lawrie, J.J.; Lindsay, R.; Komati, F.; Kau, J.; Maine, P.; Maliage, S.M.; Matamba, I.; Mullins, S.M.; Murray, S.H.T.; Mutshena, K.P.; Pasternak, A.A.; Ragnarsson, I.

2013-01-01

A pair of rotational bands associated with the πh 9/2 ⊗νi 13/2 −1 configuration at lower spins and with the πh 9/2 ⊗νi 13/2 −3 configuration at higher spins is found in 194 Tl. The two 4-quasiparticle bands show exceptionally close near-degeneracy in the excitation energies. Furthermore close similarity is also found in their alignments and B(M1)/B(E2) reduced transition probability ratios. Such close near-degeneracy probably indicates chiral geometry in the angular momentum space

Energy confinement in Doublet III with high-Z limiters

Energy Technology Data Exchange (ETDEWEB)

Marcus, F.B.; Adcock, S.J.; Baker, D.R.; Blau, F.P.; Brooks, N.H.; Chase, R.P.; DeBoo, J.C.; Ejima, S.; Fairbanks, E.S.; Fisher, R.K.

1980-02-01

This report describes the experimental measurements and data analysis techniques used to evaluate the energy confinement in noncircular plasmas produced in Doublet III. Major aspects of the confinement measurements and analysis techniques are summarized. Machine parameters, diagnostic systems and discharge parameters relavent to the confinement measurements are given. Magnetic analysis techniques used to determine the plasma shape are reviewed. Scaling of the on-axis values of electron temperature, confinement time and Z/sub eff/ with plasma density is presented. Comparison with scaling results from other circular tokamaks is discussed. Numerical and analytic techniques developed for calculating the plasma energy confinement time and self-consistent profiles of density, temperature, current, and flux in non-circular geometries are described. These techniques are applied to the data and used to determine the central and global electron energy confinement time for a typical doublet plasma. Additional aspects of the confinement such as the radial dependence of the electron thermal conductivity and the estimated ion temperature are explored with the aid of a non-circular transport simulation code. The results of the confinement measurements are summarized and discussed. A brief summary of the theoretically expected effects of noncircularity on plasma confinement is included for reference as Appendix I.

Doublet III neutral beam injector test tank cryopanel design

International Nuclear Information System (INIS)

Doll, D.W.; Kamperschroer, J.H.; Arend, P.V.

1980-03-01

A simple condensing cryopanel has been designed for the Doublet III neutral beam test tank with a 320,000 liters per second pumping capacity for hydrogen. This maintains a vacuum in the test tank which simulates the Doublet III vessel, 1.3 x 10 -3 Pa (approx.10 -5 torr). The hydrogen gas load comes from the beam striking the test tank calorimeter and amounts to about 7.2 torr liters per second. The cryopanel is cylindrical shaped with a liquid helium (LHe) surface that pumps through liquid nitrogen (LN) cooled aluminum chevrons located in squirrel-cage fashion around the inside surface of the cylinder. The LHe cooled surface is a smooth cylinder 2.09m in diameter by .69m long with LHe flowing in a approx. 1mm annular space between concentric cylinders. The chevrons which are not blackened are cooled from each end with LN flowing in ring manifolds that serve as the primary cryopanel structure. The LHe is force fed at 55.2 kPa remaining in the liquid phase through the panel. External heat exchanger capability permits use of helium at 3.8 to 4.2 0 K. Normal operating flow rate is 1.4 g/sec for a heat load expected to be 12.2 W total

Chirality-Controlled Synthesis and Applications of Single-Wall Carbon Nanotubes.

Science.gov (United States)

Liu, Bilu; Wu, Fanqi; Gui, Hui; Zheng, Ming; Zhou, Chongwu

2017-01-24

Preparation of chirality-defined single-wall carbon nanotubes (SWCNTs) is the top challenge in the nanotube field. In recent years, great progress has been made toward preparing single-chirality SWCNTs through both direct controlled synthesis and postsynthesis separation approaches. Accordingly, the uses of single-chirality-dominated SWCNTs for various applications have emerged as a new front in nanotube research. In this Review, we review recent progress made in the chirality-controlled synthesis of SWCNTs, including metal-catalyst-free SWCNT cloning by vapor-phase epitaxy elongation of purified single-chirality nanotube seeds, chirality-specific growth of SWCNTs on bimetallic solid alloy catalysts, chirality-controlled synthesis of SWCNTs using bottom-up synthetic strategy from carbonaceous molecular end-cap precursors, etc. Recent major progresses in postsynthesis separation of single-chirality SWCNT species, as well as methods for chirality characterization of SWCNTs, are also highlighted. Moreover, we discuss some examples where single-chirality SWCNTs have shown clear advantages over SWCNTs with broad chirality distributions. We hope this review could inspire more research on the chirality-controlled preparation of SWCNTs and equally important inspire the use of single-chirality SWCNT samples for more fundamental studies and practical applications.

Chirality detection of enantiomers using twisted optical metamaterials

Science.gov (United States)

Zhao, Yang; Askarpour, Amir N.; Sun, Liuyang; Shi, Jinwei; Li, Xiaoqin; Alù, Andrea

2017-01-01

Many naturally occurring biomolecules, such as amino acids, sugars and nucleotides, are inherently chiral. Enantiomers, a pair of chiral isomers with opposite handedness, often exhibit similar physical and chemical properties due to their identical functional groups and composition, yet show different toxicity to cells. Detecting enantiomers in small quantities has an essential role in drug development to eliminate their unwanted side effects. Here we exploit strong chiral interactions with plasmonic metamaterials with specifically designed optical response to sense chiral molecules down to zeptomole levels, several orders of magnitude smaller than what is typically detectable with conventional circular dichroism spectroscopy. In particular, the measured spectra reveal opposite signs in the spectral regime directly associated with different chiral responses, providing a way to univocally assess molecular chirality. Our work introduces an ultrathin, planarized nanophotonic interface to sense chiral molecules with inherently weak circular dichroism at visible and near-infrared frequencies. PMID:28120825

Nucleon parton distributions in chiral perturbation theory

International Nuclear Information System (INIS)

Moiseeva, Alena

2013-01-01

Properties of the chiral expansion of nucleon light-cone operators have been studied. In the framework of the chiral perturbation theory we have demonstrated that convergency of the chiral expansion of nucleon parton distributions strongly depends on the value of the variable x. Three regions in x with essentially different analytical properties of the resulting chiral expansion for parton distributions were found. For each of the regions we have elaborated special power counting rules corresponding to the partial resummation of the chiral series. The nonlocal effective operators for the vector and the axial nucleon parton distributions have been constructed at the zeroth and the first chiral order. Using the derived nonlocal operators and the derived power counting rules we have obtained the second order expressions for the nucleon GPDs H(x,ξ,Δ 2 ), H(x,ξ,Δ 2 ),E(x,ξ,Δ 2 ) valid in the region x>or similar a 2 χ .

Cosmic chirality both true and false.

Science.gov (United States)

Barron, Laurence D

2012-12-01

The discrete symmetries of parity P, time reversal T, and charge conjugation C may be used to characterize the properties of chiral systems. It is well known that parity violation infiltrates into ordinary matter via an interaction between the nucleons and electrons, mediated by the Z(0) particle, that lifts the degeneracy of the mirror-image enantiomers of a chiral molecule. Being odd under P but even under T, this P-violating interaction exhibits true chirality and so may induce absolute enantioselection under all circumstances. It has been suggested that CP violation may also infiltrate into ordinary matter via a P-odd, T-odd interaction mediated by the (as yet undetected) axion. This CP-violating interaction exhibits false chirality and so may induce absolute enantioselection in processes far from equilibrium. Both true and false cosmic chirality should be considered together as possible sources of homochirality in the molecules of life. Copyright © 2012 Wiley Periodicals, Inc.

Wideband giant optical activity and negligible circular dichroism of near-infrared chiral metamaterial based on a complementary twisted configuration

International Nuclear Information System (INIS)

Zhu, Weiren; Rukhlenko, Ivan D; Premaratne, Malin; Huang, Yongjun; Wen, Guangjun

2013-01-01

We theoretically analyze the near-infrared properties of a chiral metamaterial constituting an array of twisted crosses and complementary crosses made of silver. Through rigorous full-wave numerical simulations, we demonstrate that this type of metamaterial exhibits wideband giant optical activity, with a polarization azimuth rotation angle reaching values as large as 1900 ∘ per wavelength. Owing to the negligible loss at optical frequencies in the dielectric (magnesium fluoride) making up the metamaterial, we observe negligible circular dichroism and low dispersion of the polarization azimuth rotation angle over a wide frequency band. We envision that this type of chiral metamaterial will find extensive applications in optical communication systems and biological sensing. (paper)

Chiral fermions on the lattice

International Nuclear Information System (INIS)

Randjbar Daemi, S.; Strathdee, J.

1995-01-01

The overlap approach to chiral gauge theories on arbitrary D-dimensional lattices is studied. The doubling problem and its relation to chiral anomalies for D = 2 and 4 is examined. In each case it is shown that the doublers can be eliminated and the well known perturbative results for chiral anomalies can be recovered. We also consider the multi-flavour case and give the general criteria for the construction of anomaly free chiral gauge theories on arbitrary lattices. We calculate the second order terms in a continuum approximation to the overlap formula in D dimensions and show that they coincide with the bilinear part of the effective action of D-dimensional Weyl fermions coupled to a background gauge field. Finally, using the same formalism we reproduce the correct Lorentz, diffeomorphism and gauge anomalies in the coupling of a Weyl fermion to 2-dimensional gravitation and Maxwell fields. (author). 15 refs

Quenched Chiral Perturbation Theory to one loop

NARCIS (Netherlands)

Colangelo, G.; Pallante, E.

The divergences of the generating functional of quenched Chiral Perturbation theory (qCHPT) to one loop are computed in closed form. We show how the quenched chiral logarithms can be reabsorbed in the renormalization of the B0 parameter of the leading order Lagrangian. Finally, we do the chiral

Chiral dynamics with (non)strange quarks

International Nuclear Information System (INIS)

Kubis, Bastian; Meißner, Ulf-G.

2017-01-01

We review the results and achievements of the project B.3. Topics addressed include pion photoproduction off the proton and off deuterium, three-flavor chiral perturbation theory studies, chiral symmetry tests in Goldstone boson decays, the development of unitarized chiral perturbation theory to next-to-leading order, the two-pole structure of the Λ(1405), the dynamical generation of the lowest S_1_1 resonances, the theory of hadronic atoms and its application to various systems, precision studies in light-meson decays based on dispersion theory, the Roy–Steiner analysis of pion–nucleon scattering, a high-precision extraction of the elusive pion–nucleon σ-term, and aspects of chiral dynamics in few-nucleon systems.

Chiral dynamics with (non)strange quarks

Science.gov (United States)

Kubis, Bastian; Meißner, Ulf-G.

2017-01-01

We review the results and achievements of the project B.3. Topics addressed include pion photoproduction off the proton and off deuterium, three-flavor chiral perturbation theory studies, chiral symmetry tests in Goldstone boson decays, the development of unitarized chiral perturbation theory to next-to-leading order, the two-pole structure of the Λ(1405), the dynamical generation of the lowest S11 resonances, the theory of hadronic atoms and its application to various systems, precision studies in light-meson decays based on dispersion theory, the Roy-Steiner analysis of pion-nucleon scattering, a high-precision extraction of the elusive pion-nucleon σ-term, and aspects of chiral dynamics in few-nucleon systems.

Deracemization of Racemic Amino Acids Using (R)- and (S)-Alanine Racemase Chiral Analogues as Chiral Converters

International Nuclear Information System (INIS)

Paik, Manjeong; Jeon, So Hee; Lee, Wonjae; Kang, Jong Seong; Kim, Kwan Mook

2014-01-01

Our findings show that both (R)- and (S)-ARCA can be practical chiral converters for L- and D-amino acids, respectively, in the deracemization of racemic amino acids. The overall stereoselectivities of both chiral converters are generally greater than 90%. In addition, we developed chiral and achiral HPLC methods for the analysis of stereoselectivity determination. This chromatographic method proved much more accurate and convenient at determining both enantiomer and diastereomer purity than did those previously reported. Deracemization is the stereoselective process of converting a racemate into either a pure enantiomer or a mixture in which one enantiomer is present in excess.1 Previous studies have shown that (S)-alanine racemase chiral analogue (ARCA) [(S)-2-hydroxy-2'-(3-phenyluryl-benzyl)-1,1'-binaphthyl-3-carboxaldehyde], developed as a chiral convertor compound that imitates the function of alanine racemase, plays an essential role in the stereoselective conversion of amino acid. Since (S)-ARCA showed a higher stability with D-amino acids than with L-amino acids, several L-amino acids were preferentially converted to D-amino acids via (S)-ARCA/D-amino acid imine diastereomer formation. For the deracemization process undertaken in this study, we utilized both (R)-ARCA and (S)-ARCA as chiral converters, which were expected to generate L- and D-amino acids, respectively, from the starting racemic mixtures

Extending two Higgs doublet models for two-loop neutrino mass generation and one-loop neutrinoless double beta decay

Directory of Open Access Journals (Sweden)

Zhen Liu

2017-02-01

Full Text Available We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.

Extending two Higgs doublet models for two-loop neutrino mass generation and one-loop neutrinoless double beta decay

Energy Technology Data Exchange (ETDEWEB)

Liu, Zhen, E-mail: liu-zhen@sjtu.edu.cn; Gu, Pei-Hong, E-mail: peihong.gu@sjtu.edu.cn

2017-02-15

We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.

Chiral symmetry breaking and cooling in lattice QCD

International Nuclear Information System (INIS)

Woloshyn, R.M.; Lee, F.X.

1995-08-01

Chiral symmetry breaking is calculated as a function of cooling in quenched lattice QCD. A non-zero signal is found for the chiral condensate beyond one hundred cooling steps, suggesting that there is chiral symmetry breaking associated with instantons. Quantitatively, the chiral condensate in cooled gauge field configurations is small compared to the value without cooling. (author) 7 refs., 1 tab., 3 figs

A web site for calculating the degree of chirality.

Science.gov (United States)

Zayit, Amir; Pinsky, Mark; Elgavi, Hadassah; Dryzun, Chaim; Avnir, David

2011-01-01

The web site, http://www.csm.huji.ac.il/, uses the Continuous Chirality Measure to evaluate quantitatively the degree of chirality of a molecule, a structure, a fragment. The value of this measure ranges from zero, the molecule is achiral, to higher values (the upper limit is 100); the higher the chirality value, the more chiral the molecule is. The measure is based on the distance between the chiral molecule and the nearest structure that is achiral. Questions such as the following can be addressed: by how much is one molecule more chiral than the other? how does chirality change along conformational motions? is there a correlation between chirality and enantioselectivity in a series of molecules? Both elementary and advanced features are offered. Related calculation options are the symmetry measures and shape measures. Copyright © 2009 Wiley-Liss, Inc.

Two-color QCD with non-zero chiral chemical potential

Energy Technology Data Exchange (ETDEWEB)

Braguta, V.V. [Institute for High Energy Physics NRC “Kurchatov Institute' ,142281 Protvino (Russian Federation); Far Eastern Federal University, School of Biomedicine,690950 Vladivostok (Russian Federation); Goy, V.A. [Far Eastern Federal University, School of Natural Sciences,690950 Vladivostok (Russian Federation); Ilgenfritz, E.M. [Joint Institute for Nuclear Research,BLTP, 141980 Dubna (Russian Federation); Kotov, A.Yu. [Institute of Theoretical and Experimental Physics,117259 Moscow (Russian Federation); Molochkov, A.V. [Far Eastern Federal University, School of Biomedicine,690950 Vladivostok (Russian Federation); Müller-Preussker, M.; Petersson, B. [Humboldt-Universität zu Berlin, Institut für Physik,12489 Berlin (Germany)

2015-06-16

The phase diagram of two-color QCD with non-zero chiral chemical potential is studied by means of lattice simulation. We focus on the influence of a chiral chemical potential on the confinement/deconfinement phase transition and the breaking/restoration of chiral symmetry. The simulation is carried out with dynamical staggered fermions without rooting. The dependences of the Polyakov loop, the chiral condensate and the corresponding susceptibilities on the chiral chemical potential and the temperature are presented. The critical temperature is observed to increase with increasing chiral chemical potential.

Precise predictions within the two-Higgs-doublet model

International Nuclear Information System (INIS)

Altenkamp, Lukas

2017-01-01

We consider the Two-Higgs-Doublet Model (THDM) where the Standard Model (SM) field content is extended by adding a further Higgs-boson doublet. This results in five Higgs bosons, two CP-even, one CP-odd and a charged Higgs boson and it's anti-particle. In order to provide accurate and reliable predictions within this model, next-to-leading order calculations are necessary. To this end, we perform a renormalization procedure and adopt four new renormalization schemes. The counterterm Feynman rules as well as the renormalization conditions are implemented into an FeynArts model file, yielding the possibility to generate amplitudes and squared matrix elements for arbitrary processes which is a major contribution to the automation of higher-order calculations. As an application we investigate the decay of a light, CP-even, SM-like Higgs boson into four fermions in the THDM. To this end, we extend the program Prophecy4f and compute the partial decay widths for different benchmark scenarios. For all investigated scenarios, we observe that the THDM widths are bounded by the SM widths and that the deviations are larger at higher order. The renormalization group equations have been solved in order to investigate the renormalization scale dependence which gives an estimate of the theoretical uncertainty arising due to the truncation of the perturbation series. By comparing the results of different renormalization schemes we determine for which parameter regions each scheme provides reliable predictions.

Precise predictions within the two-Higgs-doublet model

Energy Technology Data Exchange (ETDEWEB)

Altenkamp, Lukas

2017-02-21

We consider the Two-Higgs-Doublet Model (THDM) where the Standard Model (SM) field content is extended by adding a further Higgs-boson doublet. This results in five Higgs bosons, two CP-even, one CP-odd and a charged Higgs boson and it's anti-particle. In order to provide accurate and reliable predictions within this model, next-to-leading order calculations are necessary. To this end, we perform a renormalization procedure and adopt four new renormalization schemes. The counterterm Feynman rules as well as the renormalization conditions are implemented into an FeynArts model file, yielding the possibility to generate amplitudes and squared matrix elements for arbitrary processes which is a major contribution to the automation of higher-order calculations. As an application we investigate the decay of a light, CP-even, SM-like Higgs boson into four fermions in the THDM. To this end, we extend the program Prophecy4f and compute the partial decay widths for different benchmark scenarios. For all investigated scenarios, we observe that the THDM widths are bounded by the SM widths and that the deviations are larger at higher order. The renormalization group equations have been solved in order to investigate the renormalization scale dependence which gives an estimate of the theoretical uncertainty arising due to the truncation of the perturbation series. By comparing the results of different renormalization schemes we determine for which parameter regions each scheme provides reliable predictions.

A variational approach to chiral quark models

International Nuclear Information System (INIS)

Futami, Yasuhiko; Odajima, Yasuhiko; Suzuki, Akira.

1987-01-01

A variational approach is applied to a chiral quark model to test the validity of the perturbative treatment of the pion-quark interaction based on the chiral symmetry principle. It is indispensably related to the chiral symmetry breaking radius if the pion-quark interaction can be regarded as a perturbation. (author)

Synergistic effects on enantioselectivity of zwitterionic chiral stationary phases for separations of chiral acids, bases, and amino acids by HPLC.

Science.gov (United States)

Hoffmann, Christian V; Pell, Reinhard; Lämmerhofer, Michael; Lindner, Wolfgang

2008-11-15

In an attempt to overcome the limited applicability scope of earlier proposed Cinchona alkaloid-based chiral weak anion exchangers (WAX) and recently reported aminosulfonic acid-based chiral strong cation exchangers (SCX), which are conceptionally restricted to oppositely charged solutes, their individual chiral selector (SO) subunits have been fused in a combinatorial synthesis approach into single, now zwitterionic, chiral SO motifs. The corresponding zwitterionic ion-exchange-type chiral stationary phases (CSPs) in fact combined the applicability spectra of the parent chiral ion exchangers allowing for enantioseparations of chiral acids and amine-type solutes in liquid chromatography using polar organic mode with largely rivaling separation factors as compared to the parent WAX and SCX CSPs. Furthermore, the application spectrum could be remarkably expanded to various zwitterionic analytes such as alpha- and beta-amino acids and peptides. A set of structurally related yet different CSPs consisting of either a quinine or quinidine alkaloid moiety as anion-exchange subunit and various chiral or achiral amino acids as cation-exchange subunits enabled us to derive structure-enantioselectivity relationships, which clearly provided strong unequivocal evidence for synergistic effects of the two oppositely charged ion-exchange subunits being involved in molecular recognition of zwitterionic analytes by zwitterionic SOs driven by double ionic coordination.

Transfer of chirality from adsorbed chiral molecules to the substrates highlighted by circular dichroism in angle-resolved valence photoelectron spectroscopy

DEFF Research Database (Denmark)

Contini, G.; Turchini, S.; Sanna, Simone

2012-01-01

Studies of self-assembled chiral molecules on achiral metallic surfaces have mostly focused on the determination of the geometry of adsorbates and their electronic structure. The aim of this paper is to provide direct information on the chirality character of the system and on the chirality...... transfer from molecules to substrate by means of circular dichroism in the angular distribution of valence photoelectrons for the extended domain of the chiral self-assembled molecular structure, formed by alaninol adsorbed on Cu(100). We show, by the dichroic behavior of a mixed molecule–copper valence...... state, that the presence of molecular chiral domains induces asymmetry in the interaction with the substrate and locally transfers the chiral character to the underlying metal atoms participating in the adsorption process; combined information related to the asymmetry of the initial electronic state...

Multiaxial Polarity Determines Individual Cellular and Nuclear Chirality.

Science.gov (United States)

Raymond, Michael J; Ray, Poulomi; Kaur, Gurleen; Fredericks, Michael; Singh, Ajay V; Wan, Leo Q

2017-02-01

Intrinsic cell chirality has been implicated in the left-right (LR) asymmetry of embryonic development. Impaired cell chirality could lead to severe birth defects in laterality. Previously, we detected cell chirality with an in vitro micropatterning system. Here, we demonstrate for the first time that chirality can be quantified as the coordination of multiaxial polarization of individual cells and nuclei. Using an object labeling, connected component based method, we characterized cell chirality based on cell and nuclear shape polarization and nuclear positioning of each cell in multicellular patterns of epithelial cells. We found that the cells adopted a LR bias the boundaries by positioning the sharp end towards the leading edge and leaving the nucleus at the rear. This behavior is consistent with the directional migration observed previously on the boundary of micropatterns. Although the nucleus is chirally aligned, it is not strongly biased towards or away from the boundary. As the result of the rear positioning of nuclei, the nuclear positioning has an opposite chirality to that of cell alignment. Overall, our results have revealed deep insights of chiral morphogenesis as the coordination of multiaxial polarization at the cellular and subcellular levels.

Chiral anomaly, bosonization, and fractional charge

International Nuclear Information System (INIS)

Mignaco, J.A.; Monteiro, M.A.R.

1985-01-01

We present a method to evaluate the Jacobian of chiral rotations, regulating determinants through the proper-time method and using Seeley's asymptotic expansion. With this method we compute easily the chiral anomaly for ν = 4,6 dimensions, discuss bosonization of some massless two-dimensional models, and handle the problem of charge fractionization. In addition, we comment on the general validity of Fujikawa's approach to regulate the Jacobian of chiral rotations with non-Hermitian operators

Chiral properties of baryon interpolating fields

International Nuclear Information System (INIS)

Nagata, Keitaro; Hosaka, Atsushi; Dmitrasinovic, V.

2008-01-01

We study the chiral transformation properties of all possible local (non-derivative) interpolating field operators for baryons consisting of three quarks with two flavors, assuming good isospin symmetry. We derive and use the relations/identities among the baryon operators with identical quantum numbers that follow from the combined color, Dirac and isospin Fierz transformations. These relations reduce the number of independent baryon operators with any given spin and isospin. The Fierz identities also effectively restrict the allowed baryon chiral multiplets. It turns out that the non-derivative baryons' chiral multiplets have the same dimensionality as their Lorentz representations. For the two independent nucleon operators the only permissible chiral multiplet is the fundamental one, ((1)/(2),0)+(0,(1)/(2)). For the Δ, admissible Lorentz representations are (1,(1)/(2))+((1)/(2),1) and ((3)/(2),0)+(0,(3)/(2)). In the case of the (1,(1)/(2))+((1)/(2),1) chiral multiplet, the I(J)=(3)/(2)((3)/(2)) Δ field has one I(J)=(1)/(2)((3)/(2)) chiral partner; otherwise it has none. We also consider the Abelian (U A (1)) chiral transformation properties of the fields and show that each baryon comes in two varieties: (1) with Abelian axial charge +3; and (2) with Abelian axial charge -1. In case of the nucleon these are the two Ioffe fields; in case of the Δ, the (1,(1)/(2))+((1)/(2),1) multiplet has an Abelian axial charge -1 and the ((3)/(2),0)+(0,(3)/(2)) multiplet has an Abelian axial charge +3. (orig.)

Generalized chiral membrane dynamics

International Nuclear Information System (INIS)

Cordero, R.; Rojas, E.

2003-01-01

We develop the dynamics of the chiral superconducting membranes (with null current) in an alternative geometrical approach. Besides of this, we show the equivalence of the resulting description with the one known Dirac-Nambu-Goto (DNG) case. Integrability for chiral string model is obtained using a proposed light-cone gauge. In a similar way, domain walls are integrated by means of a simple Ansatz. (Author)

The ''closed'' chiral symmetry and its application to tetraquark

International Nuclear Information System (INIS)

Chen, Hua-Xing

2012-01-01

We investigate the chiral (flavor) structure of tetraquarks, and study chiral transformation properties of the ''non-exotic'' [(anti 3, 3)+(3, anti 3)] and [(8,1)+(1,8)] tetraquark chiral multiplets. We find that as long as this kind of tetraquark states contains one quark and one antiquark having the same chirality, such as q L q L anti q L anti q R + q R q R anti q R anti q L , they transform in the same way as the lowest level anti q q chiral multiplets under chiral transformations. There is only one [(anti 3, 3)+(3, anti 3)] chiral multiplet whose quark-antiquark pairs all have the opposite chirality (q L q L anti q R anti q R + q R q R anti q L anti q L ), and it transforms differently from others. Based on these studies, we construct local tetraquark currents belonging to the ''non-exotic'' chiral multiplet [(anti 3, 3)+(3, anti 3)] and having quantum numbers J PC =1 -+ . (orig.)

Investigations on a Q0 Doublet Optics for the LHC Luminosity Upgrade

CERN Document Server

Laface, E; Scandale, Walter; Wildner, E

2008-01-01

The Q0 scheme of the LHC insertion region is based on the introduction of a doublet of quadrupoles at 13 m from the IP. We present here the doublet optics and the magnets layout such as gradients, lengths, positions and apertures. In this scheme we show the gain in luminosity and chromaticity, with respect to a nominal layout with $\\beta^{*}$ = 0.25 m (i.e. LHC phase 1 upgrade) and $\\beta^{*} = 0.15 m, due to a smaller beta-max. We show the alignment tolerance and the energy deposition issues, in Q0A-Q0B. We also consider shielding the magnets with liners. The capability of Q0 optics to limit the b function could be exploited after the LHC Phase 1 upgrade in order to reduce the $\\beta^{*}$ below 0.25 m, leaving the upgraded triplet unchanged

A rotated transmission grating spectrometer for detecting spectral separation of doublet Na

Energy Technology Data Exchange (ETDEWEB)

Santosa, Ignatius Edi [Department of Physics Education, Sanata Dharma University, Paingan Maguwohardjo Depok Sleman, Yogyakarta 55281, Indonesia edi@usd.ac.id (Indonesia)

2015-04-16

Transmission gratings are usually used in a spectrometer for measuring the wavelength of light. In the common design, the position of the grating is perpendicular to the incident light. In order to increase the angular dispersion, in contrary to the common design, in this experiment the transmission grating was rotated. Due to the non-zero incident angle, the diffracted light was shifted. This rotated transmission grating spectrometer has been used to determine the separation of doublet Na. In this experiment, the diffraction angle was measured at various incident angles. The spectral separation of doublet Na was identified from the difference in the diffraction angle of two spectral lines. This spectral separation depends on the incident angle, the grating constant and the order of diffraction. As the effect of increasing the incident angle, a significant increase of the spectral separation can be achieved up to three fold.

A rotated transmission grating spectrometer for detecting spectral separation of doublet Na

International Nuclear Information System (INIS)

Santosa, Ignatius Edi

2015-01-01

Transmission gratings are usually used in a spectrometer for measuring the wavelength of light. In the common design, the position of the grating is perpendicular to the incident light. In order to increase the angular dispersion, in contrary to the common design, in this experiment the transmission grating was rotated. Due to the non-zero incident angle, the diffracted light was shifted. This rotated transmission grating spectrometer has been used to determine the separation of doublet Na. In this experiment, the diffraction angle was measured at various incident angles. The spectral separation of doublet Na was identified from the difference in the diffraction angle of two spectral lines. This spectral separation depends on the incident angle, the grating constant and the order of diffraction. As the effect of increasing the incident angle, a significant increase of the spectral separation can be achieved up to three fold

Hierarchical chirality transfer in the growth of Towel Gourd tendrils

Science.gov (United States)

Wang, Jian-Shan; Wang, Gang; Feng, Xi-Qiao; Kitamura, Takayuki; Kang, Yi-Lan; Yu, Shou-Wen; Qin, Qing-Hua

2013-01-01

Chirality plays a significant role in the physical properties and biological functions of many biological materials, e.g., climbing tendrils and twisted leaves, which exhibit chiral growth. However, the mechanisms underlying the chiral growth of biological materials remain unclear. In this paper, we investigate how the Towel Gourd tendrils achieve their chiral growth. Our experiments reveal that the tendrils have a hierarchy of chirality, which transfers from the lower levels to the higher. The change in the helical angle of cellulose fibrils at the subcellular level induces an intrinsic torsion of tendrils, leading to the formation of the helical morphology of tendril filaments. A chirality transfer model is presented to elucidate the chiral growth of tendrils. This present study may help understand various chiral phenomena observed in biological materials. It also suggests that chirality transfer can be utilized in the development of hierarchically chiral materials having unique properties. PMID:24173107

Structure of potentials with N Higgs doublets

International Nuclear Information System (INIS)

Nishi, C. C.

2007-01-01

Extensions of the standard model with N Higgs doublets are simple extensions presenting a rich mathematical structure. An underlying Minkowski structure emerges from the study of both variable space and parameter space. The former can be completely parametrized in terms of two future lightlike Minkowski vectors with spatial parts forming an angle whose cosine is -(N-1) -1 . For the parameter space, the Minkowski parametrization enables one to impose sufficient conditions for bounded below potentials, characterize certain classes of local minima, and distinguish charge breaking vacua from neutral vacua. A particular class of neutral minima presents a degenerate mass spectrum for the physical charged Higgs bosons

Topological magnon bands and unconventional thermal Hall effect on the frustrated honeycomb and bilayer triangular lattice.

Science.gov (United States)

Owerre, S A

2017-09-27

In the conventional ferromagnetic systems, topological magnon bands and thermal Hall effect are due to the Dzyaloshinskii-Moriya interaction (DMI). In principle, however, the DMI is either negligible or it is not allowed by symmetry in some quantum magnets. Therefore, we expect that topological magnon features will not be present in those systems. In addition, quantum magnets on the triangular-lattice are not expected to possess topological features as the DMI or spin-chirality cancels out due to equal and opposite contributions from adjacent triangles. Here, however, we predict that the isomorphic frustrated honeycomb-lattice and bilayer triangular-lattice antiferromagnetic system will exhibit topological magnon bands and topological thermal Hall effect in the absence of an intrinsic DMI. These unconventional topological magnon features are present as a result of magnetic-field-induced non-coplanar spin configurations with nonzero scalar spin chirality. The relevance of the results to realistic bilayer triangular antiferromagnetic materials are discussed.

Maximum entropy technique in the doublet structure analysis

International Nuclear Information System (INIS)

Belashev, B.Z.; Panebrattsev, Yu.A.; Shakhaliev, Eh.I.; Soroko, L.M.

1998-01-01

The Maximum Entropy Technique (MENT) for solution of the inverse problems is explained. The effective computer program for resolution of the nonlinear equations system encountered in the MENT has been developed and tested. The possibilities of the MENT have been demonstrated on the example of the MENT in the doublet structure analysis of noisy experimental data. The comparison of the MENT results with results of the Fourier algorithm technique without regularization is presented. The tolerant noise level is equal to 30% for MENT and only 0.1% for the Fourier algorithm

Vector boson fusion in the inert doublet model

Science.gov (United States)

Dutta, Bhaskar; Palacio, Guillermo; Restrepo, Diego; Ruiz-Álvarez, José D.

2018-03-01

In this paper we probe the inert Higgs doublet model at the LHC using vector boson fusion (VBF) search strategy. We optimize the selection cuts and investigate the parameter space of the model and we show that the VBF search has a better reach when compared with the monojet searches. We also investigate the Drell-Yan type cuts and show that they can be important for smaller charged Higgs masses. We determine the 3 σ reach for the parameter space using these optimized cuts for a luminosity of 3000 fb-1 .

Emulsion sheet doublets as interface trackers for the OPERA experiment

International Nuclear Information System (INIS)

Anokhina, A; Aoki, S; Ariga, A; Arrabito, L; Autiero, D; Brugiere, T; Chaussard, L; Badertscher, A; Bay, F; Greggio, F Bersani; Bertolin, A; Besnier, M; Bick, D; Bozza, C; Brugnera, R; Carrara, E; Brunetti, G; Buontempo, S; Cazes, A; Chernyavsky, M

2008-01-01

New methods for efficient and unambiguous interconnection between electronic position sensitive detectors and target units based on nuclear photographic emulsion films have been developed. The application to the OPERA experiment, that aims at detecting ν μ ν τ oscillations in the CNGS neutrino beam, is reported in this paper. In order to reduce background due to latent tracks collected before installation in the detector, on-site large-scale treatments of the emulsions (''refreshing'') have been applied. Changeable Sheet (CSd) packages, each made of a doublet of emulsion films, have been designed, assembled and coupled to the OPERA target units (''ECC bricks''). A device has been built to print X-ray spots for accurate interconnection both within the CSd and between the CSd and the related ECC brick. Sample emulsion films have been extensively scanned with state-of-the-art automated optical microscopes. Efficient track-matching and powerful background rejection have been achieved in tests with electronically tagged penetrating muons. Further improvement of in-doublet film alignment was obtained by matching the pattern of low-energy electron tracks. The commissioning of the overall OPERA alignment procedure is in progress

Chiral Rayleigh particles discrimination in dynamic dual optical traps

International Nuclear Information System (INIS)

Carretero, Luis; Acebal, Pablo; Blaya, Salvador

2017-01-01

Highlights: • A chiral optical conveyor belt for enantiomeric separation of nanopar-ticles is numerically demonstrated. • Chiral resolution has been theoretically analyzed for chiral spheres immersed in water. • Electromagnetic fields have been designed for obtaining Chiral selective optical tweezers to separate enantiomers in different spatial regions. - Abstract: A chiral optical conveyor belt for enantiomeric separation of nanoparticles is numerically demonstrated by using different types of counter propagating elliptical Laguerre Gaussian beams with different beam waist and topological charge. The analysis of chiral resolution has been made for particles immersed in water demonstrating that in the analyzed conditions one type of enantiomer is trapped in a deep potential and the others are transported by the chiral conveyor toward another trap located in a different geometrical region.

Elve Doublets: The Ionospheric Fingerprints of Compact Intracloud Discharges

Science.gov (United States)

da Silva, C. L.; Marshall, R. A.; Pasko, V. P.

2015-12-01

Compact intracloud discharges (CIDs) persist to date as one of the most mysterious lightning manifestations. CIDs are known to be the strongest natural sources of radio-frequency radiation on Earth. At VHF frequencies, approximately above 30 MHz, their emitted power is ten times stronger than that of other lightning processes. The well-known strength of CIDs in VHF contrasts with the lack of substantial optical measurements. CID's VLF/LF electric field change waveforms resemble one full cycle of a distorted sine function, with the first half-cycle being (a few times) larger-amplitude and shorter-duration than the second. For this reason CIDs have been dubbed narrow bipolar events (NBEs). NBE waveshapes are strikingly similar to the largest initial breakdown pulses (IBPs) that occur during the earlier stages of a conventional lightning flash, called classic IBPs. The similarity between classic IBP and NBE far-field waveforms, combined with the fact that positive-polarity NBEs frequently appear as the first event in an otherwise regular positive intracloud discharge, may be indicative that the source of these two E-field pulse types share the same physical mechanism inside thunderclouds [da Silva and Pasko, JGR, 120, 4989-5009, 2015]. In this presentation, we introduce a novel way to investigate CIDs. We show evidence that CIDs can produce an unique ionospheric signature, named "elve doublets". These signatures are characterized by a pair of elves separated in time by 80-160 microseconds. Our analysis combines fast photometric elve data, equivalent-transmission-line models to describe the dynamics of CID source currents, and FDTD modeling of electromagnetic wave propagation in the Earth-ionosphere waveguide accounting for its nonlinear interaction with the lower ionosphere [Marshall et al., GRL, 42, 2015, doi:10.1002/2015GL064862]. We show that typical (negative-polarity) CID altitudes, between 14-22 km, explain the time delay observed in elve doublets, where the

Beta and current limits in the Doublet III tokamak

International Nuclear Information System (INIS)

Strait, E.J.; Chu, M.S.; Jahns, G.L.

1986-04-01

Neutral-beam heated discharges in Doublet III exhibit an operational beta limit, β/sub T/(%) less than or equal to 3.5 I(MA)/a(m)B(T), in good agreement with several theoretical predictions for ideal external kink or ballooning modes. These theories predict that the β limit has no explicit dependence on plasma shape (for nominal dee shapes). This aspect of the theory was confirmed in Doublet III by varying the elongation (kappa) from 1.0 to 1.6 and the triangularity (delta) from -0.1 to 0.9 and finding in all cases the same β limit. The maximum achievable beta thus depends on the minimum achievable value of the safety factor q. In Doublet III, the operational current limit is given by q greater than or equal to 1.7 for limiter-defined discharges and q greater than or equal to 2.7 for separatrix-defined discharges. Operation with q approx.2 was achieved for 1.0 less than or equal to kappa less than or equal to 1.6. Both β and q limits are characterized by major disruptions which usually terminate the discharge. In both cases, the disruptions often have a precursor oscillation with toroidal mode number n = 1, poloidal mode number m = 2 or 3, a frequency of zero to a few kHz, and a growth time on the order of a millisecond. These observations suggest that the proximate cause of these disruptions is a kink or tearing mode, pressure-driven in one case and current-driven in the other. Theoretical analyses of discharges at both limits will be compared. Modes with a high toroidal mode number, 3 less than or equal to n less than or equal to 5, and ballooning character have been observed near the β/sub T/ limit. These modes do not appear to be closely connected with the disruptions. Heating efficiency, ΔW/ΔP, remains constant up to the limiting disruption. Fishbone modes appear to be mainly a feature of high β/sub p/ operation and not connected to the β/sub T/ limit

Chiral anomaly, bosonization and fractional charge

International Nuclear Information System (INIS)

Mignaco, J.A.; Rego Monteiro, M.A. do.

1984-01-01

A method to evaluate the Jacobian of chiral rotations, regulating determinants through the proper time method and using Seeley's asymptotic expansion is presented. With this method the chiral anomaly ofr ν=4,6 dimensions is computed easily, bosonization of some massless two-dimensional models is discussed and the problem of charge fractionization is handled. Besides, the general validity of Fujikawa's approach to regulate the Jacobian of chiral rotations with non-hermitean operators is commented. (Author) [pt

Supersymmetry and the chiral Schwinger model

International Nuclear Information System (INIS)

Amorim, R.; Das, A.

1998-01-01

We have constructed the N= (1) /(2) supersymmetric general Abelian model with asymmetric chiral couplings. This leads to a N= (1) /(2) supersymmetrization of the Schwinger model. We show that the supersymmetric general model is plagued with problems of infrared divergence. Only the supersymmetric chiral Schwinger model is free from such problems and is dynamically equivalent to the chiral Schwinger model because of the peculiar structure of the N= (1) /(2) multiplets. copyright 1998 The American Physical Society

Chiral Tunnelling in Twisted Graphene Bilayer

OpenAIRE

He, Wen-Yu; Chu, Zhao-Dong; He, Lin

2013-01-01

The perfect transmission in graphene monolayer and the perfect reflection in Bernal graphene bilayer for electrons incident in the normal direction of a potential barrier are viewed as two incarnations of the Klein paradox. Here we show a new and unique incarnation of the Klein paradox. Owing to the different chiralities of the quasiparticles involved, the chiral fermions in twisted graphene bilayer shows adjustable probability of chiral tunnelling for normal incidence: they can be changed fr...

Electromagnetic couplings of the chiral perturbation theory Lagrangian from the perturbative chiral quark model

International Nuclear Information System (INIS)

Lyubovitskij, V.E.; Gutsche, Th.; Faessler, Amand; Mau, R. Vinh

2002-01-01

We apply the perturbative chiral quark model to the study of the low-energy πN interaction. Using an effective chiral Lagrangian we reproduce the Weinberg-Tomozawa result for the S-wave πN scattering lengths. After inclusion of the photon field we give predictions for the electromagnetic O(p 2 ) low-energy couplings of the chiral perturbation theory effective Lagrangian that define the electromagnetic mass shifts of nucleons and first-order (e 2 ) radiative corrections to the πN scattering amplitude. Finally, we estimate the leading isospin-breaking correction to the strong energy shift of the π - p atom in the 1s state, which is relevant for the experiment 'pionic hydrogen' at PSI

Pion polarizability in a chiral quark model

International Nuclear Information System (INIS)

Volkov, M.K.; Ehbert, D.

1980-01-01

The pion polarizability is calculated in a chiral meson-quark model at the one-loop level. The results are in complete agreement with earlier ones obtained within a chiral meson-baryon theory. A critical discussion of a recent paper by Lanta and Tarrach is given. The results of the paper give evidence to the nonlinear chiral Lagrangian favour

Intelligent Chiral Sensing Based on Supramolecular and Interfacial Concepts

Directory of Open Access Journals (Sweden)

Hironori Izawa

2010-07-01

Full Text Available Of the known intelligently-operating systems, the majority can undoubtedly be classed as being of biological origin. One of the notable differences between biological and artificial systems is the important fact that biological materials consist mostly of chiral molecules. While most biochemical processes routinely discriminate chiral molecules, differentiation between chiral molecules in artificial systems is currently one of the challenging subjects in the field of molecular recognition. Therefore, one of the important challenges for intelligent man-made sensors is to prepare a sensing system that can discriminate chiral molecules. Because intermolecular interactions and detection at surfaces are respectively parts of supramolecular chemistry and interfacial science, chiral sensing based on supramolecular and interfacial concepts is a significant topic. In this review, we briefly summarize recent advances in these fields, including supramolecular hosts for color detection on chiral sensing, indicator-displacement assays, kinetic resolution in supramolecular reactions with analyses by mass spectrometry, use of chiral shape-defined polymers, such as dynamic helical polymers, molecular imprinting, thin films on surfaces of devices such as QCM, functional electrodes, FET, and SPR, the combined technique of magnetic resonance imaging and immunoassay, and chiral detection using scanning tunneling microscopy and cantilever technology. In addition, we will discuss novel concepts in recent research including the use of achiral reagents for chiral sensing with NMR, and mechanical control of chiral sensing. The importance of integration of chiral sensing systems with rapidly developing nanotechnology and nanomaterials is also emphasized.

Enantioseparation and chiral recognition mechanism of new chiral derivatives of xanthones on macrocyclic antibiotic stationary phases.

Science.gov (United States)

Fernandes, Carla; Tiritan, Maria Elizabeth; Cass, Quezia; Kairys, Visvaldas; Fernandes, Miguel Xavier; Pinto, Madalena

2012-06-08

A chiral HPLC method using four macrocyclic antibiotic chiral stationary phases (CSPs) has been investigated for determination of the enantiomeric purity of fourteen new chiral derivatives of xanthones (CDXs). The separations were performed with the CSPs Chirobiotic T, Chirobiotic TAG, Chirobiotic V and Chirobiotic R under multimodal elution conditions (normal-phase, reversed-phase and polar ionic mode). The analyses were performed at room temperature in isocratic mode and UV and CD detection at a wavelength of 254 nm. The best enantioselectivity and resolution were achieved on Chirobiotic R and Chirobiotic T CSPs, under normal elution conditions, with R(S) ranging from 1.25 to 2.50 and from 0.78 to 2.06, respectively. The optimized chromatographic conditions allowed the determination of the enantiomeric ratio of eight CDXs, always higher than 99%. In order to better understand the chromatographic behavior at a molecular level, and the structural features associated with the chiral recognition mechanism, computational studies by molecular docking were carried out using VDock. These studies shed light on the mechanisms involved in the enantioseparation for this important class of chiral compounds. Copyright © 2012 Elsevier B.V. All rights reserved.

Chiral symmetry breaking and confinement - solutions of relativistic wave equations

International Nuclear Information System (INIS)

Murugesan, P.

1983-01-01

In this thesis, an attempt is made to explore the question whether confinement automatically leads to chiral symmetry breaking. While it should be accepted that chiral symmetry breaking manifests in nature in the absence of scalar partners of pseudoscalar mesons, it does not necessarily follow that confinement should lead to chiral symmetry breaking. If chiral conserving forces give rise to observed spectrum of hadrons, then the conjuncture that confinement is responsible for chiral symmetry breaking is not valid. The method employed to answer the question whether confinement leads to chiral symmetry breaking or not is to solve relativistic wave equations by introducing chiral conserving as well as chiral breaking confining potentials and compare the results with experimental observations. It is concluded that even though chiral symmetry is broken in nature, confinement of quarks need not be the cause of it

Topological chiral phonons in center-stacked bilayer triangle lattices

Science.gov (United States)

Xu, Xifang; Zhang, Wei; Wang, Jiaojiao; Zhang, Lifa

2018-06-01

Since chiral phonons were found in an asymmetric two-dimensional hexagonal lattice, there has been growing interest in the study of phonon chirality, which were experimentally verified very recently in monolayer tungsten diselenide (2018 Science 359 579). In this work, we find chiral phonons with nontrivial topology in center-stacked bilayer triangle lattices. At the Brillouin-zone corners, (), circularly polarized phonons and nonzero phonon Berry curvature are observed. Moreover, we find that the phonon chirality remain robust with changing sublattice mass ratio and interlayer coupling. The chiral phonons at the valleys are demonstrated in doubler-layer sodium chloride along the [1 1 1] direction. We believe that the findings on topological chiral phonons in triangle lattices will give guidance in the study of chiral phonons in real materials and promote the phononic applications.

Minimally doubled fermions and spontaneous chiral symmetry breaking

Directory of Open Access Journals (Sweden)

Osmanaj (Zeqirllari Rudina

2018-01-01

Full Text Available Chiral symmetry breaking in massless QCD is a very important feature in the current understanding of low energy physics. Low - lying Dirac modes are suitable to help us understand the spontaneous chiral symmetry breaking, since the formation of a non zero chiral condensate is an effect of their accumulation near zero. The Banks – Casher relation links the spectral density of the Dirac operator to the condensate with an identity that can be read in both directions. In this work we propose a spectral method to achieve a reliable determination of the density of eigenvalues of Dirac operator near zero using the Gauss – Lanczos quadrature. In order to understand better the dynamical chiral symmetry breaking and use the method we propose, we have chosen to work with minimally doubled fermions. These kind of fermions have been proposed as a strictly local discretization of the QCD fermions action, which preserves chiral symmetry at finite cut-off. Being chiral fermions, is easier to work with them and their low - lying Dirac modes and to understand the dynamical spontaneous chiral symmetry breaking.

Minimally doubled fermions and spontaneous chiral symmetry breaking

Science.gov (United States)

Osmanaj (Zeqirllari), Rudina; Hyka (Xhako), Dafina

2018-03-01

Chiral symmetry breaking in massless QCD is a very important feature in the current understanding of low energy physics. Low - lying Dirac modes are suitable to help us understand the spontaneous chiral symmetry breaking, since the formation of a non zero chiral condensate is an effect of their accumulation near zero. The Banks - Casher relation links the spectral density of the Dirac operator to the condensate with an identity that can be read in both directions. In this work we propose a spectral method to achieve a reliable determination of the density of eigenvalues of Dirac operator near zero using the Gauss - Lanczos quadrature. In order to understand better the dynamical chiral symmetry breaking and use the method we propose, we have chosen to work with minimally doubled fermions. These kind of fermions have been proposed as a strictly local discretization of the QCD fermions action, which preserves chiral symmetry at finite cut-off. Being chiral fermions, is easier to work with them and their low - lying Dirac modes and to understand the dynamical spontaneous chiral symmetry breaking.

Sum-Frequency Generation from Chiral Media and Interfaces

Energy Technology Data Exchange (ETDEWEB)

Ji, Na [Univ. of California, Berkeley, CA (United States)

2006-02-13

Sum frequency generation (SFG), a second-order nonlinear optical process, is electric-dipole forbidden in systems with inversion symmetry. As a result, it has been used to study chiral media and interfaces, systems intrinsically lacking inversion symmetry. This thesis describes recent progresses in the applications of and new insights into SFG from chiral media and interfaces. SFG from solutions of chiral amino acids is investigated, and a theoretical model explaining the origin and the strength of the chiral signal in electronic-resonance SFG spectroscopy is discussed. An interference scheme that allows us to distinguish enantiomers by measuring both the magnitude and the phase of the chiral SFG response is described, as well as a chiral SFG microscope producing chirality-sensitive images with sub-micron resolution. Exploiting atomic and molecular parity nonconservation, the SFG process is also used to solve the Ozma problems. Sum frequency vibrational spectroscopy is used to obtain the adsorption behavior of leucine molecules at air-water interfaces. With poly(tetrafluoroethylene) as a model system, we extend the application of this surface-sensitive vibrational spectroscopy to fluorine-containing polymers.

Sum-Frequency Generation from Chiral Media and Interfaces

International Nuclear Information System (INIS)

Ji, Na

2006-01-01

Sum frequency generation (SFG), a second-order nonlinear optical process, is electric-dipole forbidden in systems with inversion symmetry. As a result, it has been used to study chiral media and interfaces, systems intrinsically lacking inversion symmetry. This thesis describes recent progresses in the applications of and new insights into SFG from chiral media and interfaces. SFG from solutions of chiral amino acids is investigated, and a theoretical model explaining the origin and the strength of the chiral signal in electronic-resonance SFG spectroscopy is discussed. An interference scheme that allows us to distinguish enantiomers by measuring both the magnitude and the phase of the chiral SFG response is described, as well as a chiral SFG microscope producing chirality-sensitive images with sub-micron resolution. Exploiting atomic and molecular parity nonconservation, the SFG process is also used to solve the Ozma problems. Sum frequency vibrational spectroscopy is used to obtain the adsorption behavior of leucine molecules at air-water interfaces. With poly(tetrafluoroethylene) as a model system, we extend the application of this surface-sensitive vibrational spectroscopy to fluorine-containing polymers

Inversion of Supramolecular Chirality by Sonication-Induced Organogelation

Science.gov (United States)

Maity, Sibaprasad; Das, Priyadip; Reches, Meital

2015-01-01

Natural helical structures have inspired the formation of well-ordered peptide-based chiral nanostructures in vitro. These structures have drawn much attention owing to their diverse applications in the area of asymmetric catalysts, chiral photonic materials, and nanoplasmonics. The self-assembly of two enantiomeric fluorinated aromatic dipeptides into ordered chiral fibrillar nanostructures upon sonication is described. These fibrils form organogels. Our results clearly indicate that fluorine-fluorine interactions play an important role in self-assembly. Circular dichroism analysis revealed that both peptides (peptides 1 and 2), containing two fluorines, depicted opposite cotton effects in their monomeric form compared with their aggregated form. This shows that supramolecular chirality inversion took place during the stimuli-responsive self-aggregation process. Conversely, peptide 3, containing one fluorine, did not exhibit chirality inversion in sonication-induced organogelation. Therefore, our results clearly indicate that fluorination plays an important role in the organogelation process of these aromatic dipeptides. Our findings may have broad implications regarding the design of chiral nanostructures for possible applications such as chiroptical switches, asymmetric catalysis, and chiral recognitions. PMID:26553508

The inert doublet model in the light of Fermi-LAT gamma-ray data: a global fit analysis

Science.gov (United States)

Eiteneuer, Benedikt; Goudelis, Andreas; Heisig, Jan

2017-09-01

We perform a global fit within the inert doublet model taking into account experimental observables from colliders, direct and indirect dark matter searches and theoretical constraints. In particular, we consider recent results from searches for dark matter annihilation-induced gamma-rays in dwarf spheroidal galaxies and relax the assumption that the inert doublet model should account for the entire dark matter in the Universe. We, moreover, study in how far the model is compatible with a possible dark matter explanation of the so-called Galactic center excess. We find two distinct parameter space regions that are consistent with existing constraints and can simultaneously explain the excess: One with dark matter masses near the Higgs resonance and one around 72 GeV where dark matter annihilates predominantly into pairs of virtual electroweak gauge bosons via the four-vertex arising from the inert doublet's kinetic term. We briefly discuss future prospects to probe these scenarios.

The inert doublet model in the light of Fermi-LAT gamma-ray data: a global fit analysis

Energy Technology Data Exchange (ETDEWEB)

Eiteneuer, Benedikt; Heisig, Jan [RWTH Aachen University, Institute for Theoretical Particle Physics and Cosmology, Aachen (Germany); Goudelis, Andreas [UMR 7589 CNRS and UPMC, Laboratoire de Physique Theorique et Hautes Energies (LPTHE), Paris (France)

2017-09-15

We perform a global fit within the inert doublet model taking into account experimental observables from colliders, direct and indirect dark matter searches and theoretical constraints. In particular, we consider recent results from searches for dark matter annihilation-induced gamma-rays in dwarf spheroidal galaxies and relax the assumption that the inert doublet model should account for the entire dark matter in the Universe. We, moreover, study in how far the model is compatible with a possible dark matter explanation of the so-called Galactic center excess. We find two distinct parameter space regions that are consistent with existing constraints and can simultaneously explain the excess: One with dark matter masses near the Higgs resonance and one around 72 GeV where dark matter annihilates predominantly into pairs of virtual electroweak gauge bosons via the four-vertex arising from the inert doublet's kinetic term. We briefly discuss future prospects to probe these scenarios. (orig.)

Asymmetric Michael Addition Mediated by Chiral Ionic Liquids.

Science.gov (United States)

Suzuki, Yumiko

2018-06-01

Chiral ionic liquids with a focus on their applications in asymmetric Michael additions and related reactions were reviewed. The examples were classified on the basis of the mode of asymmetric induction (e.g., external induction/non-covalent interaction or internal induction/covalent bond formation), the roles in reactions (as a solvent or catalyst), and their structural features (e.g., imidazolium-based chiral cations, other chiral oniums; proline derivatives). Most of the reactions with high chiral induction are Michael addition of ketones or aldehydes to chalcones or nitrostyrenes where proline-derived chiral ionic liquids catalyze the reaction through enamine/ iminium formation. Many reports demonstrate the recyclability of ionic liquid-tagged pyrrolidines.

Probing molecular chirality by coherent optical absorption spectra

Energy Technology Data Exchange (ETDEWEB)

Jia, W. Z. [Quantum Optoelectronics Laboratory, School of Physics and Technology, Southwest Jiaotong University, Chengdu 610031 (China); Wei, L. F. [Quantum Optoelectronics Laboratory, School of Physics and Technology, Southwest Jiaotong University, Chengdu 610031 (China); State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

2011-11-15

We propose an approach to sensitively probe the chirality of molecules by measuring their coherent optical-absorption spectra. It is shown that quantum dynamics of the cyclic three-level chiral molecules driven by appropriately designed external fields is total-phase dependent. This will result in chirality-dependent absorption spectra for the probe field. As a consequence, the charality-dependent information in the spectra (such as the locations and relative heights of the characteristic absorption peaks) can be utilized to identify molecular chirality and determinate enantiomer excess (i.e., the percentages of different enantiomers). The feasibility of the proposal with chiral molecules confined in hollow-core photonic crystal fiber is also discussed.

Theoretical study of high-Q Fano resonance and extrinsic chirality in an ultrathin Babinet-inverted metasurface

Science.gov (United States)

Wang, Feng; Wang, Zhengping; Shi, Jinhui

2014-10-01

A high-Q Fano resonance and giant extrinsic chirality have been demonstrated in an ultrathin Babinet-inverted metasurface composed of asymmetrical split ring apertures (ASRAs) perforated through a metal plate based on the full-wave simulations. The performance of the Fano resonance at normal incidence strongly depends on the asymmetry of the ASRA. The quality factor is larger than 1000 and the local field enhancement is an order of 104. For oblique incidence, giant extrinsic chirality can be achieved in the Babinet-inverted metasurface. It reveals a cross-polarization transmission band with a ripple-free peak and also a spectrum split for large angles of incidence. The electromagnetic response of the metasurface can be easily tuned via angles of incidence and asymmetry. The proposed ASRA metasurface is of importance to develop many metamaterial-based devices, such as filters and circular polarizers.

Lattice regularized chiral perturbation theory

International Nuclear Information System (INIS)

Borasoy, Bugra; Lewis, Randy; Ouimet, Pierre-Philippe A.

2004-01-01

Chiral perturbation theory can be defined and regularized on a spacetime lattice. A few motivations are discussed here, and an explicit lattice Lagrangian is reviewed. A particular aspect of the connection between lattice chiral perturbation theory and lattice QCD is explored through a study of the Wess-Zumino-Witten term

Chiral tunneling in a twisted graphene bilayer.

Science.gov (United States)

He, Wen-Yu; Chu, Zhao-Dong; He, Lin

2013-08-09

The perfect transmission in a graphene monolayer and the perfect reflection in a Bernal graphene bilayer for electrons incident in the normal direction of a potential barrier are viewed as two incarnations of the Klein paradox. Here we show a new and unique incarnation of the Klein paradox. Owing to the different chiralities of the quasiparticles involved, the chiral fermions in a twisted graphene bilayer show an adjustable probability of chiral tunneling for normal incidence: they can be changed from perfect tunneling to partial or perfect reflection, or vice versa, by controlling either the height of the barrier or the incident energy. As well as addressing basic physics about how the chiral fermions with different chiralities tunnel through a barrier, our results provide a facile route to tune the electronic properties of the twisted graphene bilayer.

SU(3) chiral symmetry for baryons

International Nuclear Information System (INIS)

Dmitrasinovic, V.

2011-01-01

Three-quark nucleon interpolating fields in QCD have well-defined SU L (3)xSU R (3) and U A (1) chiral transformation properties, viz. [(6,3)+(3,6)], [(3,3-bar)+(3-bar,3)], [(8,1)+(1,8)] and their 'mirror' images. It has been shown (phenomenologically) in Ref. [2] that mixing of the [(6,3)+(3,6)] chiral multiplet with one ordinary ('naive') and one 'mirror' field belonging to the [(3,3-bar)+(3-bar,3)], [(8,1)+(1,8)] multiplets can be used to fit the values of the isovector (g A (3) ) and the flavor-singlet (isoscalar) axial coupling (g A (0) ) of the nucleon and then predict the axial F and D coefficients, or vice versa, in reasonable agreement with experiment. In an attempt to derive such mixing from an effective Lagrangian, we construct all SU L (3)xSU R (3) chirally invariant non-derivative one-meson-baryon interactions and then calculate the mixing angles in terms of baryons' masses. It turns out that there are (strong) selection rules: for example, there is only one non-derivative chirally symmetric interaction between J 1/2 fields belonging to the [(6,3)+(3,6)] and the [(3,3-bar)+(3-bar,3)] chiral multiplets, that is also U A (1) symmetric. We also study the chiral interactions of the [(3,3-bar)+(3-bar,3)] and [(8,1)+(1,8)] nucleon fields. Again, there are selection rules that allow only one off-diagonal non-derivative chiral SU L (3)xSU R (3) interaction of this type, that also explicitly breaks the U A (1) symmetry. We use this interaction to calculate the corresponding mixing angles in terms of baryon masses and fit two lowest lying observed nucleon (resonance) masses, thus predicting the third (J = 1/2, I = 3/2)Δ resonance, as well as one or two flavor-singlet Λ hyperon(s), depending on the type of mixing. The effective chiral Lagrangians derived here may be applied to high density matter calculations.

Interplay of Chiral and Helical States in a Quantum Spin Hall Insulator Lateral Junction

Science.gov (United States)

Calvo, M. R.; de Juan, F.; Ilan, R.; Fox, E. J.; Bestwick, A. J.; Mühlbauer, M.; Wang, J.; Ames, C.; Leubner, P.; Brüne, C.; Zhang, S. C.; Buhmann, H.; Molenkamp, L. W.; Goldhaber-Gordon, D.

2017-12-01

We study the electronic transport across an electrostatically gated lateral junction in a HgTe quantum well, a canonical 2D topological insulator, with and without an applied magnetic field. We control the carrier density inside and outside a junction region independently and hence tune the number and nature of 1D edge modes propagating in each of those regions. Outside the bulk gap, the magnetic field drives the system to the quantum Hall regime, and chiral states propagate at the edge. In this regime, we observe fractional plateaus that reflect the equilibration between 1D chiral modes across the junction. As the carrier density approaches zero in the central region and at moderate fields, we observe oscillations in the resistance that we attribute to Fabry-Perot interference in the helical states, enabled by the broken time reversal symmetry. At higher fields, those oscillations disappear, in agreement with the expected absence of helical states when band inversion is lifted.

The synthesis and characterization of novel brush-type chiral stationary phase based on terpenoid selector for resolution of chiral drugs

Directory of Open Access Journals (Sweden)

Wang Dao-Cai

2016-01-01

Full Text Available In the light of the chiral resolution mechanism and structures of brush-type CSP, a new chiral selector 4′-carboxyl-1′-ursolic methyl ester-3β-yl-benzoate has been prepared. Then the terpenoid chiral selector was covalently linked to 3-aminopropyl silica gel. Its structure identification data are provided by 1H NMR, MS and elementary analysis. The enantiodiscriminating capability of the brush-type CSP was evaluated by static adsorption experiment with methyl mandelate, aniline derivative of mandelic acid, benzoin and ibuprofen. Experimental results demonstrated that the chiral selector has selectivity, and the enantiomers of methyl mandelate and ibuprofen could be separated on the CSP, which indicated that the novel brush-type CSP possess a bright prospects for chiral separation potentially.

Chiral charge erasure via thermal fluctuations of magnetic helicity

International Nuclear Information System (INIS)

Long, Andrew J.; Sabancilar, Eray

2016-01-01

We consider a relativistic plasma of fermions coupled to an Abelian gauge field and carrying a chiral charge asymmetry, which might arise in the early Universe through baryogenesis. It is known that on large length scales, λ≳1/(αμ_5), the chiral anomaly opens an instability toward the erasure of chiral charge and growth of magnetic helicity. Here the chemical potential μ_5 parametrizes the chiral asymmetry and α is the fine-structure constant. We study the process of chiral charge erasure through the thermal fluctuations of magnetic helicity and contrast with the well-studied phenomenon of Chern-Simons number diffusion. Through the fluctuation-dissipation theorem we estimate the amplitude and time scale of helicity fluctuations on the length scale λ, finding δ H∼λT and τ∼αλ"3T"2 for a relativistic plasma at temperature T. We argue that the presence of a chiral asymmetry allows the helicity to grow diffusively for a time t∼T"3/(α"5μ_5"4) until it reaches an equilibrium value H∼μ_5T"2/α, and the chiral asymmetry is partially erased. If the chiral asymmetry is small, μ_5< T/α, this avenue for chiral charge erasure is found to be slower than the chiral magnetic effect for which t∼T/(α"3μ_5"2). This mechanism for chiral charge erasure can be important for the hypercharge sector of the Standard Model as well as extensions including U(1) gauge interactions, such as asymmetric dark matter models.

FN-2HDM: Two Higgs Doublet Models with Froggatt-Nielsen symmetry

Energy Technology Data Exchange (ETDEWEB)

Dery, Avital; Nir, Yosef [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Herzl 234, Rehovot 76100 (Israel)

2017-04-03

We embed Two Higgs Doublet Models (2HDMs) in the Froggatt Nielsen (FN) framework. We find that the approximate FN symmetry predicts i) approximate Natural Flavor Conservation (NFC) of Types II or IV in the Yukawa sector, and ii) approximate Peccei-Quinn (PQ) symmetry in the scalar sector. We discuss the phenomenological consequences of these features.

A chiral aluminum solvating agent (CASA) for 1H NMR chiral analysis of alcohols at low temperature.

Science.gov (United States)

Seo, Min-Seob; Jang, Sumin; Kim, Hyunwoo

2018-03-16

A chiral aluminum solvating agent (CASA) was demonstrated to be a general and efficient reagent for 1H NMR chiral analysis of alcohols. The sodium salt of the CASA (CASA-Na) showed a complete baseline peak separation of the hydroxyl group for various chiral alcohols including primary, secondary, and tertiary alcohols with alkyl and aryl substituents in CD3CN. Due to the weak intermolecular interaction, 1H NMR measurement at low temperature (-40 to 10 °C) was required.

Generalized chiral perturbation theory

International Nuclear Information System (INIS)

Knecht, M.; Stern, J.

1994-01-01

The Generalized Chiral Perturbation Theory enlarges the framework of the standard χPT (Chiral Perturbation Theory), relaxing certain assumptions which do not necessarily follow from QCD or from experiment, and which are crucial for the usual formulation of the low energy expansion. In this way, experimental tests of the foundations of the standard χPT become possible. Emphasis is put on physical aspects rather than on formal developments of GχPT. (author). 31 refs

Chiral separation of substituted phenylalanine analogues using chiral palladium phosphine complexes with enantioselective liquid-liquid extraction

NARCIS (Netherlands)

Verkuijl, B.J.V.; Schuur, B.; Minnaard, A.J.; Vries, de J.G.; Feringa, B.L.

2010-01-01

Chiral palladium phosphine complexes have been employed in the chiral separation of amino acids and phenylalanine analogues in particular. The use of (S)-xylyl-BINAP as a ligand for the palladium complex in enantioselective liquid–liquid extraction allowed the separation of the phenylalanine

Laminar and Turbulent Dynamos in Chiral Magnetohydrodynamics. I. Theory

Energy Technology Data Exchange (ETDEWEB)

Rogachevskii, Igor; Kleeorin, Nathan [Department of Mechanical Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105 (Israel); Ruchayskiy, Oleg [Discovery Center, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen (Denmark); Boyarsky, Alexey [Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, Niels Bohrweg 2, 2333 CA Leiden (Netherlands); Fröhlich, Jürg [Institute of Theoretical Physics, ETH Hönggerberg, CH-8093 Zurich (Switzerland); Brandenburg, Axel; Schober, Jennifer, E-mail: gary@bgu.ac.il [Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)

2017-09-10

The magnetohydrodynamic (MHD) description of plasmas with relativistic particles necessarily includes an additional new field, the chiral chemical potential associated with the axial charge (i.e., the number difference between right- and left-handed relativistic fermions). This chiral chemical potential gives rise to a contribution to the electric current density of the plasma ( chiral magnetic effect ). We present a self-consistent treatment of the chiral MHD equations , which include the back-reaction of the magnetic field on a chiral chemical potential and its interaction with the plasma velocity field. A number of novel phenomena are exhibited. First, we show that the chiral magnetic effect decreases the frequency of the Alfvén wave for incompressible flows, increases the frequencies of the Alfvén wave and of the fast magnetosonic wave for compressible flows, and decreases the frequency of the slow magnetosonic wave. Second, we show that, in addition to the well-known laminar chiral dynamo effect, which is not related to fluid motions, there is a dynamo caused by the joint action of velocity shear and chiral magnetic effect. In the presence of turbulence with vanishing mean kinetic helicity, the derived mean-field chiral MHD equations describe turbulent large-scale dynamos caused by the chiral alpha effect, which is dominant for large fluid and magnetic Reynolds numbers. The chiral alpha effect is due to an interaction of the chiral magnetic effect and fluctuations of the small-scale current produced by tangling magnetic fluctuations (which are generated by tangling of the large-scale magnetic field by sheared velocity fluctuations). These dynamo effects may have interesting consequences in the dynamics of the early universe, neutron stars, and the quark–gluon plasma.

Laminar and Turbulent Dynamos in Chiral Magnetohydrodynamics. I. Theory

International Nuclear Information System (INIS)

Rogachevskii, Igor; Kleeorin, Nathan; Ruchayskiy, Oleg; Boyarsky, Alexey; Fröhlich, Jürg; Brandenburg, Axel; Schober, Jennifer

2017-01-01

The magnetohydrodynamic (MHD) description of plasmas with relativistic particles necessarily includes an additional new field, the chiral chemical potential associated with the axial charge (i.e., the number difference between right- and left-handed relativistic fermions). This chiral chemical potential gives rise to a contribution to the electric current density of the plasma ( chiral magnetic effect ). We present a self-consistent treatment of the chiral MHD equations , which include the back-reaction of the magnetic field on a chiral chemical potential and its interaction with the plasma velocity field. A number of novel phenomena are exhibited. First, we show that the chiral magnetic effect decreases the frequency of the Alfvén wave for incompressible flows, increases the frequencies of the Alfvén wave and of the fast magnetosonic wave for compressible flows, and decreases the frequency of the slow magnetosonic wave. Second, we show that, in addition to the well-known laminar chiral dynamo effect, which is not related to fluid motions, there is a dynamo caused by the joint action of velocity shear and chiral magnetic effect. In the presence of turbulence with vanishing mean kinetic helicity, the derived mean-field chiral MHD equations describe turbulent large-scale dynamos caused by the chiral alpha effect, which is dominant for large fluid and magnetic Reynolds numbers. The chiral alpha effect is due to an interaction of the chiral magnetic effect and fluctuations of the small-scale current produced by tangling magnetic fluctuations (which are generated by tangling of the large-scale magnetic field by sheared velocity fluctuations). These dynamo effects may have interesting consequences in the dynamics of the early universe, neutron stars, and the quark–gluon plasma.

A nonlocal model of chiral dynamics

International Nuclear Information System (INIS)

Holdom, B.; Terning, J.; Verbeek, K.

1989-01-01

We consider a nonlocal generalization of the nonlinear σ model. Our chirally symmetric model couples quarks with self-energy Σ(p) to Goldstone bosons (GBs). By integrating out the quarks we obtain a chiral lagrangian, the parameters of which are finite integrals of Σ(p). We find that chiral symmetry is not sufficient to derive the well-known Pagels-Stokar formula for the GB decay constant. We reproduce the Wess-Zumino term and we illustrate the dependence of other four derivative coefficients on Σ(p). (orig.)

Chirality and chiroptical properties of amyloid fibrils.

Science.gov (United States)

Dzwolak, Wojciech

2014-09-01

Chirality of amyloid fibrils-linear beta-sheet-rich aggregates of misfolded protein chains-often manifests in morphological traits such as helical twist visible in atomic force microscopy and in chiroptical properties accessible to vibrational circular dichroism (VCD). According to recent studies the relationship between molecular chirality of polypeptide building blocks and superstructural chirality of amyloid fibrils may be more intricate and less deterministic than previously assumed. Several puzzling experimental findings have put into question earlier intuitive ideas on: 1) the bottom-up chirality transfer upon amyloidogenic self-assembly, and 2) the structural origins of chiroptical properties of protein aggregates. For example, removal of a single amino acid residue from an amyloidogenic all-L peptide was shown to reverse handedness of fibrils. On the other hand, certain types of amyloid aggregates revealed surprisingly strong VCD spectra with the sign and shape dependent on the conditions of fibrillation. Hence, microscopic and chiroptical studies have highlighted chirality as one more aspect of polymorphism of amyloid fibrils. This brief review is intended to outline the current state of research on amyloid-like fibrils from the perspective of their structural and superstructural chirality and chiroptical properties. © 2014 Wiley Periodicals, Inc.

Asymmetric Michael Addition Mediated by Chiral Ionic Liquids

Science.gov (United States)

Suzuki, Yumiko

2018-01-01

Chiral ionic liquids with a focus on their applications in asymmetric Michael additions and related reactions were reviewed. The examples were classified on the basis of the mode of asymmetric induction (e.g., external induction/non-covalent interaction or internal induction/covalent bond formation), the roles in reactions (as a solvent or catalyst), and their structural features (e.g., imidazolium-based chiral cations, other chiral oniums; proline derivatives). Most of the reactions with high chiral induction are Michael addition of ketones or aldehydes to chalcones or nitrostyrenes where proline-derived chiral ionic liquids catalyze the reaction through enamine/ iminium formation. Many reports demonstrate the recyclability of ionic liquid-tagged pyrrolidines. PMID:29861702

Chiroptical studies on supramolecular chirality of molecular aggregates.

Science.gov (United States)

Sato, Hisako; Yajima, Tomoko; Yamagishi, Akihiko

2015-10-01

The attempts of applying chiroptical spectroscopy to supramolecular chirality are reviewed with a focus on vibrational circular dichroism (VCD). Examples were taken from gels, solids, and monolayers formed by low-molecular mass weight chiral gelators. Particular attention was paid to a group of gelators with perfluoroalkyl chains. The effects of the helical conformation of the perfluoroalkyl chains on the formation of chiral architectures are reported. It is described how the conformation of a chiral gelator was determined by comparing the experimental and theoretical VCD spectra together with a model proposed for the molecular aggregation in fibrils. The results demonstrate the potential utility of the chiroptical method in analyzing organized chiral aggregates. © 2015 Wiley Periodicals, Inc.

Three-dimensional magnetotelluric imaging of the 1997 Kagoshima earthquake doublet, Southwest Japan

Science.gov (United States)

Asamori, K.; Makuuchi, A.; Umeda, K.

2013-12-01

The 1997 Kagoshima earthquake doublet struck on unrecognized active faults lacking clear surface expression where very few large earthquakes have occurred. Two shallow moderate earthquakes occurred in the northwestern part of Kagoshima province, on March 26 (Mw 6.1) and May 13 (Mw 6.0) in 1997, both followed by intensive aftershock sequences. Aftershock distribution of the 1997 earthquake doublet reflects complicated rupture process attributed to the geological (rheological) conditions and coupling of hydraulic pressure as well as tectonic shear stress. For advanced understanding of dynamic interactions between fluids and faulting, it is imperative to obtain three-dimensional (3-D) images of the electrical resistivity structure around the seismogenic faults. In this study, we conduct magnetotelluric (MT) soundings in and around the source region of the 1997 Kagoshima earthquake sequence and perform a 3-D inversion of wideband MT data above a depth of 30 km. MT stations were deployed around the aftershock area of the 1997 Kagoshima earthquake. All of 42 MT sites were set up in the land area. The data were collected using five component (three magnetic and two telluric components) wide-band MT instruments (Phoenix MTU-5 system) in February, 2013. The data were acquired in the frequency range from 0.000343 to 320 Hz. The recording duration ranged from 2 to 8 days. As the cultural noises severely affect the measurements, the time series analysis focused on the nocturnal data when there were fewer noise. A simultaneous remote reference measurement was carried out at the Sawauchi site (1300 km northeast of the study area). Using the remote reference technique (Gamble et al., 1979), we were able to reduce the unfavorable cultural noises. The observed apparent resistivity and phase data were inverted simultaneously using the 3-D inversion code of Sasaki (2004). In this inversion, the 3-D blocks were set up in the crust and upper mantle. These block size in the horizontal

Chiral dynamics and peripheral transverse densities

Energy Technology Data Exchange (ETDEWEB)

Granados, Carlos G. [Uppsala University (Sweden); Weiss, Christian [JLAB, Newport News, VA (United States)

2014-01-01

In the partonic (or light-front) description of relativistic systems the electromagnetic form factors are expressed in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral components of nucleon structure as the peripheral densities at transverse distances b = O(M{sub {pi}}{sup -1}) and compute them in a parametrically controlled manner. A dispersion relation connects the large-distance behavior of the transverse charge and magnetization densities to the spectral functions of the Dirac and Pauli form factors near the two--pion threshold at timelike t = 4 M{ sub {pi}}{sup 2}, which can be computed in relativistic chiral effective field theory. Using the leading-order approximation we (a) derive the asymptotic behavior (Yukawa tail) of the isovector transverse densities in the "chiral" region b = O(M{sub {pi}}{sup -1}) and the "molecular" region b = O(M{sub N}{sup 2}/M{sub {pi}}{sup 3}); (b) perform the heavy-baryon expansion of the transverse densities; (c) explain the relative magnitude of the peripheral charge and magnetization densities in a simple mechanical picture; (d) include Delta isobar intermediate states and study the peripheral transverse densities in the large-N{ sub c} limit of QCD; (e) quantify the region of transverse distances where the chiral components of the densities are numerically dominant; (f) calculate the chiral divergences of the b{sup 2}-weighted moments of the isovector transverse densities (charge and anomalous magnetic radii) in the limit M{sub {pi}} -> 0 and determine their spatial support. Our approach provides a concise formulation of the spatial structure of the nucleon's chiral component and offers new insights into basic properties of the chiral expansion. It relates the information extracted from low-t elastic form factors to the generalized parton distributions probed in peripheral high-energy scattering processes.

Top-bottom doublet in the sphaleron background

CERN Document Server

Moreno, J M; Quirós, Mariano

1995-01-01

We consider the top-bottom doublet in the background of the sphaleron for the realistic case of large non-degeneracy of fermion masses, in particular m_b=5 GeV and m_t=175 GeV. We propose an axially symmetric (r,\\theta)-dependent ansatz for fermion fields and investigate the effects of the non-degeneracy on them. The exact solution is described, with an error less than 0.01\\%, by a set of ten radial functions. We also propose an approximate solution, in the m_b/m_t\\rightarrow 0 limit, with an error {\\cal O}(m_b/m_t). We have found that the effects of non-degeneracy provide a \\theta-dependence typically \\sim 10\\%.

Theory of singlet-doublet excitations in praseodymium

International Nuclear Information System (INIS)

Bak, P.

1975-10-01

The magnetic excitation spectrum in a paramagnetic singlet-doublet system is calculated using a diagrammatic high density expansion technique. The lowest order diagrams, which correspond to the random phase approximation (RPA), give a detailed description of the wave vector and temperature dependence of the four exciton modes in praseodymium in terms of a Hamiltonian including isotropic Heisenberg exchange interactions and anisotropic, dipolar-like interactions. The leading contributions to the linewidths of the excitations are obtained by extending the 1/Z expansion of the generalized susceptibility propagators one order beyond the random phase approximation. This damping corresponds to spin wave scattering on single-site fluctuations. The theoretical spectral functions are in detailed agreement with experiment

Intrinsic Chirality Origination in Carbon Nanotubes.

Science.gov (United States)

Pierce, Neal; Chen, Gugang; P Rajukumar, Lakshmy; Chou, Nam Hawn; Koh, Ai Leen; Sinclair, Robert; Maruyama, Shigeo; Terrones, Mauricio; Harutyunyan, Avetik R

2017-10-24

Elucidating the origin of carbon nanotube chirality is key for realizing their untapped potential. Currently, prevalent theories suggest that catalyst structure originates chirality via an epitaxial relationship. Here we studied chirality abundances of carbon nanotubes grown on floating liquid Ga droplets, which excludes the influence of catalyst features, and compared them with abundances grown on solid Ru nanoparticles. Results of growth on liquid droplets bolsters the intrinsic preference of carbon nuclei toward certain chiralities. Specifically, the abundance of the (11,1)/χ = 4.31° tube can reach up to 95% relative to (9,4)/χ = 17.48°, although they have exactly the same diameter, (9.156 Å). However, the comparative abundances for the pair, (19,3)/χ = 7.2° and (17,6)/χ = 14.5°, with bigger diameter, (16.405 Å), fluctuate depending on synthesis temperature. The abundances of the same pairs of tubes grown on floating solid polyhedral Ru nanoparticles show completely different trends. Analysis of abundances in relation to nucleation probability, represented by a product of the Zeldovich factor and the deviation interval of a growing nuclei from equilibrium critical size, explain the findings. We suggest that the chirality in the nanotube in general is a result of interplay between intrinsic preference of carbon cluster and induction by catalyst structure. This finding can help to build the comprehensive theory of nanotube growth and offers a prospect for chirality-preferential synthesis of carbon nanotubes by the exploitation of liquid catalyst droplets.

Chiral filtration-induced spin/valley polarization in silicene line defects

Science.gov (United States)

Ren, Chongdan; Zhou, Benhu; Sun, Minglei; Wang, Sake; Li, Yunfang; Tian, Hongyu; Lu, Weitao

2018-06-01

The spin/valley polarization in silicene with extended line defects is investigated according to the chiral filtration mechanism. It is shown that the inner-built quantum Hall pseudo-edge states with identical chirality can serve as a chiral filter with a weak magnetic field and that the transmission process is restrained/strengthened for chiral states with reversed/identical chirality. With two parallel line defects, which act as natural chiral filtration, the filter effect is greatly enhanced, and 100% spin/valley polarization can be achieved.

Physics of chiral symmetry breaking

International Nuclear Information System (INIS)

Shuryak, E.V.

1991-01-01

This subsection of the 'Modeling QCD' Workshop has included five talks. E. Shuryak spoke on 'Recent Progress in Understanding Chiral Symmetry Breaking'; below it is split into two parts: (i) a mini-review of the field and (ii) a brief presentation of the status of the theory of interacting instantons. The next sections correspond to the following talks: (iii) K. Goeke et al., 'Chiral Restoration and Medium Corrections to Nucleon in the NJL Model'; (iv) M. Takizawa and K. Kubodera, 'Study of Meson Properties and Quark Condensates in the NJL Model with Instanton Effects'; (v) G. Klein and A. G. Williams, 'Dynamical Chiral Symmetry Breaking in Dual QCD'; and (vi) R. D. Ball, 'Skyrmions and Baryons.' (orig.)

Cell chirality: emergence of asymmetry from cell culture.

Science.gov (United States)

Wan, Leo Q; Chin, Amanda S; Worley, Kathryn E; Ray, Poulomi

2016-12-19

Increasing evidence suggests that intrinsic cell chirality significantly contributes to the left-right (LR) asymmetry in embryonic development, which is a well-conserved characteristic of living organisms. With animal embryos, several theories have been established, but there are still controversies regarding mechanisms associated with embryonic LR symmetry breaking and the formation of asymmetric internal organs. Recently, in vitro systems have been developed to determine cell chirality and to recapitulate multicellular chiral morphogenesis on a chip. These studies demonstrate that chirality is indeed a universal property of the cell that can be observed with well-controlled experiments such as micropatterning. In this paper, we discuss the possible benefits of these in vitro systems to research in LR asymmetry, categorize available platforms for single-cell chirality and multicellular chiral morphogenesis, and review mathematical models used for in vitro cell chirality and its applications in in vivo embryonic development. These recent developments enable the interrogation of the intracellular machinery in LR axis establishment and accelerate research in birth defects in laterality.This article is part of the themed issue 'Provocative questions in left-right asymmetry'. © 2016 The Author(s).

Massive states in chiral perturbation theory

Energy Technology Data Exchange (ETDEWEB)

Mallik, S [Saha Inst. of Nuclear Physics, Calcutta (India)

1995-08-01

It is shown that the chiral nonanalytic terms generated by {Delta}{sub 33} resonance in the nucleon self-energy is reproduced in chiral perturbation theory by perturbing appropriate local operators contained in the pion-nucleon effective Lagrangian itself. (orig.)

Enantiomeric Profiling of Chiral Pharmacologically Active Compounds in the Environment with the Usage of Chiral Liquid Chromatography 
Coupled with Tandem Mass Spectrometry

Science.gov (United States)

Camacho-Muñoz, Dolores; Petrie, Bruce; Castrignanò, Erika; Kasprzyk-Hordern, Barbara

2016-01-01

The issue of drug chirality is attracting increasing attention among the scientific community. The phenomenon of chirality has been overlooked in environmental research (environmental occurrence, fate and toxicity) despite the great impact that chiral pharmacologically active compounds (cPACs) can provoke on ecosystems. The aim of this paper is to introduce the topic of chirality and its implications in environmental contamination. Special attention has been paid to the most recent advances in chiral analysis based on liquid chromatography coupled with mass spectrometry and the most popular protein based chiral stationary phases. Several groups of cPACs of environmental relevance, such as illicit drugs, human and veterinary medicines were discussed. The increase in the number of papers published in the area of chiral environmental analysis indicates that researchers are actively pursuing new opportunities to provide better understanding of environmental impacts resulting from the enantiomerism of cPACs. PMID:27713682

Topological valley-chiral edge states of Lamb waves in elastic thin plates

Science.gov (United States)

Wang, Jian; Mei, Jun

2018-05-01

We investigate the nontrivial topology of the band structure of Lamb waves in a thin phononic crystal plate. When inversion symmetry is broken, a valley pseudospin degree of freedom is formed around K and K‧ valleys for the A0 Lamb mode, which is decoupled from the S0 and SH0 modes in the low-frequency regime. Chiral edge states are explicitly demonstrated, which are immune to defects and exhibit unidirectional transport behaviors when intervalley scattering is weak. The quantum valley Hall effect is thus simulated in a simple way in the context of Lamb waves.

Chiral Plasmonic Nanostructures Fabricated by Circularly Polarized Light.

Science.gov (United States)

Saito, Koichiro; Tatsuma, Tetsu

2018-05-09

The chirality of materials results in a wide variety of advanced technologies including image display, data storage, light management including negative refraction, and enantioselective catalysis and sensing. Here, we introduce chirality to plasmonic nanostructures by using circularly polarized light as the sole chiral source for the first time. Gold nanocuboids as precursors on a semiconductor were irradiated with circularly polarized light to localize electric fields at specific corners of the cuboids depending on the handedness of light and deposited dielectric moieties as electron oscillation boosters by the localized electric field. Thus, plasmonic nanostructures with high chirality were developed. The present bottom-up method would allow the large-scale and cost-effective fabrication of chiral materials and further applications to functional materials and devices.

Positional stability experiment and analysis of elongated plasmas in Doublet III

International Nuclear Information System (INIS)

Yokomizo, Hideaki

1984-04-01

Control systems of the plasma position and shape on Doublet III are explained and experimental results of vertical stability of elongated plasmas are reviewed. Observed results of the vertical instability are qualitatively compared with the predictions from the simplified model and quantitatively compared with the numerical calculations based on a more realistic model. Experiments are in reasonable agreement with the theoretical analyses. (author)

Spin-Selective Transmission and Devisable Chirality in Two-Layer Metasurfaces.

Science.gov (United States)

Li, Zhancheng; Liu, Wenwei; Cheng, Hua; Chen, Shuqi; Tian, Jianguo

2017-08-15

Chirality is a nearly ubiquitous natural phenomenon. Its minute presence in most naturally occurring materials makes it incredibly difficult to detect. Recent advances in metasurfaces indicate that they exhibit devisable chirality in novel forms; this finding offers an effective opening for studying chirality and its features in such nanostructures. These metasurfaces display vast possibilities for highly sensitive chirality discrimination in biological and chemical systems. Here, we show that two-layer metasurfaces based on twisted nanorods can generate giant spin-selective transmission and support engineered chirality in the near-infrared region. Two designed metasurfaces with opposite spin-selective transmission are proposed for treatment as enantiomers and can be used widely for spin selection and enhanced chiral sensing. Specifically, we demonstrate that the chirality in these proposed metasurfaces can be adjusted effectively by simply changing the orientation angle between the twisted nanorods. Our results offer simple and straightforward rules for chirality engineering in metasurfaces and suggest intriguing possibilities for the applications of such metasurfaces in spin optics and chiral sensing.

Non-perturbative chiral corrections for lattice QCD

International Nuclear Information System (INIS)

Thomas, A.W.; Leinweber, D.B.; Lu, D.H.

2002-01-01

We explore the chiral aspects of extrapolation of observables calculated within lattice QCD, using the nucleon magnetic moments as an example. Our analysis shows that the biggest effects of chiral dynamics occur for quark masses corresponding to a pion mass below 600 MeV. In this limited range chiral perturbation theory is not rapidly convergent, but we can develop some understanding of the behaviour through chiral quark models. This model dependent analysis leads us to a simple Pade approximant which builds in both the limits m π → 0 and m π → ∞ correctly and permits a consistent, model independent extrapolation to the physical pion mass which should be extremely reliable. (author)

Modification of the twist angle in chiral nematic polymer films by photoisomerization of the chiral dopant

NARCIS (Netherlands)

Witte, van de P.; Neuteboom, E.E.; Brehmer, M.; Lub, Johan

1999-01-01

A method for the production of polarization sensitive recordings in liquid crystalline polymers is presented. The system is based on local modification of the twist angle of chiral nematic polymer films. The twist angle of the polymer film is varied by modifying the chemical structure of the chiral

DEVELOPMENT AND REGISTRATION OF CHIRAL DRUGS

NARCIS (Netherlands)

WITTE, DT; ENSING, K; FRANKE, JP; DEZEEUW, RA

1993-01-01

In this review we describe the impact of chirality on drug development and registration in the United States, Japan and the European Community. Enantiomers may have differences in their pharmacological profiles, and, therefore, chiral drugs ask for special analytical and pharmacological attention

LINEARLY POLARIZED PROBES OF SURFACE CHIRALITY

NARCIS (Netherlands)

VERBIEST, T; KAURANEN, M; MAKI, JJ; TEERENSTRA, MN; SCHOUTEN, AJ; NOLTE, RJM; PERSOONS, A

1995-01-01

We present a new nonlinear optical technique to study surface chirality. We demonstrate experimentally that the efficiency of second-harmonic generation from isotropic chiral surfaces is different for excitation with fundamental light that is +45 degrees and -45 degrees linearly polarized with

Chirality Relay in 2,2'-Substituted 1,1'-Binaphthyl: Access to Propeller Chirality of the Tricoordinate Boron Center.

Science.gov (United States)

Wang, Chen; Sun, Zuo-Bang; Xu, Qing-Wen; Zhao, Cui-Hua

2016-11-14

It is a challenging issue to achieve propeller chirality for triarylboranes owing to the low transition barrier between the P and M forms of the boron center. Herein, we report a new strategy to achieve propeller chirality of triarylboranes. It was found that the chirality relay from axially chiral 1,1'-binaphthyl to propeller chirality of the trivalent boron center can be realized when a Me 2 N and a Mes 2 B group (Mes=mesityl) are introduced at the 2,2'-positions of the 1,1'-binaphthyl skeleton (BN-BNaph) owing to the strong π-π interaction between the Me 2 N-bonded naphthyl ring and the phenyl ring of one adjacent Mes group, which not only exerts great steric hindrance on the rotation of the two Mes groups but also gives unequal stability to the two configurations of the boron center for a given configuration of the binaphthyl moiety. The stereostructures of the boron center were fully characterized through 1 H NMR spectroscopy, X-ray crystal analyses, and theoretical calculations. Detailed comparisons with the analog BN-Ph-BNaph, in which the Mes 2 B group is separated from 1,1'-binaphthyl by a para-phenylene spacer, confirmed the essential role of π-π interaction for the successful chirality relay in BN-BNaph. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photon-Assisted Resonant Chiral Tunneling Through a Bilayer Graphene Barrier

Directory of Open Access Journals (Sweden)

Phillips A. H.

2011-01-01

Full Text Available The electronic transport property of a bilayer graphene is investigated under the effect of an electromagnetic field. We deduce an expression for the conductance by solving the Dirac equation. This conductance depends on the barrier height for graphene and the energy of the induced photons. A resonance oscillatory behavior of the conductance is observed. These oscillations are strongly depends on the barrier height for chiral tunneling through graphene. This oscillatory behavior might be due to the interference of different central band and sidebands of graphene states. The present investigation is very important for the application of bilayer graphene in photodetector devices, for example, far-infrared photodevices and ultrafast lasers.

The three dimensional dual of 4D chirality

International Nuclear Information System (INIS)

Porrati, M.; Girardello, L.

2009-01-01

Chiral gauge theories can be defined in four-dimensional Anti de Sitter space, but AdS boundary conditions explicitly break the chiral symmetry in a specific, well defined manner, which in turns results in an anomalous Ward identity. When the 4D theory admits a dual description in terms of a 3D CFT, the 3D dual of the broken chiral symmetry is a certain double-trace deformation of the CFT, which produces the same anomalous chiral Ward identities that obtains in the 4D bulk theory.

Cell chirality: its origin and roles in left-right asymmetric development.

Science.gov (United States)

Inaki, Mikiko; Liu, Jingyang; Matsuno, Kenji

2016-12-19

An item is chiral if it cannot be superimposed on its mirror image. Most biological molecules are chiral. The homochirality of amino acids ensures that proteins are chiral, which is essential for their functions. Chirality also occurs at the whole-cell level, which was first studied mostly in ciliates, single-celled protozoans. Ciliates show chirality in their cortical structures, which is not determined by genetics, but by 'cortical inheritance'. These studies suggested that molecular chirality directs whole-cell chirality. Intriguingly, chirality in cellular structures and functions is also found in metazoans. In Drosophila, intrinsic cell chirality is observed in various left-right (LR) asymmetric tissues, and appears to be responsible for their LR asymmetric morphogenesis. In other invertebrates, such as snails and Caenorhabditis elegans, blastomere chirality is responsible for subsequent LR asymmetric development. Various cultured cells of vertebrates also show intrinsic chirality in their cellular behaviours and intracellular structural dynamics. Thus, cell chirality may be a general property of eukaryotic cells. In Drosophila, cell chirality drives the LR asymmetric development of individual organs, without establishing the LR axis of the whole embryo. Considering that organ-intrinsic LR asymmetry is also reported in vertebrates, this mechanism may contribute to LR asymmetric development across phyla.This article is part of the themed issue 'Provocative questions in left-right asymmetry'. © 2016 The Authors.

Cell chirality: its origin and roles in left–right asymmetric development

Science.gov (United States)

Inaki, Mikiko; Liu, Jingyang

2016-01-01

An item is chiral if it cannot be superimposed on its mirror image. Most biological molecules are chiral. The homochirality of amino acids ensures that proteins are chiral, which is essential for their functions. Chirality also occurs at the whole-cell level, which was first studied mostly in ciliates, single-celled protozoans. Ciliates show chirality in their cortical structures, which is not determined by genetics, but by ‘cortical inheritance’. These studies suggested that molecular chirality directs whole-cell chirality. Intriguingly, chirality in cellular structures and functions is also found in metazoans. In Drosophila, intrinsic cell chirality is observed in various left–right (LR) asymmetric tissues, and appears to be responsible for their LR asymmetric morphogenesis. In other invertebrates, such as snails and Caenorhabditis elegans, blastomere chirality is responsible for subsequent LR asymmetric development. Various cultured cells of vertebrates also show intrinsic chirality in their cellular behaviours and intracellular structural dynamics. Thus, cell chirality may be a general property of eukaryotic cells. In Drosophila, cell chirality drives the LR asymmetric development of individual organs, without establishing the LR axis of the whole embryo. Considering that organ-intrinsic LR asymmetry is also reported in vertebrates, this mechanism may contribute to LR asymmetric development across phyla. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’. PMID:27821533

Asymmetric chiral colour

International Nuclear Information System (INIS)

Cuypers, F.

1990-01-01

Chiral colour is considered in a general framework where the coupling constants associated with each SU(3) component are allowed to be different. To reproduce QCD at low energy, gluons and axigluons cannot then be maximally mixed. Present data form e + e - colliders contrains the axigluon mass to values between 50 GeV and 375 GeV whilst the mixing angle is bounded by 13deg and 45deg. The lower limit of the axigluon mass is a definite bound at 90% C.L., whereas the upper limit only applies if chiral colour is to explain the anomalously high rates of hadron production at TRISTAN. (orig.)

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.

Chiral interaction and biomolecular evolution

International Nuclear Information System (INIS)

Gilat, G.

1992-01-01

Recent developments in the concept of chiral interaction open now new options and dynamical possibilities for biomolecules which have so far been overlooked. A few of these possibilities are mentioned, such as the control mechanism of enzymatic activity and the role played by non-ergodicity in evolutionary processes. It is shown that chiral interaction, being a surface phenomenon, does not obey Barron's symmetry constraints, which are suitable for force fields present in bulk interactions. In particular, the situation at the ocean-air surface in the prebiotic era is described, as well as the possible role played by chiral interaction in conjunction with the terrestrial magnetic field normal to the ocean surface, which could have lead to a process of deracernization at the ocean-air interface. (author)

Fusion rules of chiral algebras

International Nuclear Information System (INIS)

Gaberdiel, M.

1994-01-01

Recently we showed that for the case of the WZW and the minimal models fusion can be understood as a certain ring-like tensor product of the symmetry algebra. In this paper we generalize this analysis to arbitrary chiral algebras. We define the tensor product of conformal field theory in the general case and prove that it is associative and symmetric up to equivalence. We also determine explicitly the action of the chiral algebra on this tensor product. In the second part of the paper we demonstrate that this framework provides a powerful tool for calculating restrictions for the fusion rules of chiral algebras. We exhibit this for the case of the W 3 algebra and the N=1 and N=2 NS superconformal algebras. (orig.)

Probing chirality with a femtosecond reaction microscope

Directory of Open Access Journals (Sweden)

Janssen M. H. M.

2013-03-01

Full Text Available Detection of molecular chirality with high sensitivity and selectivity is important for many analytical and practical applications. Photoionization has emerged as a very sensitive probe of chirality in molecules. We show here that a table top setup with a femtosecond laser and a single imaging detector for both photoelectrons and photoions enables detection of chirality up to 3 orders of magnitude better than the existing conventional absorption based techniques.

The role of resonances in chiral perturbation theory

International Nuclear Information System (INIS)

Ecker, G.; Rafael, E. de

1988-09-01

The strong interactions of low-lying meson resonances (spin ≤ 1) with the octet of pseudoscalar mesons (π,Κ,η) are considered to lowest order in the derivative expansion of chiral SU(3). The resonance contributions to the coupling constants of the O(p 4 ) effective chiral lagrangian involving pseudoscalar fields only are determined. These low-energy coupling constants are found to be dominated by the resonance contributions. Although we do not treat the vector and axial-vector mesons as gauge bosons of local chiral symmetry, vector meson dominance emerges as a prominent result of our analysis. As a further application of chiral resonance couplings, we calculate the electromagnetic pion mass difference to lowest order in chiral perturbation theory with explicit resonance fields. 29 refs., 2 figs., 5 tabs. (Author)

Can the chirality of the ISM be measured

Science.gov (United States)

Pendleton, Y.; Sandford, S. A.; Werner, Michael W.; Lauer, J.; Chang, Sherwood

1990-01-01

Many moderately complex carbon-based molecules of the type associated with biological systems can exist in one of two mirror-image forms (left-handed and right-handed), which can be distinguished on the basis of their influence on the state of polarization of a light beam. Both forms are possible in nature; yet in living organisms it is invariably the rule that one of these two species predominates. This gives rise to a net chirality. One possible explanation for the net chirality is that the early earth was somehow seeded from the ISM with an excess of chiral organic compounds which led to the development of life forms which are based on left-handed amino acids and right-handed sugars. Molecular spectroscopy of the interstellar medium (ISM) has revealed a complex variety of molecular species similar to those thought to have been available in the oceans and atmospheres of the earth at the time life formed. The detection of such molecules demonstrates the generality of the chemical processes occurring in both environments. If this generality extends to the processes which produce chirality, it may be possible to detect a net chirality in the ISM. This is of particular interest because determining whether or not net chirality exists elsewhere in the universe is an essential aspect of understanding how life developed on earth and how widely distributed it might be. Researchers report preliminary results of a feasibility study to determine whether or not a net chirality in the ISM can be measured. If laboratory results identify candidate chiral molecules that might exist in the ISM, the next step in this feasibility study will be to estimate the detectability of the chiral signature in astrophysical environments.

Can the chirality of the ISM be measured

International Nuclear Information System (INIS)

Pendleton, Y.; Sandford, S.A.; Werner, M.W.; Lauer, J.; Chang, S.

1990-01-01

Many moderately complex carbon-based molecules of the type associated with biological systems can exist in one of two mirror-image forms (left-handed and right-handed), which can be distinguished on the basis of their influence on the state of polarization of a light beam. Both forms are possible in nature; yet in living organisms it is invariably the rule that one of these two species predominates. This gives rise to a net chirality. One possible explanation for the net chirality is that the early earth was somehow seeded from the ISM with an excess of chiral organic compounds which led to the development of life forms which are based on left-handed amino acids and right-handed sugars. Molecular spectroscopy of the interstellar medium (ISM) has revealed a complex variety of molecular species similar to those thought to have been available in the oceans and atmospheres of the earth at the time life formed. The detection of such molecules demonstrates the generality of the chemical processes occurring in both environments. If this generality extends to the processes which produce chirality, it may be possible to detect a net chirality in the ISM. This is of particular interest because determining whether or not net chirality exists elsewhere in the universe is an essential aspect of understanding how life developed on earth and how widely distributed it might be. Researchers report preliminary results of a feasibility study to determine whether or not a net chirality in the ISM can be measured. If laboratory results identify candidate chiral molecules that might exist in the ISM, the next step in this feasibility study will be to estimate the detectability of the chiral signature in astrophysical environments

Intrinsic Chirality and Prochirality at Air/R-(+)- and S-(-)-Limonene Interfaces: Spectral Signatures with Interference Chiral Sum-Frequency Generation Vibrational Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Fu, Li; Zhang, Yun; Wei, Zhehao; Wang, Hongfei

2014-06-04

We report in this work detailed measurements on the chiral and achiral sum-frequency vibrational spectra in the C-H stretching vibration region (2800-3050cm-1) of the air/liquid interfaces of R-limonene and S-limonene, using the recently developed high-resolution broadband sum-frequency generation vibrational spectroscopy (HR-BB-SFG-VS). The achiral SFG spectra of R-limonene and S-limonene, as well as the equal amount (50/50) racemic mixture show that the enantiomers are with the same interfacial orientations. The interference chiral SFG spectra of the limonene enantiomers exhibit spectral signature from chiral response of the Cα-H stretching mode, and spectral signature from prochiral response of the CH2 asymmetric stretching mode, respectively. The chiral spectral feature of the Cα-H stretching mode changes sign from R-limonene to S-limonene, and disappears for the 50/50 racemic mixture. While the prochiral spectral feature of the CH2 asymmetric stretching mode is the same for R-limonene and S-limonene, and also surprisingly remains the same for the 50/50 racemic mixture. These results provided detail information in understanding the structure and chirality of molecular interfaces, and demonstrated the sensitivity and potential of SFG-VS as unique spectroscopic tool for chirality characterization and chiral recognition at the molecular interface.

Chiral metamaterials: from optical activity and negative refractive index to asymmetric transmission

International Nuclear Information System (INIS)

Li, Zhaofeng; Mutlu, Mehmet; Ozbay, Ekmel

2013-01-01

We summarize the progress in the development and application of chiral metamaterials. After a brief review of the salient features of chiral metamaterials, such as giant optical activity, circular dichroism, and negative refractive index, the common method for the retrieval of effective parameters for chiral metamaterials is surveyed. Then, we introduce some typical chiral structures, e.g., chiral metamaterial consisting of split ring resonators, complementary chiral metamaterial, and composite chiral metamaterial, on the basis of the studies of the authors’ group. The coupling effect during the construction of bulk chiral metamaterials is mentioned and discussed. We introduce the application of bianisotropic chiral structures in the field of asymmetric transmission. Finally, we mention a few directions for future research on chiral metamaterials. (review article)

The Features of Moessbauer Spectra of Hemoglobins: Approximation by Superposition of Quadrupole Doublets or by Quadrupole Splitting Distribution?

International Nuclear Information System (INIS)

Oshtrakh, M. I.; Semionkin, V. A.

2004-01-01

Moessbauer spectra of hemoglobins have some features in the range of liquid nitrogen temperature: a non-Lorentzian asymmetric line shape for oxyhemoglobins and symmetric Lorentzian line shape for deoxyhemoglobins. A comparison of the approximation of the hemoglobin Moessbauer spectra by a superposition of two quadrupole doublets and by a distribution of the quadrupole splitting demonstrates that a superposition of two quadrupole doublets is more reliable and may reflect the non-equivalent iron electronic structure and the stereochemistry in the α- and β-subunits of hemoglobin tetramers.

Quark matter in a chiral chromodielectric model

International Nuclear Information System (INIS)

Broniowski, W.; Kutschera, M.; Cibej, M.; Rosina, M.

1989-03-01

Zero and finite temperature quark matter is studied in a chiral chromodielectric model with quark, meson and chromodielectric degrees of freedom. Mean field approximation is used. Two cases are considered: two-flavor and three-flavor quark matter. It is found that at sufficiently low densities and temperatures the system is in a chirally broken phase, with quarks acquiring effective masses of the order of 100 MeV. At higher densities and temperatures a chiral phase transition occurs and the quarks become massless. A comparison to traditional nuclear physics suggests that the chirally broken phase with massive quark gas may be the ground state of matter at densities of the order of a few nuclear saturation densities. 24 refs., 5 figs. (author)

Laminar and Turbulent Dynamos in Chiral Magnetohydrodynamics. II. Simulations

Science.gov (United States)

Schober, Jennifer; Rogachevskii, Igor; Brandenburg, Axel; Boyarsky, Alexey; Fröhlich, Jürg; Ruchayskiy, Oleg; Kleeorin, Nathan

2018-05-01

Using direct numerical simulations (DNS), we study laminar and turbulent dynamos in chiral magnetohydrodynamics with an extended set of equations that accounts for an additional contribution to the electric current due to the chiral magnetic effect (CME). This quantum phenomenon originates from an asymmetry between left- and right-handed relativistic fermions in the presence of a magnetic field and gives rise to a chiral dynamo. We show that the magnetic field evolution proceeds in three stages: (1) a small-scale chiral dynamo instability, (2) production of chiral magnetically driven turbulence and excitation of a large-scale dynamo instability due to a new chiral effect (α μ effect), and (3) saturation of magnetic helicity and magnetic field growth controlled by a conservation law for the total chirality. The α μ effect becomes dominant at large fluid and magnetic Reynolds numbers and is not related to kinetic helicity. The growth rate of the large-scale magnetic field and its characteristic scale measured in the numerical simulations agree well with theoretical predictions based on mean-field theory. The previously discussed two-stage chiral magnetic scenario did not include stage (2), during which the characteristic scale of magnetic field variations can increase by many orders of magnitude. Based on the findings from numerical simulations, the relevance of the CME and the chiral effects revealed in the relativistic plasma of the early universe and of proto-neutron stars are discussed.

Chiral Recognition by Fluorescence: One Measurement for Two Parameters

Directory of Open Access Journals (Sweden)

Shanshan Yu

2014-01-01

Full Text Available This outlook describes two strategies to simultaneously determine the enantiomeric composition and concentration of a chiral substrate by a single fluorescent measurement. One strategy utilizes a pseudoenantiomeric sensor pair that is composed of a 1,1′-bi-2-naphthol-based amino alcohol and a partially hydrogenated 1,1′-bi-2-naphthol-based amino alcohol. These two molecules have the opposite chiral configuration with fluorescent enhancement at two different emitting wavelengths when treated with the enantiomers of mandelic acid. Using the sum and difference of the fluorescent intensity at the two wavelengths allows simultaneous determination of both concentration and enantiomeric composition of the chiral acid. The other strategy employs a 1,1′-bi-2-naphthol-based trifluoromethyl ketone that exhibits fluorescent enhancement at two emission wavelengths upon interaction with a chiral diamine. One emission responds mostly to the concentration of the chiral diamine and the ratio of the two emissions depends on the chiral configuration of the enantiomer but independent of the concentration, allowing both the concentration and enantiomeric composition of the chiral diamine to be simultaneously determined. These strategies would significantly simplify the practical application of the enantioselective fluorescent sensors in high-throughput chiral assay.

From cosmic chirality to protein structure: Lord Kelvin's legacy.

Science.gov (United States)

Barron, Laurence D

2012-11-01

A selection of my work on chirality is sketched in two distinct parts of this lecture. Symmetry and Chirality explains how the discrete symmetries of parity P, time reversal T, and charge conjugation C may be used to characterize the properties of chiral systems. The concepts of true chirality (time-invariant enantiomorphism) and false chirality (time-noninvariant enantiomorphism) that emerge provide an extension of Lord Kelvin's original definition of chirality to situations where motion is an essential ingredient thereby clarifying, inter alia, the nature of physical influences able to induce absolute enantioselection. Consideration of symmetry violations reveals that strict enantiomers (exactly degenerate) are interconverted by the combined CP operation. Raman optical activity surveys work, from first observation to current applications, on a new chiroptical spectroscopy that measures vibrational optical activity via Raman scattering of circularly polarized light. Raman optical activity provides incisive information ranging from absolute configuration and complete solution structure of smaller chiral molecules and oligomers to protein and nucleic acid structure of intact viruses. Copyright © 2012 Wiley Periodicals, Inc., A Wiley Company.

Rationalization of chirality induction and inversion in a zinc trisporphyrinate by a chiral monoalcohol.

Science.gov (United States)

Li, Li; Hu, Chuanjiang; Shi, Bo; Wang, Yong

2016-05-10

A new host-guest system is formed between a benzene tricarboxamide linked zinc trisporphyrinate and a chiral monoalcohol (1-phenylethylalcohol). CD spectra show the chirality induction and inversion processes, which are controlled by the corresponding 1 : 1 and 1 : 2 coordination complexes. The binding constants calculated by UV-vis and CD spectral data are much larger than that for [Zn(TPP)] (TPP = tetraphenylporphyrin). The crystallographic structure of the host-guest complex reveals that multiple intramolecular hydrogen bonds and π-π interactions could contribute to its high binding affinity to 1-phenylethylalcohol. The DFT calculations suggest that the spatial orientations of porphyrin moieties change from the 1 : 1 complex to the 1 : 2 complex. The chirality induction and inversion processes are rationalized by the summation of pairwise interactions among multichromophores according to pairwise additivity.

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

The Doublet III neutral beam injector cryosystem

International Nuclear Information System (INIS)

Langhorn, A.R.

1984-01-01

This chapter describes neutral beam injection into the Doublet III tokamak for plasma heating experiments. Cryopanels employed in the beamline vacuum pumping system are force flow cooled to 3.8 K by a closed loop refrigeration system. Topics considered include beamline description, cryosystem description, system characteristics, and operational history. Evaluation of the first beamline was carried out using a 25 L/h liquefier and a unique reliquefaction heat exchanger to permit subatmospheric operation and panel flow rates of 140 L/h. The system was upgraded for three beamline operation by substitution of a 100 L/h liquefier and more cryogen storage capacity. It is concluded that the cryosystem gives stable operation of three beamline cryopanel arrays with little operator intervention

Topological magnon bands in ferromagnetic star lattice

International Nuclear Information System (INIS)

Owerre, S A

2017-01-01

The experimental observation of topological magnon bands and thermal Hall effect in a kagomé lattice ferromagnet Cu(1–3, bdc) has inspired the search for topological magnon effects in various insulating ferromagnets that lack an inversion center allowing a Dzyaloshinskii–Moriya (DM) spin–orbit interaction. The star lattice (also known as the decorated honeycomb lattice) ferromagnet is an ideal candidate for this purpose because it is a variant of the kagomé lattice with additional links that connect the up-pointing and down-pointing triangles. This gives rise to twice the unit cell of the kagomé lattice, and hence more interesting topological magnon effects. In particular, the triangular bridges on the star lattice can be coupled either ferromagnetically or antiferromagnetically which is not possible on the kagomé lattice ferromagnets. Here, we study DM-induced topological magnon bands, chiral edge modes, and thermal magnon Hall effect on the star lattice ferromagnet in different parameter regimes. The star lattice can also be visualized as the parent material from which topological magnon bands can be realized for the kagomé and honeycomb lattices in some limiting cases. (paper)

Topological magnon bands in ferromagnetic star lattice.

Science.gov (United States)

Owerre, S A

2017-05-10

The experimental observation of topological magnon bands and thermal Hall effect in a kagomé lattice ferromagnet Cu(1-3, bdc) has inspired the search for topological magnon effects in various insulating ferromagnets that lack an inversion center allowing a Dzyaloshinskii-Moriya (DM) spin-orbit interaction. The star lattice (also known as the decorated honeycomb lattice) ferromagnet is an ideal candidate for this purpose because it is a variant of the kagomé lattice with additional links that connect the up-pointing and down-pointing triangles. This gives rise to twice the unit cell of the kagomé lattice, and hence more interesting topological magnon effects. In particular, the triangular bridges on the star lattice can be coupled either ferromagnetically or antiferromagnetically which is not possible on the kagomé lattice ferromagnets. Here, we study DM-induced topological magnon bands, chiral edge modes, and thermal magnon Hall effect on the star lattice ferromagnet in different parameter regimes. The star lattice can also be visualized as the parent material from which topological magnon bands can be realized for the kagomé and honeycomb lattices in some limiting cases.

A Review on Chiral Chromatography and its Application to the ...

African Journals Online (AJOL)

MoZarD

amounts of material and is for measuring the relative proportions of ... the stationary phase must themselves be made chiral, giving differing ... electrophoretic medium that change it to chiral mobile phase (Eliel, et ... column containing a chiral stationary phase is also called a chiral ... densitometry, and a TLC method for the.

Chiral thermodynamics of nuclear matter

International Nuclear Information System (INIS)

Fiorilla, Salvatore

2012-01-01

The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.

Chiral thermodynamics of nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Fiorilla, Salvatore

2012-10-23

The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.

Re-derived overclosure bound for the inert doublet model

Science.gov (United States)

Biondini, S.; Laine, M.

2017-08-01

We apply a formalism accounting for thermal effects (such as modified Sommerfeld effect; Salpeter correction; decohering scatterings; dissociation of bound states), to one of the simplest WIMP-like dark matter models, associated with an "inert" Higgs doublet. A broad temperature range T ˜ M/20 . . . M/104 is considered, stressing the importance and less-understood nature of late annihilation stages. Even though only weak interactions play a role, we find that resummed real and virtual corrections increase the tree-level overclosure bound by 1 . . . 18%, depending on quartic couplings and mass splittings.

Inexpensive chirality on the lattice

International Nuclear Information System (INIS)

Kamleh, W.; Williams, A.G.; Adams, D.

2000-01-01

Full text: Implementing lattice fermions that resemble as closely as possible continuum fermions is one of the main goals of the theoretical physics community. Aside from a lack of infinitely powerful computers, one of the main impediments to this is the Nielsen-Ninomiya No-Go theorem for chirality on the lattice. One of the consequences of this theorem is that exact chiral symmetry and a lack of fermion doublers cannot be simultaneously satisfied for fermions on the lattice. In the commonly used Wilson fermion formulation, chiral symmetry is explicitly sacrificed on the lattice to avoid fermion doubling. Recently, an alternative has come forward, namely, the Ginsparg-Wilson relation and one of its solutions, the Overlap fermion. The Ginsparg-Wilson relation is a statement of lattice-deformed chirality. The Overlap-Dirac operator is a member of the family of solutions of the Ginsparg-Wilson relation. In recent times, Overlap fermions have been of great interest to the community due to their excellent chiral properties. However, they are significantly more expensive to implement than Wilson fermions. This expense is primarily due to the fact that the Overlap implementation requires an evaluation of the sign function for the Wilson-Dirac operator. The sign function is approximated by a high order rational polynomial function, but this approximation is poor close to the origin. The less near-zero modes that the Wilson- Dirac operator possesses, the cheaper the Overlap operator will be to implement. A means of improving the eigenvalue properties of the Wilson-Dirac operator by the addition of a so-called 'Clover' term is put forward. Numerical results are given that demonstrate this improvement. The Nielsen-Ninomiya no-go theorem and chirality on the lattice are reviewed. The general form of solutions of the Ginsparg-Wilson relation are given, and the Overlap solution is discussed. Properties of the Overlap-Dirac operator are given, including locality and analytic

Patterns of symmetry breaking in chiral QCD

Science.gov (United States)

Bolognesi, Stefano; Konishi, Kenichi; Shifman, Mikhail

2018-05-01

We consider S U (N ) Yang-Mills theory with massless chiral fermions in a complex representation of the gauge group. The main emphasis is on the so-called hybrid ψ χ η model. The possible patterns of realization of the continuous chiral flavor symmetry are discussed. We argue that the chiral symmetry is broken in conjunction with a dynamical Higgsing of the gauge group (complete or partial) by bifermion condensates. As a result a color-flavor locked symmetry is preserved. The 't Hooft anomaly matching proceeds via saturation of triangles by massless composite fermions or, in a mixed mode, i.e. also by the "weakly" coupled fermions associated with dynamical Abelianization, supplemented by a number of Nambu-Goldstone mesons. Gauge-singlet condensates are of the multifermion type and, though it cannot be excluded, the chiral symmetry realization via such gauge invariant condensates is more contrived (requires a number of four-fermion condensates simultaneously and, even so, problems remain) and less plausible. We conclude that in the model at hand, chiral flavor symmetry implies dynamical Higgsing by bifermion condensates.

Chiral superfluidity of the quark-gluon plasma

International Nuclear Information System (INIS)

Kalaydzhyan, Tigran

2012-08-01

In this paper we argue that the strongly coupled quark-gluon plasma can be considered as a chiral superfluid. The ''normal'' component of the fluid is the thermalized matter in common sense, while the ''superfluid'' part consists of long wavelength (chiral) fermionic states moving independently. We use several nonperturbative techniques to demonstrate that. First, we analyze the fermionic spectrum in the deconfinement phase (T c c ) using lattice (overlap) fermions and observe a gap between near-zero modes and the bulk of the spectrum. Second, we use the bosonization procedure with a finite cut-off and obtain a dynamical axion-like field out of the chiral fermionic modes. Third, we use relativistic hydrodynamics for macroscopic description of the effective theory obtained after the bosonization. Finally, solving the hydrodynamic equations in gradient expansion, we find that in the presence of external electromagnetic fields the motion of the ''superfluid'' component gives rise to the chiral magnetic, chiral electric and dipole wave effects. Latter two effects are specific for a two-component fluid, which provides us with crucial experimental tests of the model.

Resuscitation of the three-scalar doublet model with spontaneous CP violation

International Nuclear Information System (INIS)

Branco, G.C.; Buras, A.J.; Gerard, J.M.

1985-01-01

We show that the three-scalar doublet model with spontaneous CP violation and natural flavor conservation can be made consistent with the recent measurements of epsilon'/epsilon provided an interesting hierarchy among the vacuum expectation values present in the model is assumed. Simultaneously ΔM(Ksub(L)-Ksub(S)), the epsilon parameter and the electric dipole moment of the neutron are consistent with the experimental data. (orig.)

Chiral Drug Analysis in Forensic Chemistry: An Overview

Directory of Open Access Journals (Sweden)

Cláudia Ribeiro

2018-01-01

Full Text Available Many substances of forensic interest are chiral and available either as racemates or pure enantiomers. Application of chiral analysis in biological samples can be useful for the determination of legal or illicit drugs consumption or interpretation of unexpected toxicological effects. Chiral substances can also be found in environmental samples and revealed to be useful for determination of community drug usage (sewage epidemiology, identification of illicit drug manufacturing locations, illegal discharge of sewage and in environmental risk assessment. Thus, the purpose of this paper is to provide an overview of the application of chiral analysis in biological and environmental samples and their relevance in the forensic field. Most frequently analytical methods used to quantify the enantiomers are liquid and gas chromatography using both indirect, with enantiomerically pure derivatizing reagents, and direct methods recurring to chiral stationary phases.

Chiral recognition with enantioselective ion exchangers based on carbamoylated cinchonan derivatives as chiral selectors for the HPLC enantioseparation

International Nuclear Information System (INIS)

Laemmerhofer, M.

1996-11-01

The high-performance liquid chromatographic (HPLC) separation of enantiomers is preferentially performed using chiral stationary phases (CSPs). If the chiral auxiliary (selector, SO) contains charged or ionizable groups one gets ion exchanger type CSPs which may bind and retain oppositely charged analytes (selectands, SAs). We prepared anion exchanger type CSPs with various quinine and quinidine carbarnates as chiral SOs immobilized either on porous or non-porous silica. These CSPs are able to resolve the enantiomers of a wide spectrum of chiral carboxylic, sulfonic, phosphonic, phosphoric acids and of many other chiral acidic solutes (e.g. N-derivatized alpha-, beta- , gamma-amino acids as 2,4-dinitrophenyl, 3,5-dinitrobenzoyl, benzoyl, acetyl, formyl, t.-butoxycarbonyl, benzyloxycarbonyl, 9-fluorenylmethoxycarbonyl, dansyl amino acids and peptides, alpha-arylalkylcarboxylic acids as profens, alpha-aryloxyalkylcarboxylic acids, alpha-arylthioalkylcarboxylic acids and acidic drugs like etodolac, proglumide, acenocournarol, leucovorin, omeprazole, pantoprazole) employing buffered aqueous mobile phases or non-aqueous mobile phases with buffer dissolved in the organic solvent. The influence of mobile phase parameters and other experimental conditions on retention and enantioselectivity has been evaluated for isocratic and gradient elution techniques, aided by the commercial method development computer software DryLab. Several 'Quantitative Structure-Retention Relationships' (QSRR) have been derived, which allowed prediction of enantioselectivity of new analytes and moreover the optimization of the SO-structure. Spectroscopic investigations as H-NMR, FTIR of certain SO-SA-complexes have been exerted to unveil the mechanism of chiral recognition. (author)

Chirality and gravitational parity violation.

Science.gov (United States)

Bargueño, Pedro

2015-06-01

In this review, parity-violating gravitational potentials are presented as possible sources of both true and false chirality. In particular, whereas phenomenological long-range spin-dependent gravitational potentials contain both truly and falsely chiral terms, it is shown that there are models that extend general relativity including also coupling of fermionic degrees of freedom to gravity in the presence of torsion, which give place to short-range truly chiral interactions similar to that usually considered in molecular physics. Physical mechanisms which give place to gravitational parity violation together with the expected size of the effects and their experimental constraints are discussed. Finally, the possible role of parity-violating gravity in the origin of homochirality and a road map for future research works in quantum chemistry is presented. © 2015 Wiley Periodicals, Inc.