Bohm's theory versus dynamical reduction
International Nuclear Information System (INIS)
This essay begins with a comparison between Bohm's theory and the dynamical reduction program. While there are similarities (e.g., the preferred basis), there are also important differences (e.g., the type of nonlocality or of Lorentz invariance). In particular, it is made plausible that theories which exhibit parameter dependence effects cannot be ''genuinely Lorentz invariant''. For the two approaches under consideration, this analysis provides a comparison that can produce a richer understanding both of the pilot wave and of the dynamical reduction mechanism. (author). 33 refs, 1 fig
Kinetic Theory of the Presheath and the Bohm Criterion
Baalrud, S D; Hegna, C C
2013-01-01
A kinetic theory of the Bohm criterion is developed that is based on positive-exponent velocity moments of the plasma kinetic equation. This result is contrasted with the conventional kinetic Bohm criterion that is based on a v^{-1} moment of the Vlasov equation. The salient difference between the two results is that low velocity particles dominate in the conventional theory, but are essentially unimportant in the new theory. It is shown that the derivation of the conventional kinetic Bohm cr...
On superselection rules in Bohm-Bell theories
International Nuclear Information System (INIS)
The meaning of superselection rules in Bohm-Bell theories (i.e., quantum theories with particle trajectories) is different from that in orthodox quantum theory. More precisely, there are two concepts of superselection rule, a weak and a strong one. Weak superselection rules exist both in orthodox quantum theory and in Bohm-Bell theories and represent the conventional understanding of superselection rules. We introduce the concept of strong superselection rule, which does not exist in orthodox quantum theory. It relies on the clear ontology of Bohm-Bell theories and is a sharper and, in the Bohm-Bell context, more fundamental notion. A strong superselection rule for the observable G asserts that one can replace every state vector by a suitable statistical mixture of eigenvectors of G without changing the particle trajectories or their probabilities. A weak superselection rule asserts that every state vector is empirically indistinguishable from a suitable statistical mixture of eigenvectors of G. We establish conditions on G for both kinds of superselection. For comparison, we also consider both kinds of superselection in theories of spontaneous wavefunction collapse
Spectral and scattering theory for the Aharonov-Bohm operators
Pankrashkin, Konstantin; Richard, Serge
2011-01-01
We review the spectral and the scattering theory for the Aharonov-Bohm model on $\\mathbb{R}^2$. New formulae for the wave operators and for the scattering operator are presented. The asymptotics at high and at low energy of the scattering operator are computed.
Analogue Aharonov-Bohm effect in neo-Newtonian theory
Anacleto, M A; Brito, F A; Passos, E
2015-01-01
We address the issues of the scattering of massless planar scalar waves by an acoustic black hole in neo-Newtonian hydrodynamics. We then compute the differential cross section through the use of the partial wave approach in the neo-Newtonian theory which is a modification of the usual Newtonian theory that correctly incorporates the effects of pressure. We mainly show that the scattering of planar waves leads to a modified analogue Aharonov-Bohm effect due to a nontrivial response of the parameters defining the equation of state.
Analogue Aharonov-Bohm effect in neo-Newtonian theory
Anacleto, M. A.; Salako, I. G.; Brito, F. A.; Passos, E.
2015-12-01
We address the issues of the scattering of massless planar scalar waves by an acoustic black hole in neo-Newtonian hydrodynamics. We then compute the differential cross section through the use of the partial wave approach in the neo-Newtonian theory which is a modification of the usual Newtonian theory that correctly incorporates the effects of pressure. We mainly show that the scattering of planar waves leads to a modified analogue Aharonov-Bohm effect due to a nontrivial response of the parameters defining the equation of state.
Analogue Aharonov-Bohm effect in neo-Newtonian theory
Anacleto, M.A.(Departamento de Física, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraíba, Brazil); Salako, I. G.; Brito, F. A.; Passos, E.
2015-01-01
We address the issues of the scattering of massless planar scalar waves by an acoustic black hole in neo-Newtonian hydrodynamics. We then compute the differential cross section through the use of the partial wave approach in the neo-Newtonian theory which is a modification of the usual Newtonian theory that correctly incorporates the effects of pressure. We mainly show that the scattering of planar waves leads to a modified analogue Aharonov-Bohm effect due to a nontrivial response of the par...
Aharonov-Bohm Effect in Perturbation Theory.
Purcell, Kay M.; Henneberger, Walter C.
1978-01-01
The Aharonov-Bohn effect is obtained in first-order perturbation theory. It is shown that the effect occurs only when the initial state is a superposition of eigenstates of Lz corresponding to eigenvalues having opposite sign. (Author/GA)
Discrete Gauge Symmetry and Aharonov-Bohm Radiation in String Theory
Ookouchi, Yutaka
2013-01-01
We investigate cosmological constraints on phenomenological models with discrete gauge symmetries by discussing the radiation of standard model particles from Aharonov-Bohm strings. Using intersecting D-brane models in Type IIA string theory, we demonstrate that Aharonov-Bohm radiation, when combined with cosmological observations, imposes constraints on the compactification scales.
Discrete gauge symmetry and Aharonov-Bohm radiation in string theory
Energy Technology Data Exchange (ETDEWEB)
Ookouchi, Yutaka [Faculty of Arts and Science, Kyushu University, Fukuoka 819-0395 (Japan)
2014-01-10
We investigate cosmological constraints on phenomenological models with discrete gauge symmetries by discussing the radiation of standard model particles from Aharonov-Bohm strings. Using intersecting D-brane models in Type IIA string theory, we demonstrate that Aharonov-Bohm radiation, when combined with cosmological observations, imposes constraints on the compactification scales.
Discrete gauge symmetry and Aharonov-Bohm radiation in string theory
Yutaka Ookouchi
2014-01-01
We investigate cosmological constraints on phenomenological models with discrete gauge symmetries by discussing the radiation of standard model particles from Aharonov-Bohm strings. Using intersecting D-brane models in Type IIA string theory, we demonstrate that Aharonov-Bohm radiation, when combined with cosmological observations, imposes constraints on the compactification scales.
Discrete gauge symmetry and Aharonov-Bohm radiation in string theory
International Nuclear Information System (INIS)
We investigate cosmological constraints on phenomenological models with discrete gauge symmetries by discussing the radiation of standard model particles from Aharonov-Bohm strings. Using intersecting D-brane models in Type IIA string theory, we demonstrate that Aharonov-Bohm radiation, when combined with cosmological observations, imposes constraints on the compactification scales
Aharonov--Bohm Effect in 3D Abelian Higgs Theory
Chernodub, M. N.; Gubarev, F. V.; Polikarpov, M.I.
1996-01-01
We study a field--theoretical analogue of the Aharonov--Bohm effect in the 3D Abelian Higgs Model: the corresponding topological interaction is proportional to the linking number of the vortex and the particle world trajectories. We show that the Aharonov--Bohm effect gives rise to a nontrivial interaction of tested charged particles.
Particle Physics challenges to the Bohm Picture of Relativistic Quantum Field Theory
Miranda, Abel
2011-01-01
I discuss topics in Particle Physics applying the novel ontological formulation of Relativistic Quantum Field Theory due to David Bohm. I argument that particle physicists might too benefit from this truly novel way of thinking Physics.
On the quantum field theory in the Bohm-de Broglie interpretation
International Nuclear Information System (INIS)
In this work some characteristics of the Bohm-de Broglie interpretation in field theory. Interesting results for the field theory are found, such as the proof of the general consistency and the break of the relativistic invariance for individual processes. The methodology developed in this paper is useful as introduction for the study of quantum gravitation and cosmology in the Bohm-de Broglie interpretation
Energy Technology Data Exchange (ETDEWEB)
Pinto Neto, N.; Santini, E. Sergio [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). E-mail: nelsonpn@lafex.cbpf.br; santini@lafex.cbpf.br
2000-07-01
In this work some characteristics of the Bohm-de Broglie interpretation in field theory. Interesting results for the field theory are found, such as the proof of the general consistency and the break of the relativistic invariance for individual processes. The methodology developed in this paper is useful as introduction for the study of quantum gravitation and cosmology in the Bohm-de Broglie interpretation.
Aharonov-Bohm Effect in Lattice Abelian Higgs Theory
Chernodub, M. N.; Gubarev, F. V.; Polikarpov, M.I.
1997-01-01
We study a field-theoretical analogue of the Aharonov-Bohm effect in two-, three- and four-dimensional Abelian Higgs models; the corresponding topological interaction is proportional to the linking number of the Abrikosov vortex and the particle world trajectories. We show that the Aharonov-Bohm effect gives rise to a nontrivial interaction of charged test particles. The numerical calculations in the three-dimensional model confirm this fact.
Aharonov-Bohm effect in a Class of Noncommutative Theories
Das, A.(University of Arizona, Tucson, AZ, 85721, USA); Falomir, H.; Gamboa, J.; Mendez, F.; Nieto, M.
2011-01-01
The Aharonov-Bohm effect including spin-noncommutative effects is considered. At linear order in $\\theta$, the magnetic field is gauge invariant although spatially strongly anisotropic. Despite this anisotropy, the Schr\\"odinger-Pauli equation is separable through successive unitary transformations and the exact solution is found. The scattering amplitude is calculated and compared with the usual case. In the noncommutative Aharonov-Bohm case the differential cross section is independent of $...
Aharonov-Bohm effect in a class of noncommutative theories
Das, Ashok; Falomir, H.; Nieto, M.; Gamboa, J.; Méndez, F.
2011-08-01
The Aharonov-Bohm effect including spin-noncommutative effects is considered. At linear order in θ, the magnetic field is gauge invariant although spatially strongly anisotropic. Despite this anisotropy, the Schrödinger-Pauli equation is separable through successive unitary transformations and the exact solution is found. The scattering amplitude is calculated and compared with the usual case. In the noncommutative Aharonov-Bohm case the differential cross section is independent of θ.
Aharonov-Bohm effect in a Class of Noncommutative Theories
Das, A; Gamboa, J; Mendez, F; Nieto, M
2011-01-01
The Aharonov-Bohm effect including spin-noncommutative effects is considered. At linear order in $\\theta$, the magnetic field is gauge invariant although spatially strongly anisotropic. Despite this anisotropy, the Schr\\"odinger-Pauli equation is separable through successive unitary transformations and the exact solution is found. The scattering amplitude is calculated and compared with the usual case. In the noncommutative Aharonov-Bohm case the differential cross section is independent of $\\theta$.
On the Incompatibility of Standard Quantum Mechanics and the de Broglie-Bohm Theory
Ghose, Partha
2001-01-01
It is shown that the de Broglie-Bohm quantum theory of multi-particle systems is incompatible with the standard quantum theory of such systems unless the former is ergodic. A realistic experiment is suggested to distinguish between the two theories.
The Aharonov–Bohm effect in scattering theory
Energy Technology Data Exchange (ETDEWEB)
Sitenko, Yu.A., E-mail: yusitenko@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, National Academy of Sciences, 14-b Metrologichna Str., Kyiv, 03680 (Ukraine); Vlasii, N.D. [Physics Department, Taras Shevchenko National University of Kyiv, 64 Volodymyrska str., Kyiv, 01601 (Ukraine)
2013-12-15
The Aharonov–Bohm effect is considered as a scattering event with nonrelativistic charged particles of the wavelength which is less than the transverse size of an impenetrable magnetic vortex. The quasiclassical WKB method is shown to be efficient in solving this scattering problem. We find that the scattering cross section consists of two terms, one describing the classical phenomenon of elastic reflection and another one describing the quantum phenomenon of diffraction; the Aharonov–Bohm effect is manifested as a fringe shift in the diffraction pattern. Both the classical and the quantum phenomena are independent of the choice of a boundary condition at the vortex edge, providing that probability is conserved. We show that a propagation of charged particles can be controlled by altering the flux of a magnetic vortex placed on their way. -- Highlights: •Aharonov–Bohm effect as a scattering event. •Impenetrable magnetic vortex of nonzero transverse size. •Scattering cross section is independent of a self-adjoint extension employed. •Classical phenomenon of elastic reflection and quantum phenomenon of diffraction. •Aharonov–Bohm effect as a fringe shift in the diffraction pattern.
The Aharonov–Bohm effect in scattering theory
International Nuclear Information System (INIS)
The Aharonov–Bohm effect is considered as a scattering event with nonrelativistic charged particles of the wavelength which is less than the transverse size of an impenetrable magnetic vortex. The quasiclassical WKB method is shown to be efficient in solving this scattering problem. We find that the scattering cross section consists of two terms, one describing the classical phenomenon of elastic reflection and another one describing the quantum phenomenon of diffraction; the Aharonov–Bohm effect is manifested as a fringe shift in the diffraction pattern. Both the classical and the quantum phenomena are independent of the choice of a boundary condition at the vortex edge, providing that probability is conserved. We show that a propagation of charged particles can be controlled by altering the flux of a magnetic vortex placed on their way. -- Highlights: •Aharonov–Bohm effect as a scattering event. •Impenetrable magnetic vortex of nonzero transverse size. •Scattering cross section is independent of a self-adjoint extension employed. •Classical phenomenon of elastic reflection and quantum phenomenon of diffraction. •Aharonov–Bohm effect as a fringe shift in the diffraction pattern
A first experimental test of de Broglie-Bohm theory against standard quantum mechanics
Brida, G.; Cagliero, E.; Falzetta, G.; Genovese, M.; M. Gramegna; Novero, C.
2002-01-01
De Broglie - Bohm (dBB) theory is a deterministic theory, built for reproducing almost all Quantum Mechanics (QM) predictions, where position plays the role of a hidden variable. It was recently shown that different coincidence patterns are predicted by QM and dBB when a double slit experiment is realised under specific conditions and, therefore, an experiment can test the two theories. In this letter we present the first realisation of such a double slit experiment by using correlated photon...
Dialectical materialism and the construction of a new quantum theory: David Joseph Bohm, 1917-1992
Energy Technology Data Exchange (ETDEWEB)
Forstner, C.
2005-07-01
This paper touches on some general questions of theory construction in physics, by presenting a biographical case study of David Bohm through the perspective of Fleckian thought-collectives and their thought-style. In the 1920s a small elite of physicists established the Copenhagen Interpretation of quantum mechanics as a new thought-style in the thought-collective of the physicists. In the following decade the Copenhagen Interpretation was transferred from Europe to the USA, from one thought-collective into another, and was integrated into a specific American thought-style. David Bohm was initiated in this mode of thought during his undergraduate studies at the Pennsylvania State College and his graduate studies at Caltech and the University of California at Berkeley. (orig.)
Aharonov-Bohm order parameters for non-Abelian gauge theories
International Nuclear Information System (INIS)
The Aharonov-Bohm effect has been invoked to probe the phase structure of a gauge theory. Yet in the case of non-Abelian gauge theories, it proves difficult to formulate a general procedure that unambiguously specifies the realization of the gauge symmetry, e.g., the unbroken subgroup. In this paper we propose a set of order parameters that will do the job. We articulate the fact that any useful Aharonov-Bohm experiment necessarily proceeds in two stages: calibration and measurement. World sheets of virtual cosmic string loops can wrap around test charges, thus changing their states relative to other charges in the universe. Consequently, repeated flux measurements with test charges will not necessarily agree. This was the main stumbling block to previous attempts to construct order parameters for non-Abelian gauge theories. In those works, the particles that one uses for calibration and subsequent measurement are stored in separate ''boxes.'' By storing all test particles in the same ''box'' we show how quantum fluctuations can be overcome. The importance of gauge fixing is also emphasized. copyright 1995 The American Physical Society
The Aharonov-Bohm effect in a spatially confining theory based on a turbulent fluid
Antonov, Dmitri
2012-01-01
Wilson loops in a turbulent fluid are shown to respect a specific area law corresponding to the Kolmogorov scaling. This law leads to the condensation of a complex-valued scalar field minimally coupled to the velocity field. We use this finding to estimate a v.e.v. of the dual Higgs field, which appears in the hydrodynamic description of a spatially confining dual Landau-Ginzburg theory. The temperature dependence of all other parameters of this theory is found upon a comparison with the spatial string tension and the chromo-magnetic vacuum correlation length of the Yang-Mills gluon plasma. In particular, a nonperturbative contribution to the shear viscosity of the dual fluid comes out exponentially suppressed with temperature. Interactions of the dual Abrikosov vortices with excitations of the fluid yield a long-range Aharonov-Bohm effect. This effect is shown to take place for all but calculated discrete values of the product of the kinematic viscosity of the fluid to the coupling constant of the dual Higgs...
Energy Technology Data Exchange (ETDEWEB)
Pinto-Neto, N.; Santini, E. Sergio. E-mail: nelsonpn@lafex.cbpf.br; santini@lafex.cbpf.br
2000-12-01
We consider quantum geometrodynamics and parametrized quantum field theories in the frame-work of the Bohm-de Broglie interpretation. In the first case, and following the lines of our previous work, where a Hamiltonian formalism for the bohmian trajectories was constructed, we show the consistency of the theory for any quantum potential, completing the scenarios for canonical quantum cosmology presented there. In the latter case, we prove the consistency of scalar field theory in Minkowski spacetime for any quantum potential, and we show, using this alternative Hamiltonian method, a concrete example already known in the literature where Lorentz invariance of individual events is broken. (author)
International Nuclear Information System (INIS)
We consider quantum geometrodynamics and parametrized quantum field theories in the frame-work of the Bohm-de Broglie interpretation. In the first case, and following the lines of our previous work, where a Hamiltonian formalism for the bohmian trajectories was constructed, we show the consistency of the theory for any quantum potential, completing the scenarios for canonical quantum cosmology presented there. In the latter case, we prove the consistency of scalar field theory in Minkowski spacetime for any quantum potential, and we show, using this alternative Hamiltonian method, a concrete example already known in the literature where Lorentz invariance of individual events is broken. (author)
Scattering theory and the Aharonov-Bohm effect in quasiclassical physics
International Nuclear Information System (INIS)
Research highlights: → Scattering Aharonov-Bohm effect. → Short-wavelength limit of scattered nonrelativistic particles. → Fraunhofer diffraction in the forward direction. → Fresnel diffraction in the forward region in conical space. → Enclosed magnetic flux is a gate for the propagation of quasiclassical particles. - Abstract: Scattering of a nonrelativistic quantum-mechanical particle by an impenetrable magnetic vortex is considered. The nonvanishing transverse size of the vortex is taken into account, and the limit of short, as compared to this size, wavelengths of the scattered particle is analyzed. We show that the scattering Aharonov-Bohm effect persists in the quasiclassical limit owing to the diffraction persisting in the short-wavelength limit. As a result, the vortex flux serves as a gate for the propagation of short-wavelength, almost classical, particles. This quasiclassical effect is more feasible to experimental detection in the case when space outside the vortex is conical.
Directory of Open Access Journals (Sweden)
E. V. B. Leite
2015-01-01
Full Text Available Based on the Kaluza-Klein theory, we study the Aharonov-Bohm effect for bound states for a relativistic scalar particle subject to a Coulomb-type potential. We introduce this scalar potential as a modification of the mass term of the Klein-Gordon equation, and a magnetic flux through the line element of the Minkowski spacetime in five dimensions. Then, we obtain the relativistic bound states solutions and calculate the persistent currents.
Bohm Confirmed by NonRelativistic Quark Model
Smith, F T
1998-01-01
The effectiveness of the NonRelativistic Quark Model of hadrons can be explained by Bohm's quantum theory applied to a fermion confined in a box, in which the fermion is at rest because its kinetic energy is transformed into PSI-field potential energy. Since that aspect of Bohm's quantum theory is not a property of most other formulations of quantum theory, the effectiveness of the NonRelativistic Quark Model confirms Bohm's quantum theory as opposed to those others.
De Raedt, H.; Katsnelson, M. I.; Donker, H. C.; Michielsen, K.
2015-01-01
We propose and develop the thesis that the quantum theoretical description of experiments emerges from the desire to organize experimental data such that the description of the system under scrutiny and the one used to acquire the data are separated as much as possible. Application to the Stern-Gerlach and Einstein-Podolsky-Rosen-Bohm experiments are shown to support this thesis. General principles of logical inference which have been shown to lead to the Schr\\"odinger and Pauli equation and ...
Trammel, G. T.
1964-01-01
Aharonov-bohm paradox involving charge particle interaction with stationary current distribution showing that vector potential term in canonical momenta expression represents electromagnetic field momentum
Maciel, Duan
This dissertation addresses the common elements between ancient Celtic mystical doctrines and philosophy and David Bohm's unique theories in quantum physics through a Jungian lens, using research based in dialogical hermeneutics. The premise of this dissertation is that psi, or the probability wave function of quantum physics, and its world of potentia are the same entities as Jung's objective psyche (or collective unconscious) and its domain, the unus mundus. In addition, the study explores the remarkable similarity between the ancient Celts' Otherworld, quantum physics' world of potentia, and Jung's unus mundus. These similarities argue for an in-depth Jungian analysis of this important but largely neglected mythology. The study explores the supposition, based partially on physicist David Bohm's theories of the implicate and explicate orders, that the above world of potentia intertwines with our three-dimensional world in a reciprocal creativity, designed to enhance both worlds. The study further advocates a greater emphasis on the creative arts therapies in the therapeutic situation, based on the above reciprocity. It is argued that this emphasis on creativity in the temenos may activate a profound "quantum leap" of insight in the analysand, most likely due to the reciprocity in which the objective psyche responds uniquely to the particular and individual creativity offered in order to heal the personal psyche. As we creatively access the objective psyche, that entity responds in kind, giving us new understanding and allowing us to change our attitudes and to further individuation, which in turn enhances the objective psyche. In addition, a psyche of reality is postulated in which Jung's concept of the objective psyche is expanded from the collective unconscious of humankind to a collective unconscious of All That Is, reflecting the findings in quantum physics that our universe is self-aware, organic, and holistic rather than mechanical and fragmented.
Aharonov-Bohm Effect and Disclinations in an Elastic Medium
Furtado, Claudio; Carvalho, A. M. de M.; Ribeiro, C. A. de Lima
2006-01-01
In this work we investigate quasiparticles in the background of defects in solids using the geometric theory of defects. We use the parallel transport matrix to study the Aharonov-Bohm effect in this background. For quasiparticles moving in this effective medium we demonstrate an effect similar to the gravitational Aharonov- Bohm effect. We analyze this effect in an elastic medium with one and $N$ defects.
Classical Electrodynamics without Fields and the Aharonov-Bohm effect
Stefanovich, Eugene V.
2008-01-01
The Darwin-Breit Hamiltonian is applied to the Aharonov-Bohm experiment. In agreement with the standard Maxwell-Lorentz theory, the force acting on electrons from infinite solenoids or ferromagnetic rods vanishes. However, the interaction energies and phase factors of the electron wave packets are non-zero. This allows us to explain the Aharonov-Bohm effect without involvement of electromagnetic potentials, fields, and topological properties of space.
Aharonov-Bohm effect revisited
Eskin, Gregory
2015-01-01
Aharonov-Bohm effect is a quantum mechanical phenomenon that attracted the attention of many physicists and mathematicians since the publication of the seminal paper of Aharonov and Bohm [1] in 1959. We consider different types of Aharonov-Bohm effect such as magnetic AB effect, electric AB effect, combined electromagnetic AB effect, AB effect for the Schr\\"odinger equations with Yang-Mills potentials, and the gravitational analog of AB effect. We shall describe different approaches to prove ...
Aharonov-Bohm effect in spherical billiard
Institute of Scientific and Technical Information of China (English)
Dehua Wang
2007-01-01
Using Gutzwiller's periodic orbit theory, we study the quantum level density of a spherical billiard in the presence of a magnetic flux line added at its center, especially discuss the influence of the magnetic flux strength on the quantum level density. The Fourier transformed quantum level density of this system has allowed direct comparison between peaks in the level density and the length of the periodic orbits. For particular magnetic flux strength, the amplitude of the peaks in the level density decreased and some of the peaks disappeared. This result suggests that Aharonov-Bohm effect manifests itself through the cancellation of periodic orbits. This phenomenon will provide a new experimental testing ground for exploring Aharonov-Bohm effect.
Einstein, Bohm, and Leggett-Garg
Bacciagaluppi, Guido
In a recent paper, I have analysed and criticised Leggett and Garg's argument to the effect that oscopic realism contradicts quantum mechanics, by contrasting their assumptions to the example of Bell's stochastic pilot-wave theories, and have applied Dzhafarov and Kujala's analysis of contextuality in the presence of signalling to the case of the Leggett-Garg inequalities. In this chapter, I discuss more in general the motivations for oscopic realism, taking a cue from Einstein's criticism of the Bohm theory, then go on to summarise my previous results, with a few additional comments on other recent work on Leggett and Garg.
International Nuclear Information System (INIS)
Quantum mechanics teaches us that matter consists of waves. Interference of matter waves gives rise to delicate effects best illustrated by the double slit experiment. Aharonov and Bohm showed that the interference pattern of electrons in a multiply connected region can be influenced by magnetic fields outside that region. This surprising effect (now called the Aharonov-Bohm effect) has been measured in the laboratory. The process of understanding and coming to terms with this effect has deepened our understanding of both quantum mechanics and electromagnetism. This paper gives an elementary account of the Aharonov-Bohm effect. (author). 13 refs., 2 figs
Global analogue of the Aharonov-Bohm effect
International Nuclear Information System (INIS)
This thesis deals with a global analogue of the Aharonov-Bohm effect previously pointed out by other authors. The effect was not well understood because the pure Aharonov-Bohm cross section was thought to be merely an approximate low energy limit. This thesis provides a detailed analysis and reveals that in the particular model considered, there is an exact Aharonov-Bohm cross section over the energy range that a mass splitting occurs. At energies slightly above the mass splitting, the effect has completely disappeared and there is effectively no scattering at large distances. This is a curious observation as it was previously thought that a global theory would not act exactly like a local one over an extended range of energies. It begs the heretical speculation that experimentally observed forces modelled with Lagrangians possessing local symmetries may have an underlying global theory
Jones-Smith, Katherine; Vachaspati, Tanmay
2009-01-01
A solenoid oscillating in vacuum will pair produce charged particles due to the Aharonov-Bohm (AB) interaction. We calculate the radiation pattern and power emitted for charged scalar particles. We extend the solenoid analysis to cosmic strings, and find enhanced radiation from cusps and kinks on loops. We argue by analogy with the electromagnetic AB interaction that cosmic strings should emit photons due to the gravitational AB interaction of fields in the conical spacetime of a cosmic string. We calculate the emission from a kink and find that it is of similar order as emission from a cusp, but kinks are vastly more numerous than cusps and may provide a more interesting observational signature.
Quantum cosmology from the de Broglie–Bohm perspective
International Nuclear Information System (INIS)
We review the main results that have been obtained in quantum cosmology from the perspective of the de Broglie–Bohm quantum theory. As it is a dynamical theory of assumed objectively real trajectories in the configuration space of the physical system under investigation, this quantum theory is not essentially probabilistic and dispenses the collapse postulate, turning it suitable to be applied to cosmology. In the framework of minisuperspace models, we show how quantum cosmological effects in the de–Broglie-Bohm approach can avoid the initial singularity, and isotropize the Universe. We then extend minisuperspace in order to include linear cosmological perturbations. We present the main equations which govern the dynamics of quantum cosmological perturbations evolving in non-singular quantum cosmological backgrounds, and calculate some of their observational consequences. These results are not known how to be obtained in other approaches to quantum theory. In the general case of full superspace, we enumerate the possible structures of quantum space and time that emerge from the de Broglie–Bohm picture. Finally, we compare some of the results coming from the de Broglie–Bohm theory with other approaches, and discuss the physical reasons for some discrepancies that occur. (topical review)
Aharonov-Bohm effect in many-electron quantum rings
Kotimaki, V.; Rasanen, E.
2010-01-01
The Aharonov-Bohm effect is investigated in two-dimensional, single-terminal quantum rings in magnetic fields by using time-dependent density-functional theory. We find multiple transport loops leading to the oscillation periods of h/(en), where n is the number of loops. We show that the Aharonov-Bohm oscillations are relatively weakly affected by the electron-electron interactions, whereas the ring width has a strong effect on the characteristics of the oscillations. Our results propose that...
A de Broglie-Bohm Like Model for Dirac Equation
Chavoya-Aceves, O
2003-01-01
A de Broglie-Bohm like model of Dirac equation, that leads to the correct Pauli equations for electrons and positrons in the low-speed limit, is presented. Under this theoretical framework, that affords an interpretation of the \\emph{quantum potential}, the main assumption of the de Broglie-Bohm theory--that the local momentum of particles is given by the gradient of the phase of the wave function--wont be accurate. Also, the number of particles wont be locally conserved. Furthermore, the representation of physical systems through wave functions wont be complete.
Anomalous aharonov-bohm gap oscillations in carbon nanotubes.
Sangalli, Davide; Marini, Andrea
2011-10-12
The gap oscillations caused by a magnetic flux penetrating a carbon nanotube represent one of the most spectacular observations of the Aharonov-Bohm effect at the nanoscale. Our understanding of this effect is, however, based on the assumption that the electrons are strictly confined on the tube surface, on trajectories that are not modified by curvature effects. Using an ab initio approach based on density functional theory, we show that this assumption fails at the nanoscale inducing important corrections to the physics of the Aharonov-Bohm effect. Curvature effects and electronic density that is spilled out of the nanotube surface are shown to break the periodicity of the gap oscillations. We predict the key phenomenological features of this anomalous Aharonov-Bohm effect in semiconductive and metallic tubes and the existence of a large metallic phase in the low flux regime of multiwalled nanotubes, also suggesting possible experiments to validate our results. PMID:21805987
Lorentz violation correction to the Aharonov-Bohm scattering
Anacleto, M. A.
2015-10-01
In this paper, using a (2 +1 )-dimensional field theory approach, we study the Aharonov-Bohm (AB) scattering with Lorentz symmetry breaking. We obtain the modified scattering amplitude to the AB effect due to the small Lorentz violation correction in the breaking parameter and prove that up to one loop the model is free from ultraviolet divergences.
Lorentz violation correction to the Aharonov-Bohm scattering
Anacleto, M A
2015-01-01
In this paper, using a (2+1)-dimensional field theory approach we study the Aharonov-Bohm (AB) scattering with Lorentz symmetry breaking. We obtain the modified scattering amplitude to the AB effect due to the small Lorentz violation correction in breaking parameter and prove that up to one-loop the model is free from ultraviolet divergences.
Non-traditional Aharonov-Bohm effects in condensed matter
International Nuclear Information System (INIS)
In 1959, Aharonov and Bohm proposed an elegant experiment demonstrating observability of electromagnetic potentials (or, which is the same, the non-locality of the wave function of charged particles) in quantum mechanics. This paper discusses the Aharonov-Bohm effect, based on the fundamental principles of quantum theory, as the superposition principles, the quantum character of motion of particles and locality of the interaction of a charge with an electromagnetic potential Lint = jμAμ. It is thus no wonder that the Aharonov-Bohm's paper aroused much dispute which is still ongoing. Originally, the Aharonov-Bohm effect (ABE) means the dependence of the interference pattern on the magnetic fluid flux φ in a Gendaken experiment on a coherent electron beam in the field of an infinitely thin solenoid. Later, however, it became common to refer to the Aharonov-Bohm phenomenon wherever the characteristics of systems under study appear to depend on the flux φ in the absence of electric and magnetic fields. In this sense, it was highly interesting to analyze the ABE in condensed media (the many-particle Aharonov-Bohm effect), in particular to study the dependence of the thermodynamic and kinetic characteristics, e.g., of metal on the flux. Such a problem was first discussed by Byers and Yang who formulated the general theorems related to the ABE in conducting condensed media. The next important step was the work of Kulik who formulated a concrete model and calculated the flux-dependent contribution to the metal free energy and provided a first clear formulation of the requirements to reveal
Persistent Currents in the Double Aharonov-Bohm Ring Connected to Electron Reservoirs
International Nuclear Information System (INIS)
We study persistent currents in the double Aharonov-Bohm ring connected to two electron reservoirs by quantum waveguide theory. It is found that the persistent currents in the double Aharonov-Bohm ring depend on the direction of the current flow from one reservoir to another. When the direction of the current flow reverses, the persistent current in each ring of the double Aharonov-Bohm ring changes. If the two rings are of the same size, the persistent currents in the left and the right rings exchange at the reversal of the current flow direction.
Gravitational Aharonov-Bohm effect in graphene
International Nuclear Information System (INIS)
Full text. We would like to suggest that the Einstein theory of gravitation in 2+1 dimensions can be seen and even tested experimentally in possible realizable condensed matter materials, such as graphene. Deforming a graphene sheet in a conical surface this system makes possible the experimental study of relativistic massless quasiparticles with charge e on a two-dimensional, or equivalently, in the 'gravitational field (deficit angle) of a 'pointlike particle' of mass M (cone tip). This surface is locally flat. Then we study a kind of gravitational Aharonov-Bohm effect in a graphene sheet with a wedge removed and edges identified, i.e., a graphitic cone. The angular defect gives rise to a mismatch of the components of the graphene's relativistic charged quasiparticle wavefunctions (spinors) upon closed parallel transport around the (singular) cone tip. Such an affect should affect the basic electronic properties in 'conical graphene' as compared with their planar counterpart and it could be, in principle, detected experimentally. It is similar to the usual Aharonov-Bohm effect in electromagnetism, but simulated as a gravitational field by a deficit angle incorporated in the material. In principle, the effect proposed here could be detected by interference experiments in structured materials by measurements of the electronic transport in these graphitic materials and their relationships with the changes calculated in the quasiparticle wavefunctions. Therefore it could make available interesting probes to the Einstein theory of general relativity in two spatial dimensions. Then we propose a way of verifying, in a microscopic scale, some predictions of a theory that is usual. (author)
Generalized Aharonov-Bohm experiments with neutrons
International Nuclear Information System (INIS)
The Aharonov-Bohm effects are generally regarded as direct manifestations of the property, that potentials are affecting quantum systems in a way significantly different from the classical case. This paper searches for generalizations for the neutron case, where still some of the features of the original Aharonov-Bohm effects are maintained. This is based on operational analogy and does not involve any interpretive or epistemological questions. The author identifies operationally significant features of the Aharonov-Bohm effects with a thorough operational analysis. The electric and the magnetic Aharonov-Bohm effects are analyzed separately; this procedure leads to the identification of common features
Relativistic scalar Aharonov-Bohm scattering
International Nuclear Information System (INIS)
Full text follows: We study the scattering of a charged spin zero relativistic particle from a fixed, thin, infinitely long solenoid in the framework of the first quantization comparing with the results obtained using the field theory approach. The scattering amplitude, within the viewpoint of the relativistic quantum mechanics, can be calculated exactly as a mimic of the nonrelativistic case, either in the original Aharonov-Bohm way or by using the Berry's magnetization scheme. To implement the perturbative analysis within the first-quantized treatment, we consider the Feshbach-Villars two-component formalism of the Klein-Gordon equation. It is shown that the first Born approximation gives an incomplete result while the second order is divergent as occurs in the nonrelativistic counterpart. We search for additional interactions which might provide the appropriated renormalization of the amplitude. It is shown that the addition of a phenomenological magnetic interaction (naively inspired in the spin half case) generates the correct first order term in the the nonrelativistic leading order but it does not give reasonable results in higher orders. We demonstrate that an external delta potential is necessary to reproduce the correct perturbation expansion as happens in the nonrelativistic situation. However, it does not produce the same effect of the quartic self-interaction in the second quantized treatment, which corresponds to the two body sector of a scalar Chern-Simons theory. In the later case, additional contributions coming from vacuum polarization and vertex corrections spoil the scale invariance characteristic of the nonrelativistic Aharonov-Bohm scattering. (author)
Gonzalez, Javier; Gimenez, Xavier; Bofill, Josep Maria
2007-01-01
First, we use the theory of characteristics of first order partial differential equations to derive the guiding equation directly from the Quantum Evolution Equation (QEE). After obtaining the general result, we apply it to a set of evolution equations (Schroedinger, Pauli, Klein-Gordon, Dirac) to show how the guiding equation is, actually, the characteristic velocity of the corresponding matter field equations.
Nonlocality of the Aharonov-Bohm effect
Aharonov, Yakir; Cohen, Eliahu; Rohrlich, Daniel
2016-04-01
Although the Aharonov-Bohm and related effects are familiar in solid-state and high-energy physics, the nonlocality of these effects has been questioned. Here we show that the Aharonov-Bohm effect has two very different aspects. One aspect is instantaneous and nonlocal; the other aspect, which depends on entanglement, unfolds continuously over time. While local, gauge-invariant variables may occasionally suffice for explaining the continuous aspect, we argue that they cannot explain the instantaneous aspect. Thus the Aharonov-Bohm effect is, in general, nonlocal.
The multisolenoid Aharonov-Bohm effect
International Nuclear Information System (INIS)
The thesis summarizes, extends and discusses the author's achievements published in Phys. Lett. A 142, 1989, p. 5; J. Math. Phys. 32, 1991, p.13; and Phys. Lett. A 161, 1991, p. 13. The following topics are dealt with: (i) the Green function for the two-solenoid Aharonov-Bohm effect; (ii) application of Krein's formula to the multisolenoid Aharonov-Bohm effect; (iii) the scattering matrix for the two-solenoid Aharonov-Bohm effect; and (iv) the differential cross section. Reprints of the 3 publications are included. (P.A.)
About nature of Aharonov-Bohm effect
International Nuclear Information System (INIS)
The problem on the Aharonov-Bohm effect is discussed. The method of surplus potentials for solving boundary-value problem tasks of the anisotropic media electrodynamics is considered. General notion on the vector potential in the uniaxial medium is obtained. The relationship of the zero field potentials with gauge transformation is established. The vector potential structure for the Aharonov-Bohm magnetostatic effect in particular for a solenoid with alternating current is considered. It is shown that presence of the zero field potentials in the general structure may be the cause of the Aharonov-Bohm effect
Lambda-mu-calculus and Bohm's theorem
David, René; Py, Walter
2001-01-01
The lambda mu-calculus is an extension of the lambda-calculus that has been introduced by M. Parigot to give an algorithmic content to classical proofs. We show that Bohm's theorem fails in this calculus.
Aharonov-Bohm effects in nanostructures
Gurtovoi, V. L.; Nikulov, A. V.; Tulin, V. A.
2009-01-01
Measurements of the Little-Parks oscillations at measuring current much lower than the persistent current give unambiguous evidence of the dc current flowing against the force of the dc electric field because of the Aharonov-Bohm effect. This result can assume that an additional force is needed for description of the Aharonov-Bohm effect observed in semiconductor, normal metal and superconductor nanostructures in contrast to the experimental result obtained recently for the case of the two-sl...
Nonlocality of the Aharonov-Bohm Effect
Aharonov, Yakir; Cohen, Eliahu; Rohrlich, Daniel
2015-01-01
Although the Aharonov-Bohm and related effects are familiar in solid state and high energy physics, the nonlocality of these effects has been questioned. Here we show, for the first time, that the Aharonov-Bohm effect has two very different aspects. One aspect is instantaneous and nonlocal; the other aspect, which depends on entanglement, unfolds continuously over time. While local, gauge-invariant variables may occasionally suffice for explaining the continuous aspect, we argue that they can...
What is Surrealistic about Bohm Trajectories?
Cunha, M. O. Terra
1998-01-01
We discuss interferometers in Bohmian quantum mechanics. It is shown that, with the correct configuration space, Bohm trajectories in a which way interferometer are not surrealistic, but behaves exactly as common sense suggests. Some remarks about a way to generalize Bohmian mechanics to treat density matrix are also made. PACS: 03.65.Bz, 03.75.Dg Key words: Bohm Trajectories, Which Way Interferometers, ESSW
On the role of potentials in the Aharonov-Bohm effect
Vaidman, Lev
2011-01-01
There is a consensus today that the the main lesson of the Aharonov-Bohm effect is that a picture of electromagnetism based on the local action of the field strengths is not possible in quantum mechanics. Contrary to this statement it is argued here that when the source of the electromagnetic potential is treated in the framework of quantum theory, the Aharonov-Bohm effect can be explained without the notion of potentials. It is explained by local action of the field of the electron on the so...
The K-Theoretic Formulation of D-Brane Aharonov-Bohm Phases
Aaron R. Warren
2012-01-01
The topological calculation of Aharonov-Bohm phases associated with D-branes in the absence of a Neveu-Schwarz B-field is explored. The K-theoretic classification of Ramond-Ramond fields in Type II and Type I theories is used to produce formulae for the Aharonov-Bohm phase associated with a torsion flux. A topological construction shows that K-theoretic pairings to calculate such phases exist and are well-defined. An analytic perspective is then taken, obtaining a means for determining Aharon...
Computer Simulation of Einstein-Podolsky-Rosen-Bohm Experiments
de Raedt, H.; Michielsen, K.
2016-07-01
We review an event-based simulation approach which reproduces the statistical distributions of quantum physics experiments by generating detection events one-by-one according to an unknown distribution and without solving a wave equation. Einstein-Podolsky-Rosen-Bohm laboratory experiments are used as an example to illustrate the applicability of this approach. It is shown that computer experiments that employ the same post-selection procedure as the one used in laboratory experiments produce data that is in excellent agreement with quantum theory.
Quantum spin transport through Aharonov-Bohm ring with a tangent magnetic field
Institute of Scientific and Technical Information of China (English)
Li Zhi-Jian
2005-01-01
Quantum spin transport in a mesoscopic Aharonov-Bohm ring with two leads subject to a magnetic field with circular configuration is investigated by means of one-dimensional quantum waveguide theory. Within the framework magnetic flux or by the tangent magnetic field. In particular, the spin flips can be induced by hopping the AB magnetic flux or the tangent field.
Einstein-Podolsky-Rosen-Bohm laboratory experiments : Data analysis and simulation
De Raedt, H.; Michielsen, K.; Jin, F.; DAriano, M; Fei, SM; Haven, E; Hiesmayr, B; Jaeger, G; Khrennikov, A; Larsson, JA
2012-01-01
Data produced by laboratory Einstein-Podolsky-Rosen-Bohm (EPRB) experiments is tested against the hypothesis that the statistics of this data is given by quantum theory of this thought experiment. Statistical evidence is presented that the experimental data, while violating Bell inequalities, does n
Tunable exciton Aharonov-Bohm effect in a quantum ring
International Nuclear Information System (INIS)
We studied the optical Aharonov-Bohm effect for an exciton in a semiconductor quantum ring. A perpendicular electric field applied to a quantum ring with large height, is able to tune the exciton ground state energy such that it exhibits a weak observable Aharonov-Bohm oscillations. This Aharonov-Bohm effect is tunable in strength and period.
Locality and topology in the molecular Aharonov-Bohm effect
Sjöqvist, Erik
2001-01-01
It is shown that the molecular Aharonov-Bohm effect is neither nonlocal nor topological in the sense of the standard magnetic Aharonov-Bohm effect. It is further argued that there is a close relationship between the molecular Aharonov-Bohm effect and the Aharonov-Casher effect for an electrically neutral spin$-{1/2}$ particle encircling a line of charge.
Aharonov–Bohm effects in magnetohydrodynamics
Energy Technology Data Exchange (ETDEWEB)
Yahalom, Asher, E-mail: asya@ariel.ac.il [Isaac Newton Institute for Mathematical Sciences, 20 Clarkson Road, Cambridge CB3 0EH (United Kingdom); Ariel University, Ariel 40700 (Israel)
2013-10-30
It is shown that an Aharonov–Bohm (AB) effect exists in magnetohydrodynamics (MHD). This effect is best described in terms of the MHD variational variables (Kats, 2004; Yahalom and Lynden-Bell, 2008; Yahalom, 2010) [1,10,12]. If a MHD flow has a non-trivial topology some of the functions appearing in the MHD Lagrangian are non-single-valued. These functions have properties similar to the phases in the AB celebrated effect (Aharonov and Bohm, 1959; van Oudenaarden et al., 1998) [2,3]. While the manifestation of the quantum AB effect is in interference fringe patterns (Tonomura et al., 1982) [4], the manifestation of the MHD Aharonov–Bohm effects are through new dynamical conservation laws.
Aharonov–Bohm effects in magnetohydrodynamics
International Nuclear Information System (INIS)
It is shown that an Aharonov–Bohm (AB) effect exists in magnetohydrodynamics (MHD). This effect is best described in terms of the MHD variational variables (Kats, 2004; Yahalom and Lynden-Bell, 2008; Yahalom, 2010) [1,10,12]. If a MHD flow has a non-trivial topology some of the functions appearing in the MHD Lagrangian are non-single-valued. These functions have properties similar to the phases in the AB celebrated effect (Aharonov and Bohm, 1959; van Oudenaarden et al., 1998) [2,3]. While the manifestation of the quantum AB effect is in interference fringe patterns (Tonomura et al., 1982) [4], the manifestation of the MHD Aharonov–Bohm effects are through new dynamical conservation laws.
Generalized Bohm Criterion for Electronegative Complex Plasma
International Nuclear Information System (INIS)
In this work, we have generalized the computation of Bohm criterion for electronegative complex plasma. For this, we have established a one-dimensional, unmagnetized and stationary theoretical model where the positive ions and dust particles are modeled by fluid equations. The electrons and negative ions are considered in thermodynamic equilibrium; therefore they obey to Boltzmann's statistic. In this case, the numerical results show that the generalized Bohm velocity is small compared to the classical value. For electronegative dusty plasma, the corrections are less important.
Thermoelectric effect in Aharonov-Bohm structures
Lu, Xin; Wang, Jian-Sheng; Morrel, William G.; Ni, Xiaoxi; Wu, Chang-Qin; Li, Baowen
2015-01-01
The thermoelectric effects of a single Aharonov-Bohm (SAB) ring and coupled double Aharonov-Bohm (DAB) rings have been investigated on a theoretical basis, taking into account the contributions of both electrons and phonons to the transport process by using the nonequilibrium Green's function technique. The thermoelectric figure of merit of the coupled DAB rings cannot be predicted directly by combining the values of two SAB ring systems due to the contribution of electron-phonon interaction to coupling between the two sites connecting the rings. We find that thermoelectric efficiency can be optimized by modulating the phases of the magnetic flux threading the two rings.
Aharonov-Bohm Constraint for Fusion
Yahalom, Asher
It was shown that an Aharonov-Bohm (AB) effect exists in magnetohydrodynamics (MHD). This effect is best described in terms of the MHD variational variables. If a MHD flow has a non trivial topology some of the functions appearing in the MHD Lagrangian are non-single valued. Some of those functions are analogue to the phases in the AB celebrated effect. While the manifestation of the quantum AB effect is in interference fringe patterns, the manifestation of the MHD Aharonov-Bohm effect is through a new dynamical conservation law. This local conservation law will be shown to constrain the dynamics of MHD flows including fusion scenarios. Bibliography
Thermoelectric effect in Aharonov-Bohm structures.
Lu, Xin; Wang, Jian-Sheng; Morrel, William G; Ni, Xiaoxi; Wu, Chang-Qin; Li, Baowen
2015-01-28
The thermoelectric effects of a single Aharonov-Bohm (SAB) ring and coupled double Aharonov-Bohm (DAB) rings have been investigated on a theoretical basis, taking into account the contributions of both electrons and phonons to the transport process by using the nonequilibrium Green's function technique. The thermoelectric figure of merit of the coupled DAB rings cannot be predicted directly by combining the values of two SAB ring systems due to the contribution of electron-phonon interaction to coupling between the two sites connecting the rings. We find that thermoelectric efficiency can be optimized by modulating the phases of the magnetic flux threading the two rings. PMID:25537848
Aharonov-Bohm Effect and Hidden Photons
Arias, Paola
2013-01-01
Signs of hypothetical light gauge bosons from a hidden sector may appear in Aharonov-Bohm-like experiments. The absence of signal in carried on experiments allow us to set a modest constraint to the mass and coupling constant of these particles. Our findings open the possibility to exploit the leaking of hidden magnetic field in a different setup of experiments.
On the Aharonov-Bohm diffusion
International Nuclear Information System (INIS)
The diffusion of a charged particle by a singular flux tube is revisited. A simple and rigourous derivation shows that the action of the propagator on an incident plane wave precisely yields the Aharonov-Bohm diffusion amplitude. The forward diffusion is discussed as well as the singularity of the interaction at the position of the flux tube. (orig.)
Is Bohm's Interpretation Consistent with Quantum Mechanics?
Directory of Open Access Journals (Sweden)
Michael Nauenberg
2014-08-01
Full Text Available The supposed equivalence of the conventional interpretation of quantum mechanics with Bohm's interpretation is generally demonstrated only in the coordinate representation. It is shown, however, that in the momentum representation this equivalence is not valid.Quanta 2014; 3: 43–46.
The Aharonov-Bohm effect and Tonomura et al. experiments: Rigorous results
International Nuclear Information System (INIS)
The Aharonov-Bohm effect is a fundamental issue in physics. It describes the physically important electromagnetic quantities in quantum mechanics. Its experimental verification constitutes a test of the theory of quantum mechanics itself. The remarkable experiments of Tonomura et al. ['Observation of Aharonov-Bohm effect by electron holography', Phys. Rev. Lett 48, 1443 (1982) and 'Evidence for Aharonov-Bohm effect with magnetic field completely shielded from electron wave', Phys. Rev. Lett 56, 792 (1986)] are widely considered as the only experimental evidence of the physical existence of the Aharonov-Bohm effect. Here we give the first rigorous proof that the classical ansatz of Aharonov and Bohm of 1959 ['Significance of electromagnetic potentials in the quantum theory', Phys. Rev. 115, 485 (1959)], that was tested by Tonomura et al., is a good approximation to the exact solution to the Schroedinger equation. This also proves that the electron, that is, represented by the exact solution, is not accelerated, in agreement with the recent experiment of Caprez et al. in 2007 ['Macroscopic test of the Aharonov-Bohm effect', Phys. Rev. Lett. 99, 210401 (2007)], that shows that the results of the Tonomura et al. experiments can not be explained by the action of a force. Under the assumption that the incoming free electron is a Gaussian wave packet, we estimate the exact solution to the Schroedinger equation for all times. We provide a rigorous, quantitative error bound for the difference in norm between the exact solution and the Aharonov-Bohm Ansatz. Our bound is uniform in time. We also prove that on the Gaussian asymptotic state the scattering operator is given by a constant phase shift, up to a quantitative error bound that we provide. Our results show that for intermediate size electron wave packets, smaller than the ones used in the Tonomura et al. experiments, quantum mechanics predicts the results observed by Tonomura et al. with an error bound smaller than 10
The electric Aharonov-Bohm effect
International Nuclear Information System (INIS)
The seminal paper of Aharonov and Bohm [Phys. Rev. 115, 485 (1959)] is at the origin of a very extensive literature in some of the more fundamental issues in physics. They claimed that electromagnetic fields can act at a distance on charged particles even if they are identically zero in the region of space where the particles propagate, that the fundamental electromagnetic quantities in quantum physics are not only the electromagnetic fields but also the circulations of the electromagnetic potentials; what gives them a real physical significance. They proposed two experiments to verify their theoretical conclusions. The magnetic Aharonov-Bohm effect, where an electron is influenced by a magnetic field that is zero in the region of space accessible to the electron, and the electric Aharonov-Bohm effect where an electron is affected by a time-dependent electric potential that is constant in the region where the electron is propagating, i.e., such that the electric field vanishes along its trajectory. The Aharonov-Bohm effects imply such a strong departure from the physical intuition coming from classical physics that it is no wonder that they remain a highly controversial issue after more than fifty years, in spite of the fact that they are discussed in most of the text books in quantum mechanics. The magnetic case has been studied extensively. The experimental issues were settled by the remarkable experiments of Tonomura et al. [Phys. Rev. Lett. 48, 1443 (1982); Phys. Rev. Lett. 56, 792 (1986)] with toroidal magnets, that gave a strong evidence of the existence of the effect, and by the recent experiment of Caprez et al. [Phys. Rev. Lett. 99, 210401 (2007)] that shows that the results of the Tonomura et al. experiments cannot be explained by the action of a force. The theoretical issues were settled by Ballesteros and Weder [Commun. Math. Phys. 285, 345 (2009); J. Math. Phys. 50, 122108 (2009); Commun. Math. Phys. 303, 175 (2011)] who rigorously proved that quantum
The Aharonov-Bohm effect in neutral liquids
International Nuclear Information System (INIS)
The Aharonov-Bohm effect was discovered as a quantum-mechanical effect for charged particles, but it has its counterpart in classical wave mechanics. The Aharonov-Bohm interference arises at the scattering of a sound wave by a vortex in classical and quantum hydrodynamics. This interference leads to a transverse force between quasiparticles and vortices in superfluids and superconductors. The Aharonov-Bohm effect was also generalized to neutral particles with magnetic or electric dipole momenta. The Aharonov-Bohm effect for charge particles and its modification for magnetic momenta (the Aharonov-Casher effect) have already been experimentally observed, and the efforts to detect the Aharonov-Bohm effect for electrically polarized neutral particles are on the way. A possible system for this detection is a Bose-condensate of excitons in a double quantum well. Observation of the Aharonov-Bohm effect in this system would provide direct evidence of Bose-Einstein condensation.
Hidden superconformal symmetry of the spinless Aharonov-Bohm system
International Nuclear Information System (INIS)
A hidden supersymmetry is revealed in the spinless Aharonov-Bohm problem. The intrinsic supersymmetric structure is shown to be intimately related to the scale symmetry. As a result, a bosonized superconformal symmetry is identified in the system. Different self-adjoint extensions of the Aharonov-Bohm problem are studied in the light of this superconformal structure and interacting anyons. The scattering problem of the original Aharonov-Bohm model is discussed in the context of the revealed supersymmetry.
Locality of the Aharonov-Bohm-Casher effect
Kang, Kicheon
2014-01-01
We address the question of the locality versus nonlocality in the Aharonov-Bohm and the Aharonov-Casher effects. For this purpose, we investigate all possible configurations of ideal shielding of the overlap between the electromagnetic fields generated by a charge and by a magnetic flux, and analyze their consequences on the Aharonov-Bohm-Casher interference. In a classical treatment of shielding, the Aharonov-Bohm-Casher effect vanishes regardless of the geometry of shielding, when the local...
Hidden superconformal symmetry of spinless Aharonov-Bohm system
Correa, Francisco; Falomir, Horacio; Jakubsky, Vit; Plyushchay, Mikhail S.
2009-01-01
A hidden supersymmetry is revealed in the spinless Aharonov-Bohm problem. The intrinsic supersymmetric structure is shown to be intimately related with the scale symmetry. As a result, a bosonized superconformal symmetry is identified in the system. Different self-adjoint extensions of the Aharonov-Bohm problem are studied in the light of this superconformal structure and interacting anyons. Scattering problem of the original Aharonov-Bohm model is discussed in the context of the revealed sup...
Photonic Aharonov–Bohm effect in photon–phonon interactions
Li, Enbang; Eggleton, Benjamin J; Fang, Kejie; Fan, Shanhui
2014-01-01
The Aharonov–Bohm effect is one of the most intriguing phenomena in both classical and quantum physics, and associates with a number of important and fundamental issues in quantum mechanics. The Aharonov–Bohm effects of charged particles have been experimentally demonstrated and found applications in various fields. Recently, attention has also focused on the Aharonov–Bohm effect for neutral particles, such as photons. Here we propose to utilize the photon–phonon interactions t...
Non-Abelian Vortices with an Aharonov-Bohm Effect
Evslin, Jarah; Nitta, Muneto; Ohashi, Keisuke; Vinci, Walter
2014-01-01
The interplay of gauge dynamics and flavor symmetries often leads to remarkably subtle phenomena in the presence of soliton configurations. Non-Abelian vortices -- vortex solutions with continuous internal orientational moduli -- provide an example. Here we study the effect of weakly gauging a U(1)_R subgroup of the flavor symmetry on such BPS vortex solutions. Our prototypical setting consists of an SU(2) x U(1) gauge theory with N_f=2 sets of fundamental scalars that break the gauge symmetry to an "electromagnetic" U(1). The weak U(1)_R gauging converts the well-known CP1 orientation modulus |B| of the non-Abelian vortex into a parameter characterizing the strength of the magnetic field that is responsible for the Aharonov-Bohm effect. As the phase of B remains a genuine zero mode while the electromagnetic gauge symmetry is Higgsed in the interior of the vortex, these solutions are superconducting strings.
Relativistic Aharonov endash Bohm endash Coulomb problem
International Nuclear Information System (INIS)
The ((2+1)-dimensional) Aharonov endash Bohm effect is analyzed for a spin-1/2 particle in the case that a 1/r potential is present. Scalar and vector couplings are each considered. It is found that the approach in which the flux tube is given a finite radius that is taken to zero only after a matching of boundary conditions does not give physically meaningful results. Specifically, the operations of taking the limit of zero flux tube radius and the Galilean limit do not commute. Thus there appears to be no satisfactory solution of the relativistic Aharonov endash Bohm endash Coulomb problem using the finite radius flux tube method. Copyright copyright 1996 Academic Press, Inc
Aharonov--Bohm problem for vector bosons
Castro, Luis B
2015-01-01
The Aharonov--Bohm (AB) problem for vector bosons by the Duffin--Kemmer--Petiau (DKP) formalism is analyzed. The relevant eigenvalue equation coming from the DKP formalism reveals an equivalence to the spin--$1/2$ AB problem. By using the self--adjoint extension approach, we examine the bound state scenario. The energy spectra are explicitly computed as well as their dependencies on the magnetic flux parameter and also the conditions for the occurrence of bound states.
Electromagnetic potentials and Aharonov-Bohm effect
Ershkovich, Alexander
2012-01-01
Hamilton-Jacobi equation which governs classical mechanics and electrodynamics explicitly depends on the electromagnetic potentials (A,{\\phi}), similar to Schroedinger equation. We derived the Aharonov-Bohm effect from Hamilton-Jacobi equation thereby having proved that this effect is of classical origin. These facts enable us to arrive at the following conclusions: a) the very idea of special role of potentials (A,{\\phi}) in quantum mechanics (different from their role in classical physics) ...
Aharonov-Bohm scattering on a cone
Alvarez, Marcos
1998-01-01
The Aharonov-Bohm scattering amplitude is calculated in the context of planar gravity with localized sources which also carry a magnetic flux. These sources cause space-time to develop conical singularities at their location, thus introducing novel effects in the scattering of electrically charged particles. The behaviour of the wave function in the proximity of the classical scattering directions is analyzed by means of an asymptotic expansion previously introduced by the author. It is found...
The untyped stack calculus and Bohm's theorem
Alberto Carraro
2013-01-01
The stack calculus is a functional language in which is in a Curry-Howard correspondence with classical logic. It enjoys confluence but, as well as Parigot's lambda-mu, does not admit the Bohm Theorem, typical of the lambda-calculus. We present a simple extension of stack calculus which is for the stack calculus what Saurin's Lambda-mu is for lambda-mu.
Grochol, M.; Grosse, F.; Zimmermann, R.
2006-09-01
The optical exciton Aharonov-Bohm effect—i.e., an oscillatory component in the energy of optically active (bright) states—is investigated in nanorings. It is shown that a small effective electron mass, strong confinement of the electron, and high barrier for the hole, achieved, e.g., by an InAs nanoring embedded in an AlGaSb quantum well, are favorable for observing the optical exciton Aharonov-Bohm effect. The second derivative of the exciton energy with respect to the magnetic field is utilized to extract Aharonov-Bohm oscillations even for the lowest bright state unambiguously. A connection between the theories for infinitesimal narrow and finite width rings is established. Furthermore, the magnetization is compared to the persistent current, which oscillates periodically with the magnetic field and confirms thus the nontrivial (connected) topology of the wave function in the nanoring.
(Semi)classical motion in fields of Aharonov-Bohm and Aharonov-Casher
Azimov, Ya. I.; Ryndin, R. M.
1997-01-01
Particle motion in the fields of Aharonov-Bohm and Aharonov-Casher is considered in framework of the classical theory to reveal conditions admitting duality of the two configurations. Important role of orientation of the magnetic dipole moment is demonstrated. Duality becomes totally destroyed by addition of electric dipole and/or higher multipole moments. Correspondence between quantum and classical considerations is also discussed.
Mesoscopic Persistent Currents, Aharonov-Bohm Magnetic Flux and Time Reversal Symmetry
Institute of Scientific and Technical Information of China (English)
LI Hua-Zhong
2003-01-01
We discuss the effect of Aharonov-Bohm magnetic flux on the time reversal symmetric properties of .mesoscopic metallic ring systems. It is usually believed that AB flux causes time reversal symmetry breaking. We analyse the case of mesoscopic persistent currents and find out that AB flux does not breai time reversal symmetry. Our arguments are supported by the general theory of mesoscopic persistent currents.
Time-dependent Pauli equation in the presence of the Aharonov-Bohm effect
International Nuclear Information System (INIS)
We use the Lewis-Riesenfeld theory to determine the exact form of the wavefunctions of a two-dimensional Pauli equation of a charged spin 1/2 particle with time-dependent mass and frequency in the presence of the Aharonov-Bohm effect and a two-dimensional time-dependent harmonic oscillator. We find that the irregular solution at the origin as well as the regular one contributes to the phase of the wavefunction
Time-dependent Pauli equation in the presence of the Aharonov-Bohm effect
Bouguerra, Y.; Bounames, A.; Maamache, M.; Saadi, Y.
2008-04-01
We use the Lewis-Riesenfeld theory to determine the exact form of the wavefunctions of a two-dimensional Pauli equation of a charged spin 1/2 particle with time-dependent mass and frequency in the presence of the Aharonov-Bohm effect and a two-dimensional time-dependent harmonic oscillator. We find that the irregular solution at the origin as well as the regular one contributes to the phase of the wavefunction.
Aharonov-Bohm Effect and the Supersymmetry of Identical Anyons
V. Jakubský
2010-01-01
We briefly review the relation between the Aharonov-Bohm effect and the dynamical realization of anyons. We show how the particular symmetries of the Aharonov-Bohm model give rise to the (nonlinear) supersymmetry of the two-body system of identical anyons.
Aharonov-Bohm oscillations in the local density of states
A. Cano; Paul, I
2009-01-01
The scattering of electrons with inhomogeneities produces modulations in the local density of states of a metal. We show that electron interference contributions to these modulations are affected by the magnetic field via the Aharonov-Bohm effect. This can be exploited in a simple STM setup that serves as an Aharonov-Bohm interferometer at the nanometer scale.
The Aharonov-Bohm effect in noncommutative quantum mechanics
International Nuclear Information System (INIS)
The Aharonov-Bohm effect in noncommutative (NC) quantum mechanics is studied. First, by introducing a shift for the magnetic vector potential we give the Schroedinger equations in the presence of a magnetic field on NC space and NC phase space, respectively. Then, by solving the Schroedinger equations, we obtain the Aharonov-Bohm phase on NC space and NC phase space, respectively. (orig.)
Propagator for an Aharonov-Bohm-Coulomb system
Park, D. K.; Yoo, Sahng-Kyoon; Lee, Soo-Young; Kahng, Jae-Rok; Park, Chang Soo; Yim, Eui-Soon; Lee, C.H.
1997-01-01
The propagator of three-dimensional Aharonov-Bohm-Coulomb system is calculated by following the Duru-Kleinert method. It is shown that the system is reduced to two independent two dimensional Aharonov-Bohm plus harmonic oscillator systems through dimensional extension and Kustaanheimo-Stiefel transformation. The energy spectrum is deduced.
Aharonov-Bohm Effect and the Supersymmetry of Identical Anyons
Directory of Open Access Journals (Sweden)
V. Jakubský
2010-01-01
Full Text Available We briefly review the relation between the Aharonov-Bohm effect and the dynamical realization of anyons. We show how the particular symmetries of the Aharonov-Bohm model give rise to the (nonlinear supersymmetry of the two-body system of identical anyons.
Optical Aharonov-Bohm effect: an inverse hyperbolic problems approach
Eskin, Gregory
2007-01-01
We describe the general setting for the optical Aharonov-Bohm effect based on the inverse problem of the identification of the coefficients of the governing hyperbolic equation by the boundary measurements. We interpret the inverse problem result as a possibility in principle to detect the optical Aharonov-Bohm effect by the boundary measurements.
Optical analogue of the Aharonov-Bohm effect using anisotropic media
International Nuclear Information System (INIS)
We show that in the context of paraxial optics, which can be analyzed through a wave equation similar to the non-relativistic Schroedinger equation of quantum mechanics but replacing time t by spatial coordinate z, the existence of a vector potential A-perpendicular mimicking the magnetic vector potential in quantum mechanics is allowed by specific gauge symmetries of the optical field in a medium with anisotropic refractive index. In this way, we use Feynman's path integral to demonstrate an optical analogue of the quantum-mechanical Aharonov-Bohm effect, encouraging the search for another optical systems with analogies with more complex quantum field theories. -- Highlights: → The optical analogue of the Aharonov-Bohm effect is demonstrated using anisotropic media. → It follows from the gauge principle applied to the optical field in the paraxial regime. → Feynman's path integral formalism is used to obtain the main result, leading directly from geometric to physical optics.
Aharonov-Bohm phase for an electromagnetic wave background
Bright, Max; Singleton, Douglas; Yoshida, Atsushi
2015-09-01
The canonical Aharonov-Bohm effect is usually studied with time-independent potentials. In this work, we investigate the Aharonov-Bohm phase acquired by a charged particle moving in time-dependent potentials. In particular, we focus on the case of a charged particle moving in the time-varying field of a plane electromagnetic wave. We work out the Aharonov-Bohm phase using both the potential (i.e. oint A_μ dx ^μ ) and the field (i.e. 1/2int F_{μ ν } dσ ^{μ ν }) forms of the Aharonov-Bohm phase. We give conditions in terms of the parameters of the system (frequency of the electromagnetic wave, the size of the space-time loop, amplitude of the electromagnetic wave) under which the time-varying Aharonov-Bohm effect could be observed.
Photonic Aharonov-Bohm effect in photon-phonon interactions.
Li, Enbang; Eggleton, Benjamin J; Fang, Kejie; Fan, Shanhui
2014-01-01
The Aharonov-Bohm effect is one of the most intriguing phenomena in both classical and quantum physics, and associates with a number of important and fundamental issues in quantum mechanics. The Aharonov-Bohm effects of charged particles have been experimentally demonstrated and found applications in various fields. Recently, attention has also focused on the Aharonov-Bohm effect for neutral particles, such as photons. Here we propose to utilize the photon-phonon interactions to demonstrate that photonic Aharonov-Bohm effects do exist for photons. By introducing nonreciprocal phases for photons, we observe experimentally a gauge potential for photons in the visible range based on the photon-phonon interactions in acousto-optic crystals, and demonstrate the photonic Aharonov-Bohm effect. The results presented here point to new possibilities to control and manipulate photons by designing an effective gauge potential. PMID:24476790
Photonic Aharonov–Bohm effect in photon–phonon interactions
Li, Enbang; Eggleton, Benjamin J.; Fang, Kejie; Fan, Shanhui
2014-01-01
The Aharonov–Bohm effect is one of the most intriguing phenomena in both classical and quantum physics, and associates with a number of important and fundamental issues in quantum mechanics. The Aharonov–Bohm effects of charged particles have been experimentally demonstrated and found applications in various fields. Recently, attention has also focused on the Aharonov–Bohm effect for neutral particles, such as photons. Here we propose to utilize the photon–phonon interactions to demonstrate that photonic Aharonov–Bohm effects do exist for photons. By introducing nonreciprocal phases for photons, we observe experimentally a gauge potential for photons in the visible range based on the photon–phonon interactions in acousto-optic crystals, and demonstrate the photonic Aharonov–Bohm effect. The results presented here point to new possibilities to control and manipulate photons by designing an effective gauge potential. PMID:24476790
Aharonov-Bohm phase for an electromagnetic wave background
International Nuclear Information System (INIS)
The canonical Aharonov-Bohm effect is usually studied with time-independent potentials. In this work, we investigate the Aharonov-Bohm phase acquired by a charged particle moving in time-dependent potentials. In particular, we focus on the case of a charged particle moving in the time-varying field of a plane electromagnetic wave. We work out the Aharonov-Bohm phase using both the potential (i.e. circular integral Aμ dxμ) and the field (i.e. (1)/(2) ∫ Fμνdσμν) forms of the Aharonov-Bohm phase. We give conditions in terms of the parameters of the system (frequency of the electromagnetic wave, the size of the space-time loop, amplitude of the electromagnetic wave) under which the time-varying Aharonov-Bohm effect could be observed. (orig.)
Aharonov-Bohm phase for an electromagnetic wave background
Energy Technology Data Exchange (ETDEWEB)
Bright, Max [California State University Fresno, Department of Physics, Fresno, CA (United States); Singleton, Douglas [California State University Fresno, Department of Physics, Fresno, CA (United States); UNESP-Univ. Estadual Paulista, ICTP South American Institute for Fundamental Research, Sao Paulo, SP (Brazil); Yoshida, Atsushi [University of Virginia, Department of Physics, Charlottesville, VA (United States); Hue University College of Education, Hue (Viet Nam)
2015-09-15
The canonical Aharonov-Bohm effect is usually studied with time-independent potentials. In this work, we investigate the Aharonov-Bohm phase acquired by a charged particle moving in time-dependent potentials. In particular, we focus on the case of a charged particle moving in the time-varying field of a plane electromagnetic wave. We work out the Aharonov-Bohm phase using both the potential (i.e. circular integral A{sub μ} dx{sup μ}) and the field (i.e. (1)/(2) ∫ F{sub μν}dσ{sup μν}) forms of the Aharonov-Bohm phase. We give conditions in terms of the parameters of the system (frequency of the electromagnetic wave, the size of the space-time loop, amplitude of the electromagnetic wave) under which the time-varying Aharonov-Bohm effect could be observed. (orig.)
Infinite potential the life and times of David Bohm
Peat, David
1997-01-01
Throughout his life, David Bohm felt himself to be different, and this was reflected in his lifestyle and in his physics. His life was one of unfulfilled searching. If one compares mainstream physics to the church, with a solid hierarchy of cardinals, archbishops and bishops, Bohm was an ascetic hermit who would occasionally come in from the wilderness with a compelling message, only to disappear again. Bohmian quantum mechanics is not part of mainstream physics, but for those who do cross over, like John Bell, the commitment can be rewarding. In the post-war 'Un-American Activities' purge, Bohm lost a prestigious job at Princeton and t emporarily his US citizenship, and his nomadic career took him to Brazil, Israel and Bristol before he finally settled in London's Birkbeck College. A sensitive-written book about a gifted, unusual and sometimes provocative figure. The interaction between Bohm and Oppenheimer is especially interesting, while Bohm's later life was bizarre.
Quantum Computation with Aharonov-Bohm Qubits
Barone, A.; Hakioglu, T.; Kulik, I. O.
2002-01-01
We analyze the posibility of employing the mesoscopic-nanoscopic ring of a normal metal in a doubly degenerate persistent current state with a third auxihilary level and in the presence of the Aharonov-Bohm flux equal to the half of the normal flux quantum $\\hbar c/e$ as a qubit. The auxiliary level can be effectively used for all fundamental quantum logic gate (qu-gate) operations which includes the initialization, phase rotation, bit flip and the Hadamard transformation as well as the doubl...
Aharonov–Bohm phase for an electromagnetic wave background
Bright, Max; Singleton, Douglas; Yoshida, Atsushi
2015-01-01
The canonical Aharonov-Bohm effect is usually studied with time-independent potentials. In this work, we investigate the Aharonov-Bohm phase acquired by a charged particle moving in {\\it time-dependent} potentials . In particular, we focus on the case of a charged particle moving in the time varying field of a plane electromagnetic wave. We work out the Aharonov-Bohm phase using both the potential ({\\it i.e.} $\\oint A_\\mu dx ^\\mu$) and field ({\\it i.e.} $\\frac{1}{2}\\int F_{\\mu \
Two-particle Aharonov-Bohm effect in electronic interferometers
International Nuclear Information System (INIS)
We review recent theoretical investigations on the two-particle Aharonov-Bohm effect and its relation to entanglement production and detection. The difficulties of the entanglement detection due to dephasing and finite temperature are discussed regarding a recent experimental realization of a two-particle Aharonov-Bohm interferometer [15]. We also discuss a theoretical proposal for a two-particle Aharonov-Bohm interferometer, which as against the finite bias setup is driven with dynamical single-electron sources allowing for the tunable production of time-bin entanglement.
The Aharonov-Bohm effect: Theoretical calculations and interpretations
International Nuclear Information System (INIS)
The Aharonov-Bohm effect - the action of an external inaccessible field on the quantum state of a charged particle - is investigated in detail. An exact expression is found for the scattering amplitude of the charged particle in an infinitely long solenoid and its behavior in the shadow region is investigated. The Aharonov-Bohm effect is investigated for bound states, including Landau levels in a uniform magnetic field. It is demonstrated that the Aharonov-Bohm effect arises during the switching-on process of an external magnetic field
Aharonov-Bohm phase for an electromagnetic wave background
Bright, Max; Yoshida, Atsushi
2015-01-01
The canonical Aharonov-Bohm effect is usually studied with time-independent potentials. In this work, we investigate the Aharonov-Bohm phase acquired by a charged particle moving in {\\it time-dependent} potentials . In particular, we focus on the case of a charged particle moving in the time varying field of a plane electromagnetic wave. We work out the Aharonov-Bohm phase using both the potential ({\\it i.e.} $\\oint A_\\mu dx ^\\mu$) and field ({\\it i.e.} $\\frac{1}{2}\\int F_{\\mu \
The Bohm criterion for a dusty plasma sheath
Indian Academy of Sciences (India)
B P Pandey; Anjan Dutta
2005-07-01
The formation of the sheath in a dusty plasma is investigated. The Bohm criterion is derived for two different cases: (a) when electrons are in thermodynamic equilibrium and dust grains provide the immobile, stationary background and (b) when both electrons and ions are in thermodynamic equilibrium and dust grains are moving. In the first case, Bohm criterion gets modified due to the fluctuation of the charge on the grain surface. In the second case, the collisional and Coulombic drag play important role in determining the Bohm criterion.
The Aharonov-Bohm Effect in the Momentum Space
Dragoman, D.; Bogdan, S.
2005-01-01
The Schrodinger formalism of quantum mechanics is used to demonstrate the existence of the Aharonov-Bohm effect in momentum space and set-ups for experimentally demonstrating it are proposed for either free or ballistic electrons.
New formulae for the Aharonov-Bohm wave operators
Richard, Serge
2008-01-01
It is proved that the wave operators corresponding to Schr¨odinger operators with Aharonov- Bohm type magnetic fields can be rewritten in terms of explicit functions of the generator of dilations and of the Laplacian.
Photonic Aharonov-Bohm effect based on dynamic modulation.
Fang, Kejie; Yu, Zongfu; Fan, Shanhui
2012-04-13
We show that when the refractive index of a photonic system is harmonically modulated, the phase of the modulation introduces an effective gauge potential for photons. This effective gauge potential can be used to create a photonic Aharonov-Bohm effect. We show that the photonic Aharonov-Bohm effect provides the optimal mechanism for achieving complete on-chip nonmagnetic optical isolation. PMID:22587255
Unitarity of the Aharonov-Bohm Scattering Amplitudes
Arai, Masato; Minakata, Hisakazu
1996-01-01
We discuss the unitarity relation of the Aharonov-Bohm scattering amplitude with the hope that it distinguishes between the differing treatments which employ different incident waves. We find that the original Aharonov-Bohm scattering amplitude satisfies the unitarity relation under the regularization prescription whose theoretical foundation does not appear to be understood. On the other hand, the amplitude obtained by Ruijsenaars who uses plane wave as incident wave also satisfies the unita...
Aharonov-Casher and scalar Aharonov-Bohm topological effects.
Dulat, Sayipjamal; Ma, Kai
2012-02-17
We reexamine the topological and nonlocal natures of the Aharonov-Casher and scalar Aharonov-Bohm phase effects. The underlying U(1) gauge structure is exhibited explicitly. And the conditions for developing topological Aharonov-Casher and scalar Aharonov-Bohm phases are clarified. We analyze the arguments of M. Peshkin and H. J. Lipkin [Phys. Rev. Lett. 74, 2847 (1995)] in detail and show that they are based on the wrong Hamiltonian which yields their conclusion incorrect. PMID:22401183
The Aharonov-Bohm Effect in Noncommutative Quantum Mechanics
Li, Kang; Dulat, Sayipjamal
2005-01-01
The Aharonov-Bohm (AB) effect in non-commutative quantum mechanics (NCQM) is studied. First, by introducing a shift for the magnetic vector potential we give the Schr$\\ddot{o}$dinger equations in the presence of a magnetic field on NC space and NC phase space, respectively. Then by solving the Schr$\\ddot{o}$dinger equations, we obtain the Aharonov-Bohm (AB) phase on NC space and NC phase space, respectively.
Aharonov-Bohm oscillations of a tunable quantum ring
Keyser, U.F; Borck, S.; Haug, R. J.; Wegscheider, W.; Bichler, M.; Abstreiter, G.
2002-01-01
With an atomic force microscope a ring geometry with self-aligned in-plane gates was directly written into a GaAs/AlGaAs-heterostructure. Transport measurements in the open regime show only one transmitting mode and Aharonov-Bohm oscillations with more than 50% modulation are observed in the conductance. The tuning via in-plane gates allows to study the Aharonov-Bohm effect in the whole range from the open ring to the Coulomb-blockade regime.
Quantum interference and Aharonov-Bohm oscillations in topological insulators.
Bardarson, Jens H; Moore, Joel E
2013-05-01
Topological insulators (TIs) have an insulating bulk but a metallic surface. In the simplest case, the surface electronic structure of a three-dimensional (3D) TI is described by a single two-dimensional (2D) Dirac cone. A single 2D Dirac fermion cannot be realized in an isolated 2D system with time-reversal symmetry, but rather owes its existence to the topological properties of the 3D bulk wavefunctions. The transport properties of such a surface state are of considerable current interest; they have some similarities with graphene, which also realizes Dirac fermions, but have several unique features in their response to magnetic fields. In this review we give an overview of some of the main quantum transport properties of TI surfaces. We focus on the efforts to use quantum interference phenomena, such as weak anti-localization and the Aharonov-Bohm effect, to verify in a transport experiment the Dirac nature of the surface state and its defining properties. In addition to explaining the basic ideas and predictions of the theory, we provide a survey of recent experimental work. PMID:23552181
Quantum interference and Aharonov–Bohm oscillations in topological insulators
International Nuclear Information System (INIS)
Topological insulators (TIs) have an insulating bulk but a metallic surface. In the simplest case, the surface electronic structure of a three-dimensional (3D) TI is described by a single two-dimensional (2D) Dirac cone. A single 2D Dirac fermion cannot be realized in an isolated 2D system with time-reversal symmetry, but rather owes its existence to the topological properties of the 3D bulk wavefunctions. The transport properties of such a surface state are of considerable current interest; they have some similarities with graphene, which also realizes Dirac fermions, but have several unique features in their response to magnetic fields. In this review we give an overview of some of the main quantum transport properties of TI surfaces. We focus on the efforts to use quantum interference phenomena, such as weak anti-localization and the Aharonov–Bohm effect, to verify in a transport experiment the Dirac nature of the surface state and its defining properties. In addition to explaining the basic ideas and predictions of the theory, we provide a survey of recent experimental work. (review article)
Non-Abelian vortices with an Aharonov-Bohm effect
Energy Technology Data Exchange (ETDEWEB)
Evslin, Jarah [TPCSF, IHEP, Chinese Academy of Sciences,Beijing (China); Theoretical physics division, IHEP, Chinese Academy of Sciences,Beijing (China); Konishi, Kenichi [Department of Physics “Enrico Fermi”, University of Pisa,Largo Pontecorvo 3, 56127, Pisa (Italy); INFN, Sezione di Pisa,Largo Pontecorvo 3, 56127, Pisa (Italy); Nitta, Muneto [Department of Physics, and Research and Education Center for Natural Sciences, Keio University,4-1-1 Hiyoshi, Yokohama, Kanagawa 223-8521 (Japan); Ohashi, Keisuke [Department of Physics, Osaka City University,Osaka (Japan); Vinci, Walter [London Centre for Nanotechnology and Computer Science, University College London,17-19 Gordon Street, London, WC1H 0AH (United Kingdom)
2014-01-16
The interplay of gauge dynamics and flavor symmetries often leads to remarkably subtle phenomena in the presence of soliton configurations. Non-Abelian vortices — vortex solutions with continuous internal orientational moduli — provide an example. Here we study the effect of weakly gauging a U(1){sub R} subgroup of the flavor symmetry on such BPS vortex solutions. Our prototypical setting consists of an SU(2)×U(1) gauge theory with N{sub f}=2 sets of fundamental scalars that break the gauge symmetry to an “electromagnetic' U(1). The weak U(1){sub R} gauging converts the well-known CP{sup 1} orientation modulus |B| of the non-Abelian vortex into a parameter characterizing the strength of the magnetic field that is responsible for the Aharonov-Bohm effect. As the phase of B remains a genuine zero mode while the electromagnetic gauge symmetry is Higgsed in the interior of the vortex, these solutions are superconducting strings.
International Nuclear Information System (INIS)
We theoretically investigated the dephasing in an Aharonov-Bohm interferometer containing a lateral double quantum dot induced by coupling with a quantum dot charge sensor. We employed the interpolative second-order perturbation theory to include the charge sensing Coulomb interaction. It is shown that the visibility of the Aharonov-Bohm oscillation of the linear conductance decreases monotonically as the sensing Coulomb interaction increases. In particular, for a weak sensing interaction regime, the visibility decreases parabolically, and it behaves linearly for a strong sensing interaction regime.
Instanton Aharonov-Bohm effect and macroscopic quantum coherence in charge-density-wave systems
International Nuclear Information System (INIS)
It is predicted that in a charge-density-wave (CDW) ring-shaped conductor, placed in an external vector-potential field, there should appear a new Aharonov-Bohm contribution to the magnetic susceptibility and the electrical conductivity oscillating as a function of the flux with the period φ0=hc/2e. This contribution arises from instanton transitions between degenerate vacua of the CDW-condensate and is the solid-state realization of θ-vacuum in the quantum field theory. The period transforms into φ0/N in N strongly correlated parallel CDW chains. (author). 27 refs, 2 figs
Spin-dependent Bohm trajectories for Pauli and Dirac eigenstates of hydrogen
Colijn, C.; Vrscay, E. R.
2003-01-01
The de Broglie-Bohm causal theory of quantum mechanics is applied to the hydrogen atom in the fully spin-dependent and relativistic framework of the Dirac equation, and in the nonrelativistic but spin-dependent framework of the Pauli equation. Eigenstates are chosen which are simultaneous eigenstates of the energy H, total angular momentum M, and z component of the total angular momentum M_z. We find the trajectories of the electron, and show that in these eigenstates, motion is circular abou...
Boyer, Timothy H
2014-01-01
A new classical electromagnetic analysis is presented suggesting that the Aharonov-Bohm phase shift is overwhelmingly likely to arise from a classical lag effect based upon classical electromagnetic forces. The analysis makes use of several aspects of classical electromagnetic theory which are unfamiliar to most physicists, including the Darwin Lagrangian, acceleration-based electric fields, internal electromagnetic momentum in a magnet, and a magnet model involving at least three mutually-interacting particles. Only when the acceleration-based electric forces acting on the passing charge are included do we find consistency with all the relativistic conservation laws: energy, linear momentum, angular momentum, and constant center-of-mass velocity. The electric forces on the passing charge lead to a lag effect which accounts quantitatively for the Aharonov-Bohm phase shift. Thus the classical analysis strongly suggests that the Aharonov-Bohm phase shift (observed when electrons pass a long solenoid which corre...
Aharonov-Bohm effect in optical activity
International Nuclear Information System (INIS)
Optically active media have the helical and dissymmetric crystal structure, which constrains the motions of the electrons to a helical path under the influence of the incident electric field. The charge flow along the helices induces a magnetic field in the direction of the axis of helices. The helical structure hence acts as natural micro-solenoids for the electromagnetic waves passing through them. Optical rotation is related to the difference in the accumulative Aharonov-Bohm (AB) phase between the right- and the left-circularly polarized waves. The AB phase is proportional to the angular momentum of an electron moving around the micro-solenoid. Originally the AB phase is shown to be a continuous function of the magnetic flux. However, quantization of the geometrical angular momentum leads to the quantized AB phase. The rotatory power and the Verdet constant are proportional to the refractive index of the medium. The quantized current in the micro-solenoid is proportional to the Bohr magneton and inversely proportional to the area of the helices.
Aharonov endash Bohm oscillations at finite temperature
International Nuclear Information System (INIS)
The Aharonov endash Bohm effect is the quantum interference of charged particles in mesoscopic rings enclosing a magnetic field. The wavefunction acquires a phase due to the field flux φ and gives rise to flux-dependent oscillations in persistent charge currents. The period and amplitude of the oscillations are associated with the properties of the Fermi surface of the elementary excitations. For systems with one Fermi surface the groundstate persistent current has the form of a saw-tooth. The temperature reduces the amplitudes of oscillation by smearing the Fermi surface. The amplitude of higher harmonics decreases faster with T than the fundamental one, changing the saw-tooth to a more sinusoidal form with much smaller amplitude. The controlling parameter is LT/zvF, where L is the length of the ring, vF is the Fermi velocity and z the dressed generalized charge. Our calculations are performed within the framework of Bethe close-quote s ansatz. copyright 1996 American Institute of Physics
The limits of the Bohm criterion in collisional plasmas
International Nuclear Information System (INIS)
The sheath formation within a low-pressure collisional plasma is analysed by means of a two-fluid model. The Bohm criterion takes into account the effects of the electric field and the inertia of the ions. Numerical results yield that these effects contribute to the space charge formation, only, if the collisionality is lower than a relatively small threshold. It follows that a lower and an upper limit of the drift speed of the ions exist where the effects treated by Bohm can form a sheath. This interval becomes narrower as the collisionality increases and vanishes at the mentioned threshold. Above the threshold, the sheath is mainly created by collisions and the ionisation. Under these conditions, the sheath formation cannot be described by means of Bohm like criteria. In a few references, a so-called upper limit of the Bohm criterion is stated for collisional plasmas where the momentum equation of the ions is taken into account, only. However, the present paper shows that this limit results in an unrealistically steep increase of the space charge density towards the wall, and, therefore, it yields no useful limit of the Bohm velocity
Gravitational and Aharonov-Bohm phases in neutron interferometry
International Nuclear Information System (INIS)
This thesis describes two experiments with the interferometer for very-cold-neutrons (VCN) at the Institut Laue-Langevin in Grenoble, France. This interferometer operates with neutrons that are 40 m/s slow and uses micro-fabricated phase gratings as beam-splitters. The first experiment is a demonstration of the scalar neutron Aharonov-Bohm (AB) effect, which is the neutron analogue of the electrostatic AB effect for electrons. Aharonov and Bohm (1959) proposed this latter effect together with the magnetic AB effect to clarify the significance of electromagnetic potentials in quantum mechanics. The experiment described here focuses at for the first time simultaneously demonstrating the two essential operational signatures of all AB-type effects: their nondispersivity, i.e. wavelength independence, and the fact that they are not locally observable in a simply connected space-time. In this thesis it will be shown, as was already pointed out by Zeilinger (1984, 1986), that the neutron analogue also has both signatures and thus can be used to demonstrate them. In the experiment the paths of the neutron interferometer are enclosed by two anti-parallel solenoids. When, determined by a chopper, the neutron is completely inside the homogeneous field region of the coils the field is turned on and off, resulting in a phase shift due to the difference in magnetic energy. High-visibility fringes were observed even for phase shifts exceeding the limit given by the coherence length, which is a clear demonstration of the wavelength independence of this effect. Because the interferometer has spatially separated beams and uses unpolarized neutrons the effect of the magnetic field on the neutron is not locally observable in either of the interferometer arms. The second experiment is what is commonly known as a COW-experiment. In these experiments a neutron interferometer is tilted around its optical axis, resulting in a phase shift due to the difference in gravitational potential
Characterisation of ferromagnetic rings for Zernike phase plates using the Aharonov–Bohm effect
International Nuclear Information System (INIS)
Holographic measurements on magnetised thin-film cobalt rings have demonstrated both onion and vortex states of magnetisation. For a ring in the vortex state, the difference between phases of electron paths that pass through the ring and those that travel outside it was found to agree very well with Aharonov–Bohm theory within measurement error. Thus the magnetic flux in thin-film rings of ferromagnetic material can provide the phase shift required for phase plates in transmission electron microscopy. When a ring of this type is used as a phase plate, scattered electrons will be intercepted over a radial range similar to the ring width. A cobalt ring of thickness 20 nm can produce a phase difference of π/2 from a width of just under 30 nm, suggesting that the range of radial interception for this type of phase plate can be correspondingly small. -- Highlights: ► Thin-film rings of cobalt were magnetised and examined holographically. ► Both onion and vortex states of magnetisation were obtained, depending on ring width. ► Vortex phase shift agreed with Aharonov–Bohm theory within measurement error. ► For a ring used as phase plate, the radial range of interception may be as small as 30 nm.
The covariant, time-dependent Aharonov–Bohm effect
International Nuclear Information System (INIS)
We discuss two possible covariant generalizations of the Aharonov–Bohm effect – one expression in terms of the space–time line integral of the four-vector potential and the other expression in terms of the space–time “area” integral of the electric and magnetic fields written in terms of the Faraday 2-form. These expressions allow one to calculate the Aharonov–Bohm effect for time-dependent situations. In particular, we use these expressions to study the case of an infinite solenoid with a time varying flux and find that the phase shift is zero due to a cancellation of the Aharonov–Bohm phase shift with a phase shift coming from the Lorentz force associated with the electric field, E=−∂tA, outside the solenoid. This result may already have been confirmed experimentally
The covariant, time-dependent Aharonov–Bohm effect
Energy Technology Data Exchange (ETDEWEB)
Singleton, Douglas, E-mail: dougs@csufresno.edu [Physics Department, CSU Fresno, Fresno, CA 93740-8031 (United States); Department of Physics, Institut Teknologi Bandung, Bandung (Indonesia); Vagenas, Elias C., E-mail: evagenas@academyofathens.gr [Research Center for Astronomy and Applied Mathematics, Academy of Athens, Soranou Efessiou 4, GR-11527, Athens (Greece)
2013-06-10
We discuss two possible covariant generalizations of the Aharonov–Bohm effect – one expression in terms of the space–time line integral of the four-vector potential and the other expression in terms of the space–time “area” integral of the electric and magnetic fields written in terms of the Faraday 2-form. These expressions allow one to calculate the Aharonov–Bohm effect for time-dependent situations. In particular, we use these expressions to study the case of an infinite solenoid with a time varying flux and find that the phase shift is zero due to a cancellation of the Aharonov–Bohm phase shift with a phase shift coming from the Lorentz force associated with the electric field, E=−∂{sub t}A, outside the solenoid. This result may already have been confirmed experimentally.
The covariant, time-dependent Aharonov-Bohm Effect
Singleton, Douglas
2013-01-01
We discuss two possible covariant generalizations of the Aharonov-Bohm effect - one expression in terms of the space-time line integral of the four-vector potential and the other expression in terms of the space-time "area" integral of the electric and magnetic fields written in terms of the Faraday 2-form. These expressions allow one to calculate the Aharonov-Bohm effect for time-dependent situations. In particular, we use these expressions to study the case of an infinite solenoid with a time varying flux and find that the phase shift is zero due to a cancellation of the Aharonov-Bohm phase shift with a phase shift coming from the Lorentz force associated with the electric field, ${\\bf E} = - \\partial_t {\\bf A}$, outside the solenoid. This result may already have been confirmed experimentally.
The Bohm sheath criterion in strongly coupled complex plasmas
International Nuclear Information System (INIS)
A modification of the classical Bohm sheath criterion is investigated in complex plasmas containing Boltzmann electrons, cold fluid ions and strongly coupled microparticles. Equilibrium is provided by an effective 'temperature' associated with electrostatic interactions between charged grains. Using the small-potential expansion approach of the Sagdeev potential, a significant reduction of the ion Bohm velocity is obtained for complex plasma parameters relevant for experiments. The result is of consequence for all problems involving ion drag on microparticles, including parametric instability, structure formation, wave propagation, etc.
The Early History of the Aharonov-Bohm Effect
Hiley, B J
2013-01-01
This paper traces the early history of the Aharonov-Bohm effect. It appears to have been `discovered' at least three times to my knowledge before the defining paper of Aharonov and Bohm appeared in 1959. The first hint of the effect appears in Germany in 1939, immediately disappearing from sight in those troubled times. It reappeared in a paper in 1949, ten years before the defining paper appeared. Here I report the background to the early evolution of this effect, presenting first hand unpublished accounts reported to me by colleagues at Birkbeck College in the University of London.
Effect of Aharonov-Bohm Phase on Spin Tunneling
Park, ChangSoo; Park, D. K.
1999-01-01
The role of Aharonov-Bohm effect in quantum tunneling is examined when a potential is defined on the $S^1$ and has $N$-fold symmetry. We show that the low-lying energy levels split from the $N$-fold degenerate ground state oscillate as a function of the Aharonov-Bohm phase, from which general degeneracy conditions depending on the magnetic flux is obtained. We apply these results to the spin tunneling in a spin system with $N$-fold rotational symmetry around a hard axis.
Holonomy, Aharonov-Bohm effect and phonon scattering in superfluids
Furtado, Claudio; Carvalho, A. M. de M.; de Andrade, L. C. Garcia; Moraes, F.
2004-01-01
In this article we discuss the analogy between superfluids and a spinning thick cosmic string. We use the geometrical approach to obtain the geometrical phases for a phonon in the presence of a vortex. We use loop variables for a geometric description of Aharonov-Bohm effect in these systems. We use holonomy transformations to characterize globally the "space-time" of a vortex and in this point of view we study the gravitational analog of the Aharonov-Bohm effect in this system. We demonstrat...
Relativistic Aharonov--Bohm effect in the presence of two-dimensional Coulomb potential
Khalilov, Vladislav
2004-01-01
We obtain exact solutions to the Dirac equation and the relevant binding energies in the combined Aharonov--Bohm--Coulomb potential in 2+1 dimensions. By means of solutions obtained the quantum Aharonov--Bohm effect is studied for free and bound electron states. We show that the total scattering amplitude in the combined Aharonov--Bohm--Coulomb potential is a sum of the Aharonov--Bohm and the Coulomb scattering amplitudes. This modifies expression for the standard Aharonov--Bohm cross section...
Magnus Force and Aharonov-Bohm Effect in Superfluids
Sonin, E. B.
2001-01-01
The paper addresses the problem of the transverse force (Magnus force) on a vortex in a Galilean invariant quantum Bose liquid. Interaction of quasiparticles (phonons) with a vortex produces an additional transverse force (Iordanskii force). The Iordanskii force is related to the acoustic Aharonov--Bohm effect.Connection of the effective Magnus force with the Berry phase is also discussed.
Aharonov-Bohm oscillations in singly connected disordered conductors.
Aleiner, I L; Andreev, A V; Vinokur, V
2015-02-20
We show that the transport and thermodynamic properties of a singly connected disordered conductor exhibit quantum Aharonov-Bohm oscillations as a function of the total magnetic flux through the sample. The oscillations are associated with the interference contribution from a special class of electron trajectories confined to the surface of the sample. PMID:25763968
Aharonov-Bohm Phase in High Density Quark Matter
Chatterjee, Chandrasekar
2015-01-01
Stable non-Abelian vortices, that are color magnetic flux tubes as well as superfluid vortices, are present in the color-flavor locked (CFL) phase of dense quark matter with di-quark condensations. We calculate the Aharanov-Bohm phases of charged particles, that is, electrons, muons and CFL mesons made of tetra quarks around a non-Abelian vortex.
Group-theoretical derivation of Aharonov-Bohm phase shifts
Energy Technology Data Exchange (ETDEWEB)
Hagen, C. R. [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627-0171 (United States)
2013-02-15
The phase shifts of the Aharonov-Bohm effect are generally determined by means of the partial wave decomposition of the underlying Schroedinger equation. It is shown here that they readily emerge from an o(2,1) calculation of the energy levels employing an added harmonic oscillator potential which discretizes the spectrum.
Putting a Spin on the Aharonov-Bohm Oscillations
Anandan, Jeeva
2002-01-01
An experiment that shows the modulation of the Aharonov-Bohm oscillations of magneto-resistance in a mesoscopic ring is described. Possible theoretical explanations of this modulation due to the interaction of the electron spin with the magnetic and electric fields are considered.
Aharonov-Bohm phase in high density quark matter
Chatterjee, Chandrasekhar; Nitta, Muneto
2016-03-01
Stable non-Abelian vortices, which are color magnetic flux tubes as well as superfluid vortices, are present in the color-flavor locked phase of dense quark matter with diquark condensations. We calculate the Aharanov-Bohm phases of charged particles, that is, electrons, muons, and color-flavor locked mesons made of tetraquarks around a non-Abelian vortex.
Bohm's "quantum potential" can be considered falsified by experiment
Suarez, Antoine
2014-01-01
A Michelson-Morley-type experiment is described, which exploits two-photon interference between entangled photons instead of classical light interference. In this experimental context, the negative result (no shift in the detection rates) rules out David Bohm's postulate of an infinite-speed time-ordered "quantum potential", and thereby upholds the timeless standard quantum collapse.
Bohm, David
1951-01-01
This superb text by David Bohm, formerly Princeton University and Emeritus Professor of Theoretical Physics at Birkbeck College, University of London, provides a formulation of the quantum theory in terms of qualitative and imaginative concepts that have evolved outside and beyond classical theory. Although it presents the main ideas of quantum theory essentially in nonmathematical terms, it follows these with a broad range of specific applications that are worked out in considerable mathematical detail. Addressed primarily to advanced undergraduate students, the text begins with a study of t
Exner, Pavel; Stovicek, Pavel; Vytras, Petr
2001-01-01
The most general admissible boundary conditions are derived for an idealised Aharonov-Bohm flux intersecting the plane at the origin on the background of a homogeneous magnetic field. A standard technique based on self-adjoint extensions yields a four-parameter family of boundary conditions; other two parameters of the model are the Aharonov-Bohm flux and the homogeneous magnetic field. The generalised boundary conditions may be regarded as a combination of the Aharonov-Bohm effect with a poi...
Characterisation of ferromagnetic rings for Zernike phase plates using the Aharonov-Bohm effect.
Edgcombe, C J; Ionescu, A; Loudon, J C; Blackburn, A M; Kurebayashi, H; Barnes, C H W
2012-09-01
Holographic measurements on magnetised thin-film cobalt rings have demonstrated both onion and vortex states of magnetisation. For a ring in the vortex state, the difference between phases of electron paths that pass through the ring and those that travel outside it was found to agree very well with Aharonov-Bohm theory within measurement error. Thus the magnetic flux in thin-film rings of ferromagnetic material can provide the phase shift required for phase plates in transmission electron microscopy. When a ring of this type is used as a phase plate, scattered electrons will be intercepted over a radial range similar to the ring width. A cobalt ring of thickness 20 nm can produce a phase difference of π/2 from a width of just under 30 nm, suggesting that the range of radial interception for this type of phase plate can be correspondingly small. PMID:22842114
Spin-dependent Bohm trajectories for Pauli and Dirac eigenstates of hydrogen
Colijn, C
2002-01-01
The de Broglie-Bohm causal theory of quantum mechanics is applied to the hydrogen atom in the fully spin-dependent and relativistic framework of the Dirac equation, and in the nonrelativistic but spin-dependent framework of the Pauli equation. Eigenstates are chosen which are simultaneous eigenstates of the energy H, total angular momentum M, and z component of the total angular momentum M_z. We find the trajectories of the electron, and show that in these eigenstates, motion is circular about the z-axis, with constant angular velocity. We compute the rates of revolution for the ground (n=1) state and the n=2 states, and show that there is agreement in the relevant cases between the Dirac and Pauli results, and with earlier results on the Schrodinger equation.
Scalar Aharonov-Bohm effect with longitudinally polarized neutrons
International Nuclear Information System (INIS)
In the scalar Aharonov-Bohm effect, a charged particle (electron) interacts with the scalar electrostatic potential U in the field-free (i.e., force-free) region inside an electrostatic cylinder (Faraday cage). Using a perfect single-crystal neutron interferometer we have performed a ''dual'' scalar Aharonov-Bohm experiment by subjecting polarized thermal neutrons to a pulsed magnetic field. The pulsed magnetic field was spatially uniform, precluding any force on the neutrons. Aligning the direction of the pulsed magnetic field to the neutron magnetic moment also rules out any classical torque acting to change the neutron polarization. The observed phase shift is purely quantum mechanical in origin. A detailed description of the experiment, performed at the University of Missouri Research Reactor, and its interpretation is given in this paper. (c) 1999 The American Physical Society
Observation of Aharonov-Bohm effects by neutron interferometry
International Nuclear Information System (INIS)
The special and unique techniques of neutron interferometry have been used to observe a number of topological effects. These include the quantum mechanical phase shift of a neutron due to the Earth's rotation (the quantum analog of the Michelson-Gale-Pearson experiment with light), the phase shift of a particle carrying a magnetic moment (a neutron) encircling a line charge (the Aharonov-Casher effect) and the scalar Aharonov-Bohm effect, observed with a pulsed magnetic field solenoid and time-of-flight neutron detection. On the occasion of the 50th anniversary of the Aharonov-Bohm paper, we provide an overview of the neutron interferometry technique and a description of these three historic experiments.
Spin- and localization-induced fractional Aharonov-Bohm effect
Emperador, A.; Pederiva, F.; Lipparini, E.
2003-09-01
We performed a theoretical analysis of the Aharonov-Bohm oscillations of the ground-state energy of quasi-one-dimensional quantum rings in a magnetic field, recently observed in conductance experiments, by means of quantum Monte Carlo calculations. The model rings considered contain N=10 and N=4 electrons, with radii of 20 and 120 nm, respectively. These parameters give a close description of the nanorings analyzed in the experiments. In particular, the two cases well reproduce the high- and low-electron-density regimes. For N=10, we have found fractional Aharonov-Bohm effect with a period Φ0/2 due to the changes in the total spin of the ground state. For N=4, we have found fractional oscillations with a period Φ0/4, which are shown to be a consequence of strong localization.
On the computer simulation of the EPR-Bohm experiment
International Nuclear Information System (INIS)
We argue that supraluminal correlation without supraluminal signaling is a necessary consequence of any finite and discrete model for physics. Every day, the commercial and military practice of using encrypted communication based on correlated, pseudo-random signals illustrates this possibility. All that is needed are two levels of computational complexity which preclude using a smaller system to detect departures from ''randomness'' in the larger system. Hence the experimental realizations of the EPR-Bohm experiment leave open the question of whether the world of experience is ''random'' or pseudo-random. The latter possibility could be demonstrated experimentally if a complexity parameter related to the arm length and switching time in an Aspect-type realization of the EPR-Bohm experiment is sufficiently small compared to the number of reliable total counts which can be obtained in practice. 6 refs
Aharonov-Bohm Effect in Cyclotron and Synchrotron Radiations
Bagrov, V G; Levin, A; Tlyachev, V B
2000-01-01
We study the impact of Aharonov-Bohm solenoid on the radiation of a charged particle moving in a constant uniform magnetic field. With this aim in view, exact solutions of Klein-Gordon and Dirac equations are found in the magnetic-solenoid field. Using such solutions, we calculate exactly all the characteristics of one-photon spontaneous radiation both for spinless and spinning particle. Considering non-relativistic and relativistic approximations, we analyze cyclotron and synchrotron radiations in detail. Radiation peculiarities caused by the presence of the solenoid may be considered as a manifestation of Aharonov-Bohm effect in the radiation. In particular, it is shown that new spectral lines appear in the radiation spectrum. Due to angular distribution peculiarities of the radiation intensity, these lines can in principle be isolated from basic cyclotron and synchrotron radiation spectra
David Bohm la physique de l'infini
Teodorani, Massimo
2014-01-01
Les idées de David Bohm, indépendamment du scepticisme de ses collègues les plus traditionalistes, ont profondément influencé la physique du siècle dernier et ouvert une porte à la physique du nouveau millénaire. Grâce aussi aux contacts qu'il sut nouer avec des chercheurs d'autres branches du savoir, ses idées ont été accueillies avec beaucoup d'enthousiasme par les neuroscientifiques, les philosophes, les théologiens, les psychologues, les sociologues, les poètes, les artistes et les éducateurs. David Bohm avait peut-être pressenti qu'il existe une "physique de l'âme" et avec elle il voulait tracer un nouveau chemin pour une humanité à la dérive.
Electron transport through an Aharonov-Bohm ring with a side-coupled quantum dot
International Nuclear Information System (INIS)
We present a theoretical description for electron transport through an Aharonov-Bohm ring with a quantum dot side-coupled to one arm. An analytic formula of conductance is derived which shows the Aharonov-Bohm oscillations. The quantum dot modulates electron transmission through the coupled arm, and thus affects the amplitude of the AB oscillations. Tuning the plunger gate of the quantum dot can induce the antiresonance, in which the transmission through the coupled arm is quenched and the Aharonov-Bohm oscillations are suppressed completely. The temperature-dependence of the suppression of the Aharonov-Bohm oscillations is discussed
Aharonov-Bohm effect induced by circularly polarized light
Sigurdsson, H.; Kibis, O. V.; Shelykh, I. A.
2015-11-01
We demonstrated theoretically that the strong electron interaction with circularly polarized photons in ring-like nanostructures changes the phase of electron wave. This optically-induced effect is caused by the breaking of time-reversal symmetry and is similar to the Aharonov-Bohm effect. As a consequence of this phenomenon, the conductance of mesoscopic rings irradiated by a circularly polarized electromagnetic wave behaves as an oscillating function of the intensity and frequency of the wave.
Pauli criterion and the vector Aharonov endash Bohm effect
International Nuclear Information System (INIS)
After discussing the commutation relations of the kinetic angular momentum of the electron in the vector Aharonov endash Bohm effect, the author shows that the Pauli criterion for admissibility of the wave function is inapplicable. The point is that the kinetic angular momentum does not satisfy the fundamental commutation relations of the angular momentum. The inapplicability of the Pauli criterion reflects the breakdown of the symmetry of the electron close-quote s motion around the solenoid. Copyright copyright 1996 Academic Press, Inc
Realization of adiabatic Aharonov-Bohm scattering with neutrons
Sjöqvist, Erik; Almquist, Martin; Mattsson, Ken; Gürkan, Zeynep Nilhan; Hessmo, Björn
2015-11-01
The adiabatic Aharonov-Bohm (AB) effect is a manifestation of the Berry phase acquired when some slow variables take a planar spin around a loop. While the effect has been observed in molecular spectroscopy, direct measurement of the topological phase shift in a scattering experiment has been elusive in the past. Here, we demonstrate an adiabatic AB effect by explicit simulation of the dynamics of unpolarized very slow neutrons that scatter on a long straight current-carrying wire.
Magnetic edge states in Aharonov-Bohm graphene quantum rings
Farghadan, R.; Saffarzadeh, A.; Semiromi, E. Heidari
2014-01-01
The effect of electron-electron interaction on the electronic structure of Aharonov-Bohm (AB) graphene quantum rings (GQRs) is explored theoretically using the single-band tight-binding Hamiltonian and the mean-field Hubbard model. The electronic states and magnetic properties of hexagonal, triangular and circular GQRs with different sizes and zigzag edge terminations are studied. The results show that, although the AB oscillations in the all types of nanoring are affected by the interaction,...
Noncommutative analogue Aharonov-Bohm effect and superresonance
M.A. Anacleto; Brito, F. A.; E. Passos
2012-01-01
We consider the idea of modeling a rotating acoustic black hole by an idealized draining bathtub vortex which is a planar circulating flow phenomenon with a sink at the origin. We find the acoustic metric for this phenomenon from a noncommutative Abelian Higgs model. As such the acoustic metric not only describes a rotating acoustic black hole but also inherits the noncommutative characteristic of the spacetime. We address the issues of superresonance and analogue Aharonov-Bohm (AB) effect in...
Aaronov-Bohm effect for compound particles and collective excitations
Chaplik, A V
2002-01-01
The review of devoted to considering nonstandard versions of the magnetointerference effect (the Aaronov-Bohm effect). The dependence of the excitons energy in the unidimensional quantum ring on the magnetic field is studied with an account of the ring finite width. The behavior of the magnetoexcitons in the quantum-ring with the electron and hole separation is studied. The plasma oscillations in the nanotubes are considered and the formula for the plasmon frequency in dependence on the magnetic flow is obtained
The Fano Effect in Aharonov-Bohm interferometers
Entin-Wohlman, O.; Aharony, A.; Imry, Y.; Levinson, Y.
2001-01-01
After briefly reviewing the Fano effect, we explain why it may be relevant to various types of Aharonov-Bohm interferometers. We discuss both closed (electron conserving) and open interferometers, in which one path contains either a simple quantum dot or a decorated quantum dot (with more than one internal state or a parallel path). The possible relevance to some hitherto unexplained experimental features is also discussed.
Phase measurements in open and closed Aharonov-Bohm interferometers
Aharony, A.; Entin-Wohlman, O.; Imry, Y.
2004-01-01
Mesoscopic Aharonov-Bohm interferometers have been used in attempts to measure the transmission phase of a quantum dot which is placed on one arm of the interferometer. Here we review theoretical results for the conductance through such interferometers, for both the closed (two-terminal) and open (multi-terminal) cases. In addition to earlier results for the Coulomb blockade regime, we present new results for the strongly correlated Kondo regime, and test the consistency of the two-slit analy...
Local de Broglie-Bohm Trajectories from Entangled Wavefunctions
Clover, Michael
2007-01-01
We present a local interpretation of what is usually considered to be a nonlocal de Broglie-Bohm trajectory prescription for an entangled singlet state of massive particles. After reviewing various meanings of the term ``nonlocal'', we show that by using appropriately retarded wavefunctions (i.e., the locality loophole) this local model can violate Bell's inequality, without making any appeal to detector inefficiencies. We analyze a possible experimental configuration appropriate to massive t...
Aharonov-Bohm effect of excitons in nanorings
Hu, Hui; Zhu, Jia-Lin; Li, Dai-Jun; Xiong, Jia-Jiong
2001-05-01
The magnetic field effects on excitons in an InAs nanoring are studied theoretically. By numerically diagonalizing the effective-mass Hamiltonian of the problem that can be separated into terms in center-of-mass and relative coordinates, we calculate the low-lying excitonic energy levels and oscillator strengths as a function of the ring width and the strength of an external magnetic field. It is shown that in the presence of Coulomb correlation, the so-called Aharonov-Bohm effect of excitons exists in a finite (but small) width nanoring. However, when the ring width becomes large, the non-simply-connected geometry of nanorings is destroyed, causing the suppression of the Aharonov-Bohm effect. The analytical results are obtained for a narrow-width nanoring in which the radial motion is the fastest one and adiabatically decoupled from the azimuthal motions. The conditional probability distribution calculated for the low-lying excitonic states allows identification of the presence of the Aharonov-Bohm effect. The linear optical susceptibility is also calculated as a function of the magnetic field, to be compared with the future measurements of optical emission experiments on InAs nanorings.
Coherent coupling of two quantum dots embedded in an Aharonov-Bohm ring
Holleitner, A. W.; Decker, C. R.; Eberl, K.; Blick, R. H.
2000-01-01
We define two laterally gated small quantum dots (~ 15 electrons) in an Aharonov-Bohm geometry in which the coupling between the two dots can be broadly changed. For weakly coupled quantum dots we find Aharonov-Bohm oscillations. In an intermediate coupling regime we concentrate on the molecular states of the double dot and extract the magnetic field dependence of the coherent coupling.
On the Aharonov-Bohm Effect and Why Heisenberg Captures Nonlocality Better Than Schr\\"odinger
Aharonov, Yakir
2013-01-01
I discuss in detail the history of the Aharonov-Bohm effect in Bristol and my encounters with Akira Tonomura later on. I then propose an idea that developed following the publication of the Aharonov-Bohm effect, namely the importance of modulo momentum and Heisenberg representation in dealing with non-local quantum phenomena.
Strong unique continuation property of two-dimensional Dirac equations with Aharonov-Bohm fields
Ikoma, Makoto; Yamada, Osanobu
2003-01-01
We study the unique continuation property of two-dimensional Dirac equations with Aharonov-Bohm fields. Some results for the unperturbed Dirac operator are given by De Carli-\\={O}kaji [2]. We are interested in the problem how the singularity of Aharonov-Bohm fields at the origin influences the unique continuation property.
A unified approach to Aharonov-Bohm, Aharonov-Casher and which-path experiments
International Nuclear Information System (INIS)
A unified approach to Aharonov-Bohm, Aharonov-Casher and which-path experiments is presented, using an enlarged Hilbert space. This Hilbert space contains quasi-periodic Aharonov-Bohm wavefunctions R(x+2π)=R(x)exp(iθ) with various values of θ. Thus it can describe which-path Aharonov-Bohm experiments where the phase θ is uncertain due to decoherence that occurs as a result of the observation of the paths of the electric charges. The same Hilbert space contains quasi-periodic Aharonov-Casher wavefunctions which describe magnetic flux tubes winding around an electric charge and which are related through a Fourier transform to the Aharonov-Bohm wavefunctions. The duality between these two phenomena is discussed. The decoherence occurring in which-path experiments is studied quantitatively. Magnetic and electric superselection rules, appropriate for the Aharonov-Bohm and Aharonov-Casher experiments correspondingly, are also discussed. (author)
International Nuclear Information System (INIS)
Starting from the non-relativistic field theory of spin- fermions interacting through the Abelian Chern-Simons term, we show that the quantized field theory leads, in the two-particle sector, to a two-particle Aharonov-Bohm-like Schroedinger equation with an antisymmetric (fermionic) wavefunction and without a delta function term. Calculating perturbatively the field-theoretic two-particle scattering amplitude up to one-loop order, we show that, in contrast to the scalar theory, the contribution of all the one-loop diagrams is finite and null, and that of the tree level ones coincides with the exact amplitude. Further, the Pauli matter-magnetic field interaction term is shown not to contribute to the amplitude to this order. (author)
On the Locality Principle Keeping in Aharonov-Bohm Effect
Gritsunov, Alexander
2013-01-01
The locality principle fulfillment in the Aharonov-Bohm (AB) effect is analyzed from the point of view of a self-sufficient potential formalism based on so-called gradient hypothesis in electrodynamics. The "magnetic" kind of AB effect is examined (as the quantum charged particle moves to an infinitely long solenoid with a permanent current), and no locality principle violation recognized if the gradient hypothesis is used. A conclusion is made that AB effect is no longer a physical and electrodynamic "paradox".
Aharonov-Bohm detection of two-dimensional magnetostatic cloaks
Valagiannopoulos, Constantinos A.; Askarpour, Amir Nader; Alù, Andrea
2015-12-01
Two-dimensional magnetostatic cloaks, even when perfectly designed to mitigate the magnetic field disturbance of a scatterer, may be still detectable with Aharonov-Bohm (AB) measurements, and therefore may affect quantum interactions and experiments with elongated objects. We explore a multilayered cylindrical cloak whose permeability profile is tailored to nullify the magnetic-flux perturbation of the system, neutralizing its effect on AB measurements, and simultaneously optimally suppress the overall scattering. In this way, our improved magnetostatic cloak combines substantial mitigation of the magnetostatic scattering response with zero detectability by AB experiments.
Hidden Photons in Aharonov-Bohm-Type Experiments
Arias, Paola; Diaz, Marco Aurelio; Jaeckel, Joerg; Koch, Benjamin; Redondo, Javier
2016-01-01
We discuss the Aharonov-Bohm effect in the presence of hidden photons kinetically mixed with the ordinary electromagnetic photons. The hidden photon field causes a slight phase shift in the observable interference pattern. It is then shown how the limited sensitivity of this experiment can be largely improved. The key observation is that the hidden photon field causes a leakage of the ordinary magnetic field into the supposedly field-free region. The direct measurement of this magnetic field can provide a sensitive experiment with a good discovery potential, particularly below the $\\sim$ meV mass range for hidden photons.
Spectroscopic detectability of the molecular Aharonov-Bohm effect
Englman, R.
2016-01-01
It is theoretically shown that the emission spectra from an excited Jahn-Teller state in which the ions undergo a forced periodic trajectory have an M-shaped form, directly due to the sign change by the Berry-phase factor. The presence of a weak spectral sideline is noted and the effects of a nonlinear vibronic coupling are calculated. Experimental verifications of the results, e.g., on R'-centers in LiF, are proposed. The dip in the M-shaped emission line is a novel, and perhaps unique, spectroscopic manifestation of the "molecular Aharonov-Bohm effect."
Expectation values in the Aharonov-Bohm effect
International Nuclear Information System (INIS)
It has been well established that, as predicted by Aharonov and Bohm, electron interference patterns can be shifted by the introduction of electromagnetic potentials, even if the electrons never enter the region in which the fields are nonzero. In this paper it is proved that, even though the interference pattern shifts, none of the moments of the electron's position r, nor of its kinetic momentum π, are affected. On the other hand, it is proved that the expectation value of the operator sin aπ (with a a certain fixed vector), which was first introduced by Aharonov, Pendleton and Peterson, does shift
Inelastic transport through Aharonov-Bohm interferometer in Kondo regime
Energy Technology Data Exchange (ETDEWEB)
Yoshii, Ryosuke; Eto, Mikio [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Sakano, Rui [Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581 (Japan); Affleck, Ian [Department of Physics and Astronomy, University of British Columbia, Vancouver (Canada)
2013-12-04
We formulate elastic and inelastic parts of linear conductance through an Aharonov-Bohm (AB) ring with an embedded quantum dot in the Kondo regime. The inelastic part G{sub inel} is proportional to T{sup 2} when the temperature T is much smaller than the Kondo temperature T{sub K}, whereas it is negligibly small compared with elastic part G{sub el} when T ≫ T{sub K}. G{sub inel} weakly depends on the magnetic flux penetrating the AB ring, which disturbs the precise detection of G{sub el}/(G{sub el}+G{sub inel}) by the visibility of AB oscillation.
Dispersionless forces and the Aharonov-Bohm effect
Batelaan, H.; Becker, M.
2015-11-01
The independence of the Aharonov-Bohm phase shift on particle velocity is one of its defining properties. The classical counterpart to this dispersionless behavior is the absence of forces along the direction of motion of the particle. A reevaluation of the experimental demonstration that forces are absent in the AB physical system is given, including previously unpublished data. It is shown that the debate on the presence or absence of forces is not settled. Experiments that measure the influence of magnetic permeability on forces and search for dispersionless quantum forces are proposed.
Patterns of the Aharonov-Bohm oscillations in graphene nanorings
Romanovsky, Igor; Yannouleas, Constantine; Landman, Uzi
2012-01-01
Using extensive tight-binding calculations, we investigate (including the spin) the Aharonov-Bohm (AB) effect in monolayer and bilayer trigonal and hexagonal graphene rings with zigzag boundary conditions. Unlike the previous literature, we demonstrate the universality of integer (hc/e) and half-integer (hc/2e) values for the period of the AB oscillations as a function of the magnetic flux, in consonance with the case of mesoscopic metal rings. Odd-even (in the number of Dirac electrons, N) s...
Aharonov endash Bohm scattering: The role of the incident wave
International Nuclear Information System (INIS)
The scattering problem under the influence of the Aharonov endash Bohm (AB) potential is reconsidered. By solving the Lippmann endash Schwinger (LS) equation we obtain the wave function of the scattering state in this system. In spite of working with a plane wave as an incident wave we obtain the same wave function as was given by Aharonov and Bohm. Another method to solve the scattering problem is given by making use of a modified version of Gordon close-quote s idea, which was invented to consider the scattering by the Coulomb potential. These two methods give the same result, which guarantees the validity of taking an incident plane wave as usual to make an analysis of this scattering problem. The scattering problem by a solenoid of finite radius is also discussed, and we find that the vector potential of the solenoid affects the charged particles, even when the magnitude of the flux is an odd integer as well as a noninteger. It is shown that the unitarity of the S matrix holds provided that a plane wave is taken to be an incident one. copyright 1997 American Institute of Physics
Bohm and Einstein-Sasaki Metrics, Black Holes and Cosmological Event Horizons
Gibbons, G W; Pope, C N
2003-01-01
We study physical applications of the Bohm metrics, which are infinite sequences of inhomogeneous Einstein metrics on spheres and products of spheres of dimension 5 <= d <= 9. We prove that all the Bohm metrics on S^3 x S^2 and S^3 x S^3 have negative eigenvalue modes of the Lichnerowicz operator and by numerical methods we establish that Bohm metrics on S^5 have negative eigenvalues too. We argue that all the Bohm metrics will have negative modes. These results imply that higher-dimensional black-hole spacetimes where the Bohm metric replaces the usual round sphere metric are classically unstable. We also show that the stability criterion for Freund-Rubin solutions is the same as for black-hole stability, and hence such solutions using Bohm metrics will also be unstable. We consider possible endpoints of the instabilities, and show that all Einstein-Sasaki manifolds give stable solutions. We show how Wick rotation of Bohm metrics gives spacetimes that provide counterexamples to a strict form of the Cos...
Bohm and Einstein-Sasaki metrics, black holes, and cosmological event horizons
International Nuclear Information System (INIS)
We study physical applications of the Bohm metrics, which are infinite sequences of inhomogeneous Einstein metrics on spheres and products of spheres of dimension 5≤d≤9. We prove that all the Bohm metrics on S3xS2 and S3xS3 have negative eigenvalue modes of the Lichnerowicz operator acting on transverse traceless symmetric tensors, and by numerical methods we establish that Bohm metrics on S5 have negative eigenvalues too. General arguments suggest that all the Bohm metrics will have negative Lichnerowicz modes. These results imply that generalized higher-dimensional black-hole spacetimes, in which the Bohm metric replaces the usual round sphere metric, are classically unstable. We also show that the classical stability criterion for Freund-Rubin solutions, which are products of Einstein metrics with anti-de Sitter spacetimes, is the same in all dimensions as that for black-hole stability, and hence such solutions based on the Bohm metrics will also be unstable. We consider possible end points of the instabilities, and in particular we show that all Einstein-Sasaki manifolds give stable solutions. Next, we show how analytic continuation of Bohm metrics gives Lorentzian metrics that provide counterexamples to a strict form of the cosmic baldness conjecture, but they are nevertheless consistent with the intuition behind the cosmic no-hair conjectures. We indicate how these Lorentzian metrics may be created 'from nothing' in a no-boundary setting. We argue that Lorentzian Bohm metrics are unstable to decay to de Sitter spacetime. Finally, we argue that noncompact versions of the Bohm metrics have infinitely many negative Lichnerowicz modes, and we conjecture a general relationship between Lichnerowicz eigenvalues and nonuniqueness of the Dirichlet problem for Einstein's equations
Bound states of massive fermions in the Aharonov--Bohm-like fields
Khalilov, V. R.
2014-01-01
Bound states of massive fermions in the Aharonov-Bohm like fields have analytically been studied. The Hamiltonians with the Aharonov--Bohm like potentials are essentially singular and therefore require specification of a one-parameter self-adjoint extension. We construct self-adjoint Dirac Hamiltonians with the Aharonov-Bohm (AB) potential in 2+1 dimensions that are specified by boundary conditions at the origin. It is of interest that for some range of extension parameter the AB potential ca...
Paradoxes of the Aharonov-Bohm and the Aharonov-Casher effects
Vaidman, Lev
2013-01-01
For a believer in locality of Nature, the Aharonov-Bohm effect and the Aharonov-Casher effect are paradoxes. I discuss these and other Aharonov's paradoxes and propose a local explanation of these effects. If the solenoid in the Aharonov-Bohm effect is treated quantum mechanically, the effect can be explained via local interaction between the field of the electron and the solenoid. I argue that the core of the Aharonov-Bohm and the Aharonov-Casher effects is that of quantum entanglement: the ...
Electron in the Aharonov-Bohm potential and Coulomb field in (2+1)-dimensions
International Nuclear Information System (INIS)
One derived the precise solutions of the Dirac equation in 2+1 dimensions and determined the electron energy spectrum in the superposition of the Aharonov-Bohm potential and of the Coulomb potential. The expression for the scattering amplitude is presented as a sum of the amplitudes of scattering in the Aharonov-Bohm potential and in the Coulomb potential. The wave function calibration invariant phase or the energy of the electron bound state are shown to be the observed values. One derived a formula for the cross section of the spin-polarized electron scattering in the Aharonov-Bohm potential
Kirchhoff diffraction optics and the nascent Aharonov-Bohm effect: a theorem
International Nuclear Information System (INIS)
Textbook diffraction optics, Kirchhoff diffraction, is connected to the Aharonov-Bohm effect of quantum mechanics by an easy theorem proved here. The connection is between the Kirchhoff wave field and the Aharonov-Bohm quantum wave field in the limit of zero flux: the 'nascent' Aharonov-Bohm effect. The diffracting opaque screen of Kirchhoff optics is replaced in the quantum mechanics by a magnetic flux line, or loop, in the shape of the boundary edge of the screen. The gauge must be chosen appropriately: a delta function on that surface, spanning the boundary edge, which matches the screen.
Propagator for spinless and spin-1/2 Aharonov-Bohm-Coulomb systems
Park, D. K.; Yoo, Sahng-Kyoon
1997-01-01
The propagator of the spinless Aharonov-Bohm-Coulomb system is derived by following the Duru-Kleinert method. We use this propagator to explore the spin-1/2 Aharonov-Bohm-Coulomb system which contains a point interaction as a Zeeman term. Incorporation of the self-adjoint extension method into the Green's function formalism properly allows us to derive the finite propagator of the spin-1/2 Aharonov-Bohm-Coulomb system. As a by-product, the relation between the self-adjoint extension parameter...
Time-dependent Aharonov–Bohm effect on the noncommutative space
Kai Ma; Jian-Hua Wang; Huan-Xiong Yang
2016-01-01
We study the time-dependent Aharonov–Bohm effect on the noncommutative space. Because there is no net Aharonov–Bohm phase shift in the time-dependent case on the commutative space, therefore, a tiny deviation from zero indicates new physics. Based on the Seiberg–Witten map we obtain the gauge invariant and Lorentz covariant Aharonov–Bohm phase shift in general case on noncommutative space. We find there are two kinds of contribution: momentum-dependent and momentum-independent corrections. Fo...
Aharonov–Bohm effect in resonances for scattering by three solenoids
Tamura, Hideo
2015-01-01
We study how the Aharonov–Bohm effect is reflected in the location of quantum resonances for scattering by three solenoids at large separation. We also discuss what happens in the case of four solenoids.
Revisiting the Marton, Simpson, and Suddeth experimental confirmation of the Aharonov–Bohm effect
Energy Technology Data Exchange (ETDEWEB)
Macdougall, James, E-mail: jbm34@mail.fresnostate.edu [Physics Department, CSU Fresno, Fresno, CA 93740 (United States); Singleton, Douglas, E-mail: dougs@csufresno.edu [Physics Department, CSU Fresno, Fresno, CA 93740 (United States); Vagenas, Elias C., E-mail: elias.vagenas@ku.edu.kw [Theoretical Physics Group, Department of Physics, Kuwait University, P.O. Box 5969, Safat 13060 (Kuwait)
2015-09-04
We perform an “archeological” study of one of the original experiments used as evidence for the static, time-independent Aharonov–Bohm effect. Since the experiment in question involved a time varying magnetic field we show that there are problems with the explanation of this experiment as a confirmation of the static Aharonov–Bohm effect – specifically the previous analysis ignored the electric field which arises in conjunction with a time-varying magnetic flux. We further argue that the results of this experiment do in fact conform exactly to the recent prediction [2,3] of a cancellation between the magnetic and electric phase shifts for the time-dependent Aharonov–Bohm effect. To resolve this issue a new time-dependent Aharonov–Bohm experiment is called for.
The bound state Aharonov-Bohm effect around a cosmic string revisited
Filgueiras, C.; Moraes, Fernando
2005-01-01
In this article we observe that the self-adjoint extension of the Hamiltonian of a particle moving around a shielded cosmic string gives rise to a gravitational analogue of the bound state Aharonov-Bohm effect.
Gauge equivalence classes of flat connections in the Aharonov-Bohm effect
M.A. Aguilar; Isidro, J. M.; Socolovsky, M.
2003-01-01
In this note we present a simplified derivation of the fact that the moduli space of flat connections in the abelian Aharonov-Bohm effect is isomorphic to the circle. The length of this circle is the electric charge.
Revisiting the Marton, Simpson, and Suddeth experimental confirmation of the Aharonov-Bohm effect
Macdougall, James; Singleton, Douglas; Vagenas, Elias C.
2015-09-01
We perform an "archeological" study of one of the original experiments used as evidence for the static, time-independent Aharonov-Bohm effect. Since the experiment in question [1] involved a time varying magnetic field we show that there are problems with the explanation of this experiment as a confirmation of the static Aharonov-Bohm effect - specifically the previous analysis ignored the electric field which arises in conjunction with a time-varying magnetic flux. We further argue that the results of this experiment do in fact conform exactly to the recent prediction [2,3] of a cancellation between the magnetic and electric phase shifts for the time-dependent Aharonov-Bohm effect. To resolve this issue a new time-dependent Aharonov-Bohm experiment is called for.
Uniform asymptotic formula for the Aharonov Bohm wavefield
Hannay, J. H.
2016-06-01
A uniform asymptotic formula for the Aharonov–Bohm wavefield (that of a plane quantum wave scattered by a thin straight solenoid) far away from the solenoid is obtained in a direct way. Actually quite good accuracy is achieved even down to one wavelength away. The error is numerically of order radius^(‑3/2) for all values of polar angle, including directly forwards. Several previous formulas, uniform and otherwise, for the far field limit exist in the literature. All contain the essential ingredient: the Fresnel integral (complex error function), but ordinarily the error in these formulas is of order radius^(‑1/2) in the forwards direction where the Fresnel contribution is most important.
An Aharonov-Bohm interferometer for determining Bloch band topology.
Duca, L; Li, T; Reitter, M; Bloch, I; Schleier-Smith, M; Schneider, U
2015-01-16
The geometric structure of a single-particle energy band in a solid is fundamental for a wide range of many-body phenomena and is uniquely characterized by the distribution of Berry curvature over the Brillouin zone. We realize an atomic interferometer to measure Berry flux in momentum space, in analogy to an Aharonov-Bohm interferometer that measures magnetic flux in real space. We demonstrate the interferometer for a graphene-type hexagonal optical lattice loaded with bosonic atoms. By detecting the singular π Berry flux localized at each Dirac point, we establish the high momentum resolution of this interferometric technique. Our work forms the basis for a general framework to fully characterize topological band structures. PMID:25525160
Geometric phase of a classical Aharonov–Bohm Hamiltonian
International Nuclear Information System (INIS)
We present a gauge-invariant approach for associating a geometric phase with the phase space trajectory of a classical dynamical system. As an application, we consider the classical analog of the quantum Aharonov–Bohm (AB) Hamiltonian for a charged particle orbiting around a current carrying long thin solenoid. We compute the classical geometric phase of a closed phase space trajectory, and also determine its dependence on the magnetic flux enclosed by the orbit. We study the similarities and differences between this classical geometric phase and the AB phase acquired by the wave function of the quantum AB Hamiltonian. We suggest an experiment to measure the geometric phase for the classical AB system, by using an appropriate optical fiber ring interferometer.
Scattering on two Aharonov-Bohm vortices with opposite fluxes
International Nuclear Information System (INIS)
The scattering of an incident plane wave on two Aharonov-Bohm vortices with opposite fluxes is considered in detail. The presence of the vortices imposes non-trivial boundary conditions for the partial waves on a cut joining the two vortices. These conditions result in an infinite system of equations for scattering amplitudes between incoming and outgoing partial waves, which can be solved numerically. The main focus of the paper is the analytic determination of the scattering amplitude in two limits, the small flux limit and the limit of small vortex separation. In the latter limit the dominant contribution comes from the S-wave amplitude. Calculating it, however, still requires solving an infinite system of equations, which is achieved by the Riemann-Hilbert method. The results agree well with the numerical calculations.
Geometric phase of a classical Aharonov–Bohm Hamiltonian
Energy Technology Data Exchange (ETDEWEB)
Balakrishnan, Radha, E-mail: radha@imsc.res.in [The Institute of Mathematical Sciences, Chennai 600 113 (India); Satija, Indubala I. [Department of Physics, George Mason University, Fairfax, VA 22030 (United States)
2013-06-17
We present a gauge-invariant approach for associating a geometric phase with the phase space trajectory of a classical dynamical system. As an application, we consider the classical analog of the quantum Aharonov–Bohm (AB) Hamiltonian for a charged particle orbiting around a current carrying long thin solenoid. We compute the classical geometric phase of a closed phase space trajectory, and also determine its dependence on the magnetic flux enclosed by the orbit. We study the similarities and differences between this classical geometric phase and the AB phase acquired by the wave function of the quantum AB Hamiltonian. We suggest an experiment to measure the geometric phase for the classical AB system, by using an appropriate optical fiber ring interferometer.
Thermoelectric effects in a rectangular Aharonov-Bohm geometry
Pye, A. J.; Faux, D. A.; Kearney, M. J.
2016-04-01
The thermoelectric transport properties of a rectangular Aharonov-Bohm ring at low temperature are investigated using a theoretical approach based on Green's functions. The oscillations in the transmission coefficient as the field is varied can be used to tune the thermoelectric response of the ring. Large magnitude thermopowers are obtainable which, in conjunction with low conductance, can result in a high thermoelectric figure of merit. The effects of single site impurities and more general Anderson disorder are considered explicitly in the context of evaluating their effect on the Fano-type resonances in the transmission coefficient. Importantly, it is shown that even for moderate levels of disorder, the thermoelectric figure of merit can remain significant, increasing the appeal of such structures from the perspective of specialist thermoelectric applications.
Magnetic edge states in Aharonov-Bohm graphene quantum rings
Energy Technology Data Exchange (ETDEWEB)
Farghadan, R., E-mail: rfarghadan@kashanu.ac.ir; Heidari Semiromi, E. [Department of Physics, University of Kashan, Kashan (Iran, Islamic Republic of); Saffarzadeh, A. [Department of Physics, Payame Noor University, P.O. Box 19395-3697 Tehran (Iran, Islamic Republic of); Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada)
2013-12-07
The effect of electron-electron interaction on the electronic structure of Aharonov-Bohm (AB) graphene quantum rings (GQRs) is explored theoretically using the single-band tight-binding Hamiltonian and the mean-field Hubbard model. The electronic states and magnetic properties of hexagonal, triangular, and circular GQRs with different sizes and zigzag edge terminations are studied. The results show that, although the AB oscillations in the all types of nanoring are affected by the interaction, the spin splitting in the AB oscillations strongly depends on the geometry and the size of graphene nanorings. We found that the total spin of hexagonal and circular rings is zero and therefore, no spin splitting can be observed in the AB oscillations. However, the non-zero magnetization of the triangular rings breaks the degeneracy between spin-up and spin-down electrons, which produces spin-polarized AB oscillations.
Patterns of the Aharonov-Bohm oscillations in graphene nanorings
Romanovsky, Igor; Yannouleas, Constantine; Landman, Uzi
2012-04-01
Using extensive tight-binding calculations, we investigate (including the spin) the Aharonov-Bohm (AB) effect in monolayer and bilayer trigonal and hexagonal graphene rings with zigzag boundary conditions. Unlike the previous literature, we demonstrate the universality of integer (hc/e) and half-integer (hc/2e) values for the period of the AB oscillations as a function of the magnetic flux, in consonance with the case of mesoscopic metal rings. Odd-even (in the number of Dirac electrons, N) sawtooth-type patterns relating to the halving of the period have also been found; they are more numerous for a monolayer hexagonal ring, compared to the cases of a trigonal and a bilayer hexagonal ring. Additional, more complicated patterns are also present, depending on the shape of the graphene ring. Overall, the AB patterns repeat themselves as a function of N, with periods proportional to the number of the sides of the rings.
Magnetic edge states in Aharonov-Bohm graphene quantum rings
Farghadan, R.; Saffarzadeh, A.; Heidari Semiromi, E.
2013-12-01
The effect of electron-electron interaction on the electronic structure of Aharonov-Bohm (AB) graphene quantum rings (GQRs) is explored theoretically using the single-band tight-binding Hamiltonian and the mean-field Hubbard model. The electronic states and magnetic properties of hexagonal, triangular, and circular GQRs with different sizes and zigzag edge terminations are studied. The results show that, although the AB oscillations in the all types of nanoring are affected by the interaction, the spin splitting in the AB oscillations strongly depends on the geometry and the size of graphene nanorings. We found that the total spin of hexagonal and circular rings is zero and therefore, no spin splitting can be observed in the AB oscillations. However, the non-zero magnetization of the triangular rings breaks the degeneracy between spin-up and spin-down electrons, which produces spin-polarized AB oscillations.
Magnetic edge states in Aharonov-Bohm graphene quantum rings
International Nuclear Information System (INIS)
The effect of electron-electron interaction on the electronic structure of Aharonov-Bohm (AB) graphene quantum rings (GQRs) is explored theoretically using the single-band tight-binding Hamiltonian and the mean-field Hubbard model. The electronic states and magnetic properties of hexagonal, triangular, and circular GQRs with different sizes and zigzag edge terminations are studied. The results show that, although the AB oscillations in the all types of nanoring are affected by the interaction, the spin splitting in the AB oscillations strongly depends on the geometry and the size of graphene nanorings. We found that the total spin of hexagonal and circular rings is zero and therefore, no spin splitting can be observed in the AB oscillations. However, the non-zero magnetization of the triangular rings breaks the degeneracy between spin-up and spin-down electrons, which produces spin-polarized AB oscillations
Noncommutative analogue Aharonov-Bohm effect and superresonance
Anacleto, M A; Passos, E
2012-01-01
We consider the idea of modeling a rotating acoustic black hole by an idealized draining bathtub vortex which is a planar circulating flow phenomenon with a sink at the origin. We find the acoustic metric for this phenomenon from a noncommutative Abelian Higgs model. As such the acoustic metric not only describes a rotating acoustic black hole but also inherits the noncommutative characteristic of the spacetime. We address the issues of superresonance and analogue Aharonov-Bohm (AB) effect in this background. We mainly show that the scattering of planar waves by a draining bathtub vortex leads to a modified AB effect and due to spacetime noncommutativity, the phase shift persists even in the limit where the parameters associated with the circulation and draining vanish. Finally, we also find that the analogue AB effect and superresonance are competing phenomena at a noncommutative spacetime.
Noncommutative analogue Aharonov-Bohm effect and superresonance
Anacleto, M. A.; Brito, F. A.; Passos, E.
2013-06-01
We consider the idea of modeling a rotating acoustic black hole by an idealized draining bathtub vortex which is a planar circulating flow phenomenon with a sink at the origin. We find the acoustic metric for this phenomenon from a noncommutative Abelian Higgs model. As such the acoustic metric not only describes a rotating acoustic black hole but also inherits the noncommutative characteristic of the spacetime. We address the issues of superresonance and analogue Aharonov-Bohm (AB) effect in this background. We mainly show that the scattering of planar waves by a draining bathtub vortex leads to a modified AB effect and due to spacetime noncommutativity, the phase shift persists even in the limit where the parameters associated with the circulation and draining vanish. Finally, we also find that the analogue AB effect and superresonance are competing phenomena at a noncommutative spacetime.
Bohm-Aharonov type effects in dissipative atomic systems
Solomon, A I; Solomon, Allan I.; Schirmer, Sonia G.
2005-01-01
A state in quantum mechanics is defined as a positive operator of norm 1. For finite systems, this may be thought of as a positive matrix of trace 1. This constraint of positivity imposes severe restrictions on the allowed evolution of such a state. From the mathematical viewpoint, we describe the two forms of standard dynamical equations - global (Kraus) and local (Lindblad) - and show how each of these gives rise to a semi-group description of the evolution. We then look at specific examples from atomic systems, involving 3-level systems for simplicity, and show how these mathematical constraints give rise to non-intuitive physical phenomena, reminiscent of Bohm-Aharonov effects. In particular, we show that for a multi-level atomic system it is generally impossible to isolate the levels, and this leads to observable effects on the population relaxation and decoherence.
Description of the Magnetic Field and Divergence of Multisolenoid Aharonov-Bohm Potential
Directory of Open Access Journals (Sweden)
Araz R. Aliev
2016-01-01
Full Text Available Explicit formulas for the magnetic field and divergence of multisolenoid Aharonov-Bohm potential are obtained; the mathematical essence of this potential is explained. It is shown that the magnetic field and divergence of this potential are very singular generalized functions concentrated at a finite number of thin solenoids. Deficiency index is found for the minimal operator generated by the Aharonov-Bohm differential expression.
Magnetic Catalysis of Dynamical Symmetry Breaking and Aharonov-Bohm Effect
Miransky, V.A.
1998-01-01
The phenomenon of the magnetic catalysis of dynamical symmetry breaking is based on the dimensional reduction $D\\to D-2$ in the dynamics of fermion pairing in a magnetic field. We discuss similarities between this phenomenon and the Aharonov-Bohm effect. This leads to the interpretation of the dynamics of the (1+1)-dimensional Gross-Neveu model with a non-integer number of fermion colors as a quantum field theoretical analogue of the Aharonov-Bohm dynamics.
Radiation of Supersymmetric Particles from Aharonov-Bohm R-string
Ookouchi, Yutaka; Yonemoto, Takahiro
2014-01-01
We study radiation of supersymmetric particles from an Aharonov-Bohm string associated with a discrete R-symmetry. Radiation of the lightest supersymmetric particle, when combined with the observed dark matter density, imposes constraints on the string tension or the freeze-out temperature of the particle. We also calculate the amplitude for Aharonov-Bohm radiation of massive spin $3/2$ particles.
The Aharonov-Casher and scalar Aharonov-Bohm topological effects
Dulat, Sayipjamal; Ma, Kai
2012-01-01
We reexamine the topological and nonlocal natures of the Aharonov-Casher and scalar Aharonov-Bohm phase effects. The underlying U(1) gauge structure is exhibited explicitly. And the conditions for developing topological Aharonov-Casher and scalar Aharonov-Bohm phases are clarified. We analyse the arguments of M. Peshkin and H. J. Lipkin (Phys. Rev. Lett. 74, 2847(1995)) in detail and show that they are based on the wrong Hamiltonian which yields their conclusion incorrect.
Whirling Waves and the Aharonov-Bohm Effect for Relativistic Spinning Particles
Girotti, H. O.; Romero, F. Fonseca
1996-01-01
The formulation of Berry for the Aharonov-Bohm effect is generalized to the relativistic regime. Then, the problem of finding the self-adjoint extensions of the (2+1)-dimensional Dirac Hamiltonian, in an Aharonov-Bohm background potential, is solved in a novel way. The same treatment also solves the problem of finding the self-adjoint extensions of the Dirac Hamiltonian in a background Aharonov-Casher.
Gravito-electromagnetic Aharonov-Bohm effect: some rotation effects revised
Ruggiero, Matteo Luca
2010-01-01
By means of the description of the standard relative dynamics in terms of gravito-electromagnetic fields, in the context of natural splitting, we formally introduce the gravito-magnetic Aharonov-Bohm effect. Then, we interpret the Sagnac effect as a gravito-magnetic Aharonov-Bohm effect and we exploit this formalism for studying the General Relativistic corrections to the Sagnac effect in stationary and axially symmetric geometries.
Bagrov, V. G.; Gitman, D. M.; Tlyachev, V. B.
2002-01-01
We present new exact solutions (in 3+1 and 2+1 dimensions) of relativistic wave equations (Klein-Gordon and Dirac) in external electromagnetic fields of special form. These fields are combinations of Aharonov-Bohm solenoid field and some additional electric and magnetic fields. In particular, as such additional fields, we consider longitudinal electric and magnetic fields, some crossed fields, and some special non-uniform fields. The solutions obtained can be useful to study Aharonov-Bohm eff...
Longhi, Stefano
2014-01-01
We suggest a method for trapping photons in quasi one-dimensional waveguide or coupled-resonator lattices, which is based on an optical analogue of the Aharonov-Bohm cages for charged particles. Light trapping results from a destructive interference of Aharonov-Bohm type induced by a synthetic magnetic field, which is realized by periodic modulation of the waveguide/resonator propagation constants/resonances.
Description of the Magnetic Field and Divergence of Multisolenoid Aharonov-Bohm Potential
Araz R. Aliev; Eyvazov, Elshad H.; Said F. M. Ibrahim; Hassan A. Zedan
2016-01-01
Explicit formulas for the magnetic field and divergence of multisolenoid Aharonov-Bohm potential are obtained; the mathematical essence of this potential is explained. It is shown that the magnetic field and divergence of this potential are very singular generalized functions concentrated at a finite number of thin solenoids. Deficiency index is found for the minimal operator generated by the Aharonov-Bohm differential expression.
Path integrals with topological constraints: Aharonov-Bohm effect and polymer entanglements
Wiegel, F.W.
1981-01-01
For Wiener- and Feynman integrals over paths with certain topological properties we compare various methods for explicit calculation. This leads to a one-to-one correspondence between the Aharonov-Bohm effect and a certain polymer entanglement problem. We briefly comment on two generalizations of the Aharonov-Bohm effect. First, we consider this effect due to a closed magnetic flux loop of arbitrary shape; next, we consider the combined effect due to a gas of microscopic magnetic flux loops.
Photon mass and quantum effects of the Aharonov-Bohm type
Spavieri, G.; M. Rodriguez
2007-01-01
The magnetic field due to the photon rest mass $m_{ph}$ modifies the standard results of the Aharonov-Bohm effect for electrons, and of other recent quantum effects. For the effect involving a coherent superposition of beams of particles with opposite electromagnetic properties, by means of a table-top experiment, the limit $m_{ph}x10^{-51}g$ is achievable, improving by 6 orders of magnitude that derived by Boulware and Deser for the Aharonov-Bohm effect.
The Aharonov-Bohm and Aharonov-Casher effects and electromagnetic angular momentum
International Nuclear Information System (INIS)
A semiclassical explanation for the Aharonov-Bohm and Aharonov-Casher effects is presented. It is shown that these quantum-mechanical effects derive from nontrivial electromagnetic angular momentum inherent to a system containing both charges and magnetic dipoles. It is emphasized that a unified description of the Aharonov-Bohm effect with a solenoid of general shape, both open and closed, is developed in terms of the electromagnetic angular momentum carried by the flux lines that constitute real magnetic flux. (orig.)
Two-particle Aharonov-Bohm effect and Entanglement in the electronic Hanbury Brown Twiss setup
Samuelsson, Martin Peter; Sukhorukov, Eugene; Buttiker, Markus
2003-01-01
We analyze a Hanbury Brown-Twiss geometry in which particles are injected from two independent sources into a mesoscopic conductor in the quantum Hall regime. All partial waves end in different reservoirs without generating any single-particle interference; in particular, there is no single-particle Aharonov-Bohm effect. However, exchange effects lead to two-particle Aharonov-Bohm oscillations in the zero-frequency current cross correlations. We demonstrate that this is related to two-particl...
Aharonov-Bohm effect in an electron-hole graphene ring system
D. Smirnov; Schmidt, H; Haug, R. J.
2012-01-01
Aharonov-Bohm oscillations are observed in a graphene quantum ring with a top gate covering one arm of the ring. As graphene is a gapless semiconductor this geometry allows to study not only the quantum interference of electrons with electrons or holes with holes but also the unique situation of quantum interference between electrons and holes. The period and amplitude of the observed Aharonov-Bohm oscillations are independent of the sign of the applied gate voltage showing the equivalence be...
Longhi, Stefano
2014-10-15
We suggest a method for trapping photons in quasi-one-dimensional waveguide or coupled-resonator lattices, which is based on an optical analogue of the Aharonov-Bohm cages for charged particles. Light trapping results from a destructive interference of Aharonov-Bohm type induced by a synthetic magnetic field, which is realized by periodic modulation of the waveguide/resonator propagation constants/resonances. PMID:25361112
What did we learn from the Aharonov-Bohm effect? Is spin 1/2 different?
International Nuclear Information System (INIS)
I review what has been learned about fundamental issues in quantum mechanics from the Aharonov-Bohm effect. Following that, I consider the Aharonov-Casher effect and the Scalar Aharonov-Bohm effect, in both of which a spin-1/2 particle interacts with a local electromagnetic field through its magnetic moment, and conclude that those effects can be described as observable effects of local torques
The Aharonov-Bohm-Casher ring-dot as a flux-tunable resonant tunneling diode
Citro, R; Romeo, F.
2008-01-01
A mesoscopic ring subject to the Rashba spin-orbit interaction and sequentially coupled to an interacting quantum dot, in the presence of Aharonov-Bohm flux, is proposed as a flux tunable tunneling diode. The analysis of the conductance by means of the nonequilibrium Green's function technique, shows an intrinsic bistability at varying the Aharonov-Bohm flux when 2U > \\pi \\Gamma, U being the charging energy on the dot and \\Gamma the effective resonance width. The bistability properties are di...
Statically screened ion potential and Bohm potential in a quantum plasma
International Nuclear Information System (INIS)
The effective potential Φ of a classical ion in a weakly correlated quantum plasma in thermodynamic equilibrium at finite temperature is well described by the random phase approximation screened Coulomb potential. Additionally, collision effects can be included via a relaxation time ansatz (Mermin dielectric function). These potentials are used to study the quality of various statically screened potentials that were recently proposed by Shukla and Eliasson (SE) [Phys. Rev. Lett. 108, 165007 (2012)], Akbari-Moghanjoughi (AM) [Phys. Plasmas 22, 022103 (2015)], and Stanton and Murillo (SM) [Phys. Rev. E 91, 033104 (2015)] starting from quantum hydrodynamic (QHD) theory. Our analysis reveals that the SE potential is qualitatively different from the full potential, whereas the SM potential (at any temperature) and the AM potential (at zero temperature) are significantly more accurate. This confirms the correctness of the recently derived [Michta et al., Contrib. Plasma Phys. 55, 437 (2015)] pre-factor 1/9 in front of the Bohm term of QHD for fermions
NonAbelian Vortices, Large Winding Limits and Aharonov-Bohm Effects
Bolognesi, Stefano; Konishi, Kenichi
2015-01-01
Remarkable simplification arises from considering vortex equations in the large winding limit. This was recently used in [1] to display all sorts of vortex zeromodes, the orientational, translational, fermionic as well as semi-local, and to relate them to the apparently distinct phenomena of the Nielsen-Olesen-Ambjorn magnetic instabilities. Here we extend these analyses to more general types of BPS nonAbelian vortices, taking as a prototype a system with gauged U(1) x SU(N) x SU(N) symmetry where the VEV of charged scalar fields in the bifundamental representation breaks the symmetry to SU(N)_{l+r} . The presence of the massless SU(N)_{l+r} gauge fields in 4D bulk introduces all sorts of non-local, topological phenomena such as the nonAbelian Aharonov-Bohm effects, which in the theory with global SU(N)_r group (g_r=0) are washed away by the strongly fluctuating orientational zeromodes in the worldsheet. Physics changes qualitatively at the moment the right gauge coupling constant g_r is turned on.
The Aharanov-Bohm effect, magnetic monopoles and reversal in spin-ice lattices.
Pollard, Shawn D; Zhu, Yimei
2013-06-01
The proof of the Aharonov-Bohm (AB) effect has been one of the most important experiments of the last century and used as essential evidence for the theory of gauge fields. In this article, we look at its fundamental relation to the Dirac monopole and string. Despite the Dirac string being invisible to the AB effect, it can be used to study emergent quasiparticles in condensed matter settings that behave similar to the fundamental monopoles and strings between them. We utilize phase-imaging method based on the AB effect to study the ordering in a one-model system - that of frustrated spin ice - to understand the ordering processes that occur during a magnetic field reversal cycle. The reversal is linked to the propagation of monopole defects linked by flux channels, reminiscent of Dirac strings. Monopole interactions govern the defect densities within the lattice. Furthermore, we exploit these interactions to propose a new ordering method in which high degrees of ground-state ordering can be achieved in a frustrated system. PMID:23549453
Randazzo, J. M.; Ancarani, L. U.
2015-12-01
For the single differential cross section (SDCS) for hydrogen ionization by electron impact (e -H problem), we propose a correction to the flux formula given by R. Peterkop [Theory of Ionization of Atoms by Electron Impact (Colorado Associated University Press, Boulder, 1977)]. The modification is based on an alternative way of defining the kinetic energy fraction, using Bohm's definition of velocities instead of the usual asymptotic kinematical, or geometrical, approximation. It turns out that the solution-dependent, modified energy fraction is equally related to the components of the probability flux. Compared to what is usually observed, the correction yields a finite and well-behaved SDCS value in the asymmetrical situation where one of the continuum electrons carries all the energy while the other has zero energy. We also discuss, within the S -wave model of the e -H ionization process, the continuity of the SDCS derivative at the equal energy sharing point, a property not so clearly observed in published benchmark results obtained with integral and S -matrix formulas with unequal final states.
Wang, Dehua
2014-09-01
The Aharonov-Bohm (AB) effect in the photodetachment microscopy of the H- ions in an electric field has been studied on the basis of the semiclassical theory. After the H- ion is irradiated by a laser light, they provide a coherent electron source. When the detached electron is accelerated by a uniform electric field, two trajectories of a detached electron which run from the source to the same point on the detector, will interfere with each other and lead to an interference pattern in the photodetachment microscopy. After the solenoid is electrified beside the H- ion, even though no Lorentz force acts on the electron outside the solenoid, the photodetachment microscopy interference pattern on the detector is changed with the variation in the magnetic flux enclosed by the solenoid. This is caused by the AB effect. Under certain conditions, the interference pattern reaches the macroscopic dimensions and could be observed in a direct AB effect experiment. Our study can provide some predictions for the future experimental study of the AB effect in the photodetachment microscopy of negative ions.
Tadić, M.; Arsoski, V.; Čukarić, N.; Peeters, F. M.
2013-12-01
The excitonic Aharonov-Bohm oscillations in type-I nanorings are found to be caused by anticrossings between exciton states. These anticrossings are analyzed by a tight-binding-like model of exciton states. The criteria for the existence of the excitonic Aharonov-Bohm oscillations are formulated. For nanorings of realistic width and height, the range of values of the inner radius where the excitonic Aharonov-Bohm oscillations exist is found.
Time-dependent Aharonov-Bohm effect on the noncommutative space
Ma, Kai; Wang, Jian-Hua; Yang, Huan-Xiong
2016-08-01
We study the time-dependent Aharonov-Bohm effect on the noncommutative space. Because there is no net Aharonov-Bohm phase shift in the time-dependent case on the commutative space, therefore, a tiny deviation from zero indicates new physics. Based on the Seiberg-Witten map we obtain the gauge invariant and Lorentz covariant Aharonov-Bohm phase shift in general case on noncommutative space. We find there are two kinds of contribution: momentum-dependent and momentum-independent corrections. For the momentum-dependent correction, there is a cancellation between the magnetic and electric phase shifts, just like the case on the commutative space. However, there is a non-trivial contribution in the momentum-independent correction. This is true for both the time-independent and time-dependent Aharonov-Bohm effects on the noncommutative space. However, for the time-dependent Aharonov-Bohm effect, there is no overwhelming background which exists in the time-independent Aharonov-Bohm effect on both commutative and noncommutative space. Therefore, the time-dependent Aharonov-Bohm can be sensitive to the spatial noncommutativity. The net correction is proportional to the product of the magnetic fluxes through the fundamental area represented by the noncommutative parameter θ, and through the surface enclosed by the trajectory of charged particle. More interestingly, there is an anti-collinear relation between the logarithms of the magnetic field B and the averaged flux Φ / N (N is the number of fringes shifted). This nontrivial relation can also provide a way to test the spatial noncommutativity. For BΦ / N ∼ 1, our estimation on the experimental sensitivity shows that it can reach the 10 GeV scale. This sensitivity can be enhanced by using stronger magnetic field strength, larger magnetic flux, as well as higher experimental precision on the phase shift.
Time-dependent Aharonov–Bohm effect on the noncommutative space
Directory of Open Access Journals (Sweden)
Kai Ma
2016-08-01
Full Text Available We study the time-dependent Aharonov–Bohm effect on the noncommutative space. Because there is no net Aharonov–Bohm phase shift in the time-dependent case on the commutative space, therefore, a tiny deviation from zero indicates new physics. Based on the Seiberg–Witten map we obtain the gauge invariant and Lorentz covariant Aharonov–Bohm phase shift in general case on noncommutative space. We find there are two kinds of contribution: momentum-dependent and momentum-independent corrections. For the momentum-dependent correction, there is a cancellation between the magnetic and electric phase shifts, just like the case on the commutative space. However, there is a non-trivial contribution in the momentum-independent correction. This is true for both the time-independent and time-dependent Aharonov–Bohm effects on the noncommutative space. However, for the time-dependent Aharonov–Bohm effect, there is no overwhelming background which exists in the time-independent Aharonov–Bohm effect on both commutative and noncommutative space. Therefore, the time-dependent Aharonov–Bohm can be sensitive to the spatial noncommutativity. The net correction is proportional to the product of the magnetic fluxes through the fundamental area represented by the noncommutative parameter θ, and through the surface enclosed by the trajectory of charged particle. More interestingly, there is an anti-collinear relation between the logarithms of the magnetic field B and the averaged flux Φ/N (N is the number of fringes shifted. This nontrivial relation can also provide a way to test the spatial noncommutativity. For BΦ/N∼1, our estimation on the experimental sensitivity shows that it can reach the 10 GeV scale. This sensitivity can be enhanced by using stronger magnetic field strength, larger magnetic flux, as well as higher experimental precision on the phase shift.
From Bohm to Aspect: Philosophy Enters the Optics Laboratory
Freire, Olival
2005-04-01
My talk deals with the shifting boundary between philosophy and science from the 1950s to the 1980s, as it relates to the foundations of quantum mechanics. The poor reception of Bohm's causal interpretation of quantum mechanics was related to the idea that it was merely a philosophical inquiry. The controversy it stirred up, however, produced, as a byproduct, the reanalysis of John von Neumann's proof, and 10 years later, this led John Stewart Bell to his theorem. In telling this story, I examine the professional circumstances, backgrounds, and profiles of three physicists, Abner Shimony, John F. Clauser, and Alain Aspect, who were associated with the path from Bell's theoretical work to the experimental tests of the Bell inequalities. I argue that: (1) What was considered good physics after Aspect's 1982 experiments was once considered by many a philosophical matter instead of a scientific one. (2) The path from philosophy to physics was a slow and sinuous one and involved a change in the physics community's attitude about the status of the foundations of quantum mechanics. (3) Foundations of quantum mechanics entered the optics laboratory, but did not lose its philosophical implications.
Aharonov-Bohm phases in a quantum LC circuit
Cao, ChunJun; Yao, Yuan; Zhitnitsky, Ariel R.
2016-03-01
We study novel types of contributions to the partition function of the Maxwell system defined on a small compact manifold. These contributions, often not addressed in the perturbative treatment with physical photons, emerge as a result of tunneling transitions between topologically distinct but physically identical vacuum winding states. These new terms give an extra contribution to the Casimir pressure, yet to be measured. We argue that this effect is highly sensitive to a small external electric field, which should be contrasted with the conventional Casimir effect, where the vacuum photons are essentially unaffected by any external field. Furthermore, photons will be emitted from the vacuum in response to a time-dependent electric field, similar to the dynamical Casimir effect in which real particles are radiated from the vacuum due to the time-dependent boundary conditions. We also propose an experimental setup using a quantum LC circuit to detect this novel effect. We expect physical electric charges to appear on the capacitor plates when the system dimension is such that coherent Aharonov-Bohm phases can be maintained over macroscopically large distances.
Aharonov-Bohm oscillation modes in double-barrier nanorings
Zhu, Jia-Lin; Yu, Xiquan; Dai, Zhensheng; Hu, Xiao
2003-02-01
The energy spectrum and Aharonov-Bohm (AB) effect in a two-dimensional nanoring interrupted by two identical barriers are studied, and a way of labeling a state according to the node numbers of the wave function in the absence of magnetic flux is introduced. It is found that a magnetic flux φ can modify both the phase and amplitude of wave functions due to the presence of the barriers. AB oscillations are strongly affected by the double barriers, and there are two modes of strong AB oscillations, named O and X modes. The energy levels of O and X modes are occasionally degenerate at φ=0 and 0.5, respectively, and the corresponding wave functions of both degenerate states are localized and can be greatly modified by a small change of φ. The O mode of AB oscillations, which does not exist in the parallel double-barrier ring usually used in experiments, presents an interesting picture and suggests other related phenomena.
Aharonov-Bohm oscillation modes in double-barrier nanorings
International Nuclear Information System (INIS)
The energy spectrum and Aharonov-Bohm (AB) effect in a two-dimensional nanoring interrupted by two identical barriers are studied, and a way of labeling a state according to the node numbers of the wave function in the absence of magnetic flux is introduced. It is found that a magnetic flux φ can modify both the phase and amplitude of wave functions due to the presence of the barriers. AB oscillations are strongly affected by the double barriers, and there are two modes of strong AB oscillations, named O and X modes. The energy levels of O and X modes are occasionally degenerate at φ=0 and 0.5, respectively, and the corresponding wave functions of both degenerate states are localized and can be greatly modified by a small change of φ. The O mode of AB oscillations, which does not exist in the parallel double-barrier ring usually used in experiments, presents an interesting picture and suggests other related phenomena
Fingerprints of Majorana Bound States in Aharonov-Bohm Geometry
Tripathi, Krashna Mohan; Das, Sourin; Rao, Sumathi
2016-04-01
We study a ring geometry, coupled to two normal metallic leads, which has a Majorana bound state (MBS) embedded in one of its arms and is threaded by Aharonov-Bohm (A B ) flux ϕ . We show that by varying the A B flux, the two leads go through resonance in an anticorrelated fashion while the resonance conductance is quantized to 2 e2/h . We further show that such anticorrelation is completely absent when the MBS is replaced by an Andreev bound state (ABS). Hence this anti-correlation in conductance when studied as a function of ϕ provides a unique signature of the MBS which cannot be faked by an ABS. We contrast the phase sensitivity of the MBS and ABS in terms of tunneling conductances. We argue that the relative phase between the tunneling amplitude of the electrons and holes from either lead to the level (MBS or ABS), which is constrained to 0 ,π for the MBS and unconstrained for the ABS, is responsible for this interesting contrast in the A B effect between the MBS and ABS.
Aharonov–Bohm interference in topological insulator nanoribbons
Peng, Hailin
2009-12-13
Topological insulators represent unusual phases of quantum matter with an insulating bulk gap and gapless edges or surface states. The two-dimensional topological insulator phase was predicted in HgTe quantum wells and confirmed by transport measurements. Recently, Bi2 Se3 and related materials have been proposed as three-dimensional topological insulators with a single Dirac cone on the surface, protected by time-reversal symmetry. The topological surface states have been observed by angle-resolved photoemission spectroscopy experiments. However, few transport measurements in this context have been reported, presumably owing to the predominance of bulk carriers from crystal defects or thermal excitations. Here we show unambiguous transport evidence of topological surface states through periodic quantum interference effects in layered single-crystalline Bi2 Se3 nanoribbons, which have larger surface-to-volume ratios than bulk materials and can therefore manifest surface effects. Pronounced Aharonov-Bohm oscillations in the magnetoresistance clearly demonstrate the coherent propagation of two-dimensional electrons around the perimeter of the nanoribbon surface, as expected from the topological nature of the surface states. The dominance of the primary h/e oscillation, where h is Plancks constant and e is the electron charge, and its temperature dependence demonstrate the robustness of these states. Our results suggest that topological insulator nanoribbons afford promising materials for future spintronic devices at room temperature.
Does Bohm's Quantum Force Have a Classical Origin?
Lush, David C.
2016-08-01
In the de Broglie-Bohm formulation of quantum mechanics, the electron is stationary in the ground state of hydrogenic atoms, because the quantum force exactly cancels the Coulomb attraction of the electron to the nucleus. In this paper it is shown that classical electrodynamics similarly predicts the Coulomb force can be effectively canceled by part of the magnetic force that occurs between two similar particles each consisting of a point charge moving with circulatory motion at the speed of light. Supposition of such motion is the basis of the Zitterbewegung interpretation of quantum mechanics. The magnetic force between two luminally-circulating charges for separation large compared to their circulatory motions contains a radial inverse square law part with magnitude equal to the Coulomb force, sinusoidally modulated by the phase difference between the circulatory motions. When the particles have equal mass and their circulatory motions are aligned but out of phase, part of the magnetic force is equal but opposite the Coulomb force. This raises a possibility that the quantum force of Bohmian mechanics may be attributable to the magnetic force of classical electrodynamics. It is further shown that relative motion between the particles leads to modulation of the magnetic force with spatial period equal to the de Broglie wavelength.
Time-dependent Aharonov-Bohm effect on the noncommutative space
Ma, Kai; Yang, Huan-Xiong
2016-01-01
We study the time-dependent Aharonov-Bohm effect on the noncommutative space. Because there is no net Aharonov-Bohm phase shift in the time-dependent case on the commutative space, therefore tiny deviation from zero indicates new physics. Based on the Seiberg-Witten map we obtained the gauge invariant and Lorentz covariant Aharonov-Bohm phase shift on noncommutative space in general case. We find there are two kinds of contributions: momentum-dependent and momentum-independent corrections. For the momentum-dependent correction, there is a cancellation between the magnetic and electric phase shifts, just like the case on the commutative space. However, there is a non-trivial contribution in the momentum-independent correction. This is true for both the time-independent and time-dependent Aharonov-Bohm effects on the noncommutative space. However, for the time-dependent Aharonov-Bohm effect, there is no overwhelming background which exists on both commutative and noncommutative space for the time-independent Ah...
Analytical and Numerical Study of the Aharonov--Bohm Effect in 3D and 4D Abelian Higgs Model
Chernodub, M. N.; Gubarev, F. V.; Polikarpov, M.I.
1996-01-01
We discuss the Aharonov--Bohm effect in three and four dimensional non--compact lattice Abelian Higgs model. We show analytically that this effect leads to the long--range Coulomb interaction of the charged particles, which is confining in three dimensions. The Aharonov--Bohm effect is found in numerical calculations in 3D Abelian Higgs model.
Spin-spin correlations of entangled qubit pairs in the Bohm interpretation of quantum mechanics
Ramsak, A
2012-01-01
A general entangled qubit pair is analyzed in the de Broglie-Bohm formalism corresponding to two spin-1/2 quantum rotors. Several spin-spin correlators of Bohm's hidden variables are analyzed numerically and a detailed comparison with results obtained by standard quantum mechanics is outlined. In addition to various expectation values the Bohm interpretation allows also a study of the corresponding probability distributions, which enables a novel understanding of entangled qubit dynamics. In particular, it is shown how the angular momenta of two qubits in this formalism can be viewed geometrically and characterized by their relative angles. For perfectly entangled pairs, for example, a compelling picture is given, where the qubits exhibit a unison precession making a constant angle between their angular momenta. It is also demonstrated that the properties of standard quantum mechanical spin-spin correlators responsible for the violation of Bell's inequalities are identical to their counterparts emerging from ...
Time-dependent Aharonov-Bohm Hamiltonian and admissibility criteria of quantum wave functions
International Nuclear Information System (INIS)
Self-adjointness of the time-independent Aharonov-Bohm Hamiltonians is shown to allow a continuous family of different dynamics including those following from Pauli's criterion of rotational invariance, Aharonov-Bohm criterion of single valuedness and a version of Pauli's criterion appropriate to cylindrical symmetry suggested by Henneberger. A time-dependent flux F(t) linking the Aharonov-Bohm solenoid leads to the time-dependent AB Hamiltonian. Explicit solutions in cases with and without inaccessible regions for the charged particle rule out applicability of both versions of the Pauli criterion. The solutions contain one time-independent parameter α, integer values of which correspond to single-valued wave functions. Any real (integer or noninteger) value of α is allowed. Charge and current densities depend on α and F(t) only through the combination changing the flux during an experiment can be understood as local effects of the electric field inevitably associated with changing magnetic flux
Quantum motion in superposition of Aharonov-Bohm with some additional electromagnetic fields
International Nuclear Information System (INIS)
The structure of additional electromagnetic fields to the Aharonov-Bohm field, for which the Schroedinger, Klein-Gordon, and Dirac equations can be solved exactly are described and the corresponding exact solutions are found. It is demonstrated that aside from the known cases (a constant and uniform magnetic field that is parallel to the Aharonov-Bohm solenoid, a static spherically symmetrical electric field, and the field of a magnetic monopole), there are broad classes of additional fields. Among these new additional fields we have physically interesting electric fields acting during a finite time or localized in a restricted region of space. There are additional time-dependent uniform and isotropic electric fields that allow exact solutions of the Schroedinger equation. In the relativistic case there are additional electric fields propagating along the Aharonov-Bohm solenoid with arbitrary electric pulse shape.
Tunable dynamical channel blockade in double-dot Aharonov-Bohm interferometers
Urban, Daniel; König, Jürgen
2008-01-01
We study electronic transport through an Aharonov-Bohm interferometer with single-level quantum dots embedded in the two arms. The full counting statistics in the shot-noise regime is calculated to first order in the tunnel-coupling strength. The interplay of interference and charging energy in the dots leads to a dynamical channel blockade that is tunable by the magnetic flux penetrating the Aharonov-Bohm ring. We find super-Poissonian behavior with diverging second and higher cumulants when...
Internal frame dragging and a global analog of the Aharonov-Bohm effect
March-Russell, John(Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford, OX1 3NP, U.K.); Preskill, John; Wilczek, Frank
1992-01-01
It is shown that the breakdown of a global symmetry group to a discrete subgroup can lead to analogs of the Aharonov-Bohm effect. At sufficiently low momentum transfer, the cross section for scattering of a particle with nontrivial Z2 charge off a global vortex is almost equal to (but definitely different from) maximal Aharonov-Bohm scattering; the effect goes away at large momentum transfer. The scattering of a spin-1/2 particle off a magnetic vortex provides an amusing experimentally realiz...
Spin-dependent transport through quantum-dot aharonov-bohm interferometers
Hiltscher B.; Governale M.; Konig J
2010-01-01
We study the influence of spin polarization on the degree of coherence of electron transport through interacting quantum dots. To this end, we identify transport regimes in which the degree of coherence can be related to the visibility of the Aharonov-Bohm oscillations in the current through a quantum-dot Aharonov-Bohm interferometer with one normal and one ferromagnetic lead. For these regimes, we calculate the visibility and, thus, the degree of coherence, as a function of the degree of spi...
The Crucial Role of Inert Source in the Magnetic Aharonov-Bohm Effect
Comay, E.
2009-01-01
The role of the inert magnetic source used in the Tonomura experiment that has confirmed the magnetic Aharonov-Bohm effect is discussed. For this purpose, an analysis of a thought experiment is carried out. Here the permanent magnet is replaced by a classical source which is made of an ideal coil. A detailed calculation of this noninert source proves that in this case the effect disappears. This outcome provides another support for the crucial role of an inert source in the Aharonov-Bohm effe...
Aharonov-Bohm oscillations in a mesoscopic ring with a quantum dot
Levy Yeyati, Alfredo; Buttiker, Markus
1995-01-01
We present an analysis of the Aharonov-Bohm oscillations for a mesoscopic ring with a quantum dot inserted in one of its arms. It is shown that microreversibility demands that the phase of the Aharonov-Bohm oscillations changes {\\it abruptly} when a resonant level crosses the Fermi energy. We use the Friedel sum rule to discuss the conservation of the parity of the oscillations at different conductance peaks. Our predictions are illustrated with the help of a simple one channel model that per...
Free and bound spin-polarized fermions in the fields of Aharonov--Bohm kind
Khalilov, V. R.; Mamsurov, I. V.; Eun, Lee Ki
2010-01-01
The scattering of electrons by an Aharonov--Bohm field is considered from the viewpoint of quantum-mechanical problem of constructing a self-adjoint Hamiltonian for the Pauli equation. The correct domain for the self-adjoint Hamiltonian, which takes into account explicitly the electron spin is found. A one-parameter self-adjoint extension of the Hamiltonian for spin-polarized electrons in the Aharonov--Bohm field is selected. The correct domain of the self-adjoint Hamiltonian can contain regu...
Stokes' theorem, gauge symmetry and the time-dependent Aharonov-Bohm effect
International Nuclear Information System (INIS)
Stokes' theorem is investigated in the context of the time-dependent Aharonov-Bohm effect—the two-slit quantum interference experiment with a time varying solenoid between the slits. The time varying solenoid produces an electric field which leads to an additional phase shift which is found to exactly cancel the time-dependent part of the usual magnetic Aharonov-Bohm phase shift. This electric field arises from a combination of a non-single valued scalar potential and/or a 3-vector potential. The gauge transformation which leads to the scalar and 3-vector potentials for the electric field is non-single valued. This feature is connected with the non-simply connected topology of the Aharonov-Bohm set-up. The non-single valued nature of the gauge transformation function has interesting consequences for the 4-dimensional Stokes' theorem for the time-dependent Aharonov-Bohm effect. An experimental test of these conclusions is proposed
Interference between the Aharonov-Bohm and Aharonov-Casher effects
International Nuclear Information System (INIS)
After a discussion of the principles of the Aharonov-Bohm (AB) and Aharonov-Casher (AC) effects, the possibility of observing the interference between them is discussed. The implications of the AB and AC effects for anyon physics are also considered. (author) 8 refs., 3 figs
Stokes' theorem, gauge symmetry and the time-dependent Aharonov-Bohm effect
Energy Technology Data Exchange (ETDEWEB)
Macdougall, James, E-mail: jbm34@mail.fresnostate.edu; Singleton, Douglas, E-mail: dougs@csufresno.edu [Department of Physics, California State University Fresno, Fresno, California 93740-8031 (United States)
2014-04-15
Stokes' theorem is investigated in the context of the time-dependent Aharonov-Bohm effect—the two-slit quantum interference experiment with a time varying solenoid between the slits. The time varying solenoid produces an electric field which leads to an additional phase shift which is found to exactly cancel the time-dependent part of the usual magnetic Aharonov-Bohm phase shift. This electric field arises from a combination of a non-single valued scalar potential and/or a 3-vector potential. The gauge transformation which leads to the scalar and 3-vector potentials for the electric field is non-single valued. This feature is connected with the non-simply connected topology of the Aharonov-Bohm set-up. The non-single valued nature of the gauge transformation function has interesting consequences for the 4-dimensional Stokes' theorem for the time-dependent Aharonov-Bohm effect. An experimental test of these conclusions is proposed.
Eigenvalue estimates for the Aharonov-Bohm operator in a domain
Frank, Rupert L.; Hansson, Anders
2007-01-01
We prove semi-classical estimates on moments of eigenvalues of the Aharonov-Bohm operator in bounded two-dimensional domains. Moreover, we present a counterexample to the generalized diamagnetic inequality which was proposed by Erdos, Loss and Vougalter. Numerical studies complement these results.
Stokes' theorem, gauge symmetry and the time-dependent Aharonov-Bohm effect
Macdougall, James
2013-01-01
Stokes' theorem is investigated in the context of the time-dependent Aharonov-Bohm effect -- the two-slit quantum interference experiment with a time varying solenoid between the slits. The time varying solenoid produces an electric field which leads to an additional phase shift which is found to exactly cancel the time-dependent part of the usual magnetic Aharonov-Bohm phase shift. This electric field arises from a combination of a non-single valued scalar potential and/or a 3-vector potential. The gauge transformation which leads to the scalar and 3-vector potentials for the electric field is non-single valued. This feature is connected with the non-simply connected topology of the Aharonov-Bohm set-up. The non-single valued nature of the gauge transformation function has interesting consequences for the 4-dimensional Stokes' theorem for the time-dependent Aharonov-Bohm effect. An experimental test of these conclusions is proposed.
Duality in the Aharonov-Casher and Aharonov-Bohm effects
International Nuclear Information System (INIS)
A neutral particle with a magnetic moment interacts with a charged particle. Such an interaction is invariant under the interchange of the particles. This interchangeability or duality of the particles elucidates subtleties of the Aharonov-Bohm and Aharonov-Casher effects, including whether and how these two effects are themselves dual.
Revisiting the Marton, Simpson, and Suddeth experimental confirmation of the Aharonov-Bohm effect
Macdougall, James; Vagenas, Elias C
2015-01-01
We perform an "archeological" study of one of the original experiments used as evidence for the static, time-independent Aharonov-Bohm effect. Since the experiment in question [L. Marton, J. A. Simpson, and J. A. Suddeth, Rev. Sci. Instr. 25, 1099 (1954)] involved a time varying magnetic field we show that there are problems with the explanation of this experiment as a confirmation of the static Aharonov-Bohm effect -- specifically the previous analysis ignored the electric field which arises in conjunction with a time-varying magnetic flux. We further argue that the results of this experiment do in fact conform exactly to the recent prediction [D. Singleton and E. Vagenas, Phys. Lett. B723, 241 (2013); J. MacDougall and D. Singleton, J. Math. Phys. 55, 042101 (2014)] of a cancellation between the magnetic and electric phase shifts for the time-dependent Aharonov-Bohm effect. To resolve this issue a new time-dependent Aharonov-Bohm experiment is called for.
Event-by-event simulation of Einstein-Podolsky-Rosen-Bohm experiments
Zhao, Shuang; De Raedt, Hans; Michielsen, Kristel
2008-01-01
We construct an event-based computer simulation model of the Einstein-Podolsky-Rosen-Bohm experiments with photons. The algorithm is a one-to-one copy of the data gathering and analysis procedures used in real laboratory experiments. We consider two types of experiments, those with a source emitting
Gravitational Aharonov–Bohm effect due to noncommutative BTZ black hole
Energy Technology Data Exchange (ETDEWEB)
Anacleto, M.A., E-mail: anacleto@df.ufcg.edu.br; Brito, F.A., E-mail: fabrito@df.ufcg.edu.br; Passos, E., E-mail: passos@df.ufcg.edu.br
2015-04-09
In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov-Bohm effect due to spacetime noncommutativity.
Gravitational Aharonov–Bohm effect due to noncommutative BTZ black hole
Directory of Open Access Journals (Sweden)
M.A. Anacleto
2015-04-01
Full Text Available In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov–Bohm effect due to spacetime noncommutativity.
Gravitational Aharonov–Bohm effect due to noncommutative BTZ black hole
International Nuclear Information System (INIS)
In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov-Bohm effect due to spacetime noncommutativity
Gravitational Aharonov-Bohm effect due to noncommutative BTZ black hole
Anacleto, M A; Passos, E
2014-01-01
In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov-Bohm effect due to spacetime noncommutativity
Gravitational Aharonov–Bohm effect due to noncommutative BTZ black hole
M.A. Anacleto; Brito, F. A.; E. Passos
2015-01-01
In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov–Bohm effect due to spacetime noncommutativity.
Gravitational Aharonov-Bohm effect due to noncommutative BTZ black hole
Anacleto, M. A.; Brito, F. A.; Passos, E.
2015-04-01
In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov-Bohm effect due to spacetime noncommutativity.
Aharonov-Bohm effects on bright and dark excitons in carbon nanotubes
International Nuclear Information System (INIS)
A short-range part of the Coulomb interaction causes splitting and shift of excitons due to exchange interaction and mixing between different valleys in semiconducting carbon nanotubes. In the absence of a magnetic flux only a single exciton is optically active (bright) and all others are inactive (dark). Two bright excitons appear in the presence of an Aharonov- Bohm magnetic flux
Free and bound spin-polarized fermions in the fields of Aharonov--Bohm kind
Khalilov, V R; Eun, Lee Ki
2010-01-01
The scattering of electrons by an Aharonov--Bohm field is considered from the viewpoint of quantum-mechanical problem of constructing a self-adjoint Hamiltonian for the Pauli equation. The correct domain for the self-adjoint Hamiltonian, which takes into account explicitly the electron spin is found. A one-parameter self-adjoint extension of the Hamiltonian for spin-polarized electrons in the Aharonov--Bohm field is selected. The correct domain of the self-adjoint Hamiltonian can contain regular and singular (at the point ${\\bf r}=0$) square-integrable functions on the half-line with measure $rdr$. We argue that the physical reason of the existence of singular functions is the additional attractive potential, which appear due to the interaction between the spin magnetic moment of fermion and Aharonov--Bohm magnetic field. The scattering amplitude and cross section are obtained for spin-polarized electrons scattered by the Aharonov--Bohm field. It is shown that in some range of the extension parameter there ap...
The bound-state Aharonov-Bohm effect around a cosmic string revisited
International Nuclear Information System (INIS)
In this Letter we observe that the self-adjoint extension of the Hamiltonian of a particle moving around a cosmic string gives rise to a gravitational analogue of the bound-state Aharonov-Bohm effect without the need of confining walls
Bohmian mechanics and quantum theory an appraisal
Goldstein, Sheldon; Cushing, James T
1996-01-01
We are often told that quantum phenomena demand radical revisions of our scientific world view and that no physical theory describing well defined objects, such as particles described by their positions, evolving in a well defined way, let alone deterministically, can account for such phenomena. The great majority of physicists continue to subscribe to this view, despite the fact that just such a deterministic theory, accounting for all of the phe nomena of nonrelativistic quantum mechanics, was proposed by David Bohm more than four decades ago and has arguably been around almost since the inception of quantum mechanics itself. Our purpose in asking colleagues to write the essays for this volume has not been to produce a Festschrift in honor of David Bohm (worthy an undertaking as that would have been) or to gather together a collection of papers simply stating uncritically Bohm's views on quantum mechanics. The central theme around which the essays in this volume are arranged is David Bohm's vers...
Eckle, H. -P.; Johannesson, H; Stafford, C. A.
2000-01-01
We study the persistent currents induced by both the Aharonov-Bohm and Aharonov-Casher effects in a one-dimensional mesoscopic ring coupled to a side-branch quantum dot at Kondo resonance. For privileged values of the Aharonov-Bohm-Casher fluxes, the problem can be mapped onto an integrable model, exactly solvable by a Bethe ansatz. In the case of a pure magnetic Aharonov-Bohm flux, we find that the presence of the quantum dot has no effect on the persistent current. In contrast, the Kondo re...
Bais, F A
1995-01-01
In these lecture notes, we present a self-contained discussion of planar gauge theories broken down to some finite residual gauge group H via the Higgs mechanism. The main focus is on the discrete H gauge theory describing the long distance physics of such a model. The spectrum features global H charges, magnetic vortices and dyonic combinations. Due to the Aharonov-Bohm effect, these particles exhibit topological interactions. Among other things, we review the Hopf algebra related to this discrete H gauge theory, which provides an unified description of the spin, braid and fusion properties of the particles in this model. Exotic phenomena such as flux metamorphosis, Alice fluxes, Cheshire charge, (non)abelian braid statistics, the generalized spin-statistics connection and nonabelian Aharonov-Bohm scattering are explained and illustrated by representative examples. Preface: Broken symmetry revisited, 1 Basics: 1.1 Introduction, 1.2 Braid groups, 1.3 Z_N gauge theory, 1.3.1 Coulomb screening, 1.3.2 Survival o...
Kao, W. F.; Kao, Y. M.; Lin, D. H.
2002-01-01
A useful and universal formula for the expectation value of the radial operator in the presence of the Aharonov-Bohm flux and the Coulomb Field is established. We find that the expectation value $$ $(-\\infty \\leq \\lambda \\leq \\infty)$ is greatly affected due to the non-local effect of the magnetic flux although the Aharonov-Bohm flux does not have any dynamical significance in classical mechanics. In particular, the quantum fluctuation increases in the presence of the magnetic f...
Scattering of spin 1/2 particles by the 2+1 dimensional noncommutative Aharonov-Bohm potential
Ferrari, A. F.; Gomes, M; Stechhahn, C. A.
2007-01-01
In this work we study modifications in the Aharonov-Bohm effect for relativistic spin 1/2 particles due to the noncommutativity of spacetime in $2 + 1$ dimensions. The noncommutativity gives rise to a correction to the Aharonov-Bohm potential which is highly singular at the origin, producing divergences in a perturbative expansion around the usual solution of the free Dirac equation. This problem is surmounted by using a perturbative expansion around the exact solution of the \\textit{commutat...
Villalba, Victor M.
1994-01-01
In the present article we analyze the bound states of an electron in a Coulomb field when an Aharonov-Bohm field as well as a magnetic Dirac monopole are present. We solve, via separation of variables, the Schr\\"odinger equation in spherical coordinates and we show how the Hydrogen energy spectrum depends on the Aharonov-Bohm and the magnetic monopole strengths. In passing, the Klein-Gordon equation is solved.
Energy Technology Data Exchange (ETDEWEB)
Zhang Jianzu [Institute for Theoretical Physics, East China University of Science and Technology, Box 316, Shanghai 200237 (China)], E-mail: jzzhang@ecust.edu.cn
2008-12-18
An induced fractional zero-point angular momentum of charged particles by the Bohm-Aharonov (BA) vector potential is realized via a modified combined trap. It explores a 'spectator' mechanism in this type of quantum effects: In the limit of the kinetic energy approaching one of its eigenvalues the BA vector potential alone cannot induce a fractional zero-point angular momentum at quantum mechanical level in the BA magnetic field-free region; But when there is a 'spectator' magnetic field the BA vector potential induces a fractional zero-point angular momentum. The 'spectator' does not contribute to such a fractional angular momentum, but plays essential role in guaranteeing non-trivial dynamics at quantum mechanical level in the required limit. This 'spectator' mechanism is significant in investigating the BA effects and related topics in both aspects of theory and experiment.
Quantum Theory of Strings in Abelian Higgs Model
Akhmedov, E. T.; Chernodub, M. N.; Polikarpov, M.I.; Zubkov, M.A.
1995-01-01
Starting from the Abelian Higgs field theory, we construct the theory of quantum Abrikosov--Nielsen--Olesen strings. It is shown that in four space -- time dimensions in the limit of infinitely thin strings, the conformal anomaly is absent, and the quantum theory exists. We also study an analogue of the Aharonov--Bohm effect: the corresponding topological interaction is proportional to the linking number of the string world sheet and the particle world trajectory. The creation operators of th...
Reply to "Comment on `Role of potentials in the Aharonov-Bohm effect' "
Vaidman, Lev
2015-08-01
The preceding Comment challenged my claim that potentials might be just auxiliary mathematical tools and that they are not necessary for explaining physical phenomena. The Comment did not confront my explanation without the potentials of the Aharonov-Bohm effects that appeared in the original article, but stated that I cannot apply this explanation for seven other examples. In my reply, using my method, I provide explanations of one of the examples, show that two other examples are not relevant, and agree that the remaining examples require further analysis. However, I argue that none of the examples provides robust counterexamples to my claim, similar to the original Aharonov-Bohm setups which were explained in my article, so the Comment does not refute my claim.
Conductance in an Aharonov—Bohm Interferometer with Parallel-Coupled Double Dots
International Nuclear Information System (INIS)
We present a theoretical study of the conductance in an Aharonov—Bohm interferometer containing two coupled quantum dots. The interdot tunneling divides the interferometer into two coupled subrings, where opposite magnetic fluxes are threaded separately while the net flux is kept zero. Using the Green function technique we derive the expression of the linear conductance. It is found that the Aharonov-Bohm effect still exists, and when the level of each dot is aligned, the exchange of the Fano and Breit–Wigner resonances in the conductance can be achieved by tuning the magnetic flux. When the two levels are mismatched the exchange may not happen. Further, for some specific asymmetric systems where the coupling strengths between the two dots and the leads are not equal, the flux can change the Fano resonance into an antiresonance, which is absent in symmetric systems
Graphene rings in magnetic fields: Aharonov–Bohm effect and valley splitting
International Nuclear Information System (INIS)
We study the conductance of mesoscopic graphene rings in the presence of a perpendicular magnetic field by means of numerical calculations based on a tight-binding model. First, we consider the magnetoconductance of such rings and observe the Aharonov–Bohm effect. We investigate different regimes of the magnetic flux up to the quantum Hall regime, where the Aharonov–Bohm oscillations are suppressed. Results for both clean (ballistic) and disordered (diffusive) rings are presented. Second, we study rings with smooth mass boundary that are weakly coupled to leads. We show that the valley degeneracy of the eigenstates in closed graphene rings can be lifted by a small magnetic flux, and that this lifting can be observed in the transport properties of the system
The time-dependent non-Abelian Aharonov-Bohm effect
Bright, Max
2015-01-01
In this article, we study the {\\it time-dependent} Aharonov-Bohm effect for non-Abelian gauge fields. We use two well known time-dependent solutions to the Yang-Mills field equations to investigate the Aharonov-Bohm phase shift. For both of the solutions, we find a cancellation between the phase shift coming from the non-Abelian "magnetic" field and the phase shift coming from the non-Abelian "electric" field, which inevitably arises in time-dependent cases. We compare and contrast this cancellation for the time-dependent non-Abelian case to a similar cancellation which occurs in the time-dependent Abelian case. We postulate that this cancellation occurs generally in time-dependent situations for both Abelian and non-Abelian fields.
Spin accumulation assisted by the Aharonov-Bohm-Fano effect of quantum dot structures.
Gong, Wei-Jiang; Han, Yu; Wei, Guo-Zhu; Du, An
2012-01-01
: We investigate the spin accumulations of Aharonov-Bohm interferometers with embedded quantum dots by considering spin bias in the leads. It is found that regardless of the interferometer configurations, the spin accumulations are closely determined by their quantum interference features. This is mainly manifested in the dependence of spin accumulations on the threaded magnetic flux and the nonresonant transmission process. Namely, the Aharonov-Bohm-Fano effect is a necessary condition to achieve the spin accumulation in the quantum dot of the resonant channel. Further analysis showed that in the double-dot interferometer, the spin accumulation can be detailedly manipulated. The spin accumulation properties of such structures offer a new scheme of spin manipulation. When the intradot Coulomb interactions are taken into account, we find that the electron interactions are advantageous to the spin accumulation in the resonant channel. PMID:22985404
Transmission through a quantum dot molecule embedded in an Aharonov-Bohm interferometer
Lovey, Daniel A.; Gomez, Sergio S.; Romero, Rodolfo H.
2011-01-01
We study theoretically the transmission through a quantum dot molecule embedded in the arms of an Aharonov-Bohm four quantum dot ring threaded by a magnetic flux. The tunable molecular coupling provides a transmission pathway between the interferometer arms in addition to those along the arms. From a decomposition of the transmission in terms of contributions from paths, we show that antiresonances in the transmission arise from the interference of the self-energy along different paths and th...
How the Test of Aharonov-Bohm Effect Was Initiated at Hitachi Laboratory
Osakabe, Nobuyuki
2014-01-01
I joined the Tonomura's team in 1980. Since then, I have seen his enthusiasm and creativity in science as a member of his team and later as director of the laboratory. I will discuss in this article how the industrially driven technologies met science at Hitachi Central Research Laboratory in the case of verification of the Aharonov-Bohm effect and other scientific achievements by Akira Tonomura.
Tunable Molecular Resonances of Double Quantum Dots Embedded in an Aharonov-Bohm Interferometer
Kang, Kicheon; Cho, Sam Young
2002-01-01
We investigate resonant tunneling through molecular states of coupled double quantum dots embedded in an Aharonov-Bohm (AB) interferometer. The conductance through the system consists of two resonances associated with the bonding and the antibonding quantum states. We predict that the two resonances are composed of a Breit-Wigner resonance and a Fano resonance, those widths and Fano factor depending on the AB phase very sensitively. Further, we point out that the bonding properties, such as t...
The Aharonov–Bohm effect in scattering of short-wavelength particles
International Nuclear Information System (INIS)
Quantum-mechanical scattering of nonrelativistic charged particles by a magnetic vortex of nonzero transverse size is considered. We show that the flux of the vortex serves as a gate for the strictly forward propagation of particles with short, as compared to the transverse size of the vortex, wavelengths; this effect is the same for a penetrable vortex as for an impenetrable one. A possibility for the experimental detection of the scattering Aharonov–Bohm effect is discussed. (paper)
Two impurity Kondo problem under Aharonov--Bohm and Aharonov--Casher Effects
Aono, Tomosuke
2006-01-01
We investigate electron transport under the two impurity Kondo problem with the Aharonov--Bohm and Aharonov--Casher effects. These interference effects induce the Ising-coupled Ruderman--Kittel--Kasuya--Yosida (RKKY) interaction. We discuss the inter- and intra-site spin conductance as well as charge conductance in the Kondo and the mixed-valence regimes using the slave boson mean field approximation.
Entanglement entropy as a witness of the Aharonov-Bohm effect in QFT
Arias, Raúl E; Casini, Horacio
2014-01-01
We study the dependence of the entanglement entropy with a magnetic flux, and show that the former quantity witnesses an Aharonov Bohm-like effect. In particular, we consider free charged scalar and Dirac fields living on a two dimensional cylinder and study how the entanglement entropy for a strip-like region on the surface of the cylinder is affected by a magnetic field enclosed by it.
Sharp asymptotic estimates for eigenvalues of Aharonov-Bohm operators with varying poles
Abatangelo, L; Felli, V.
2015-01-01
We investigate the behavior of eigenvalues for a magnetic Aharonov-Bohm operator with half-integer circulation and Dirichlet boundary conditions in a planar domain. We provide sharp asymptotics for eigenvalues as the pole is moving in the interior of the domain, approaching a zero of an eigenfunction of the limiting problem along a nodal line. As a consequence, we verify theoretically some conjectures arising from numerical evidences in preexisting literature. The proof relies on an Almgren-t...
Aharonov-Bohm scattering of neutral atoms with induced electric dipole moments
Audretsch, Juergen; Skarzhinsky, Vladimir
1998-01-01
We investigate the scattering of neutral polarizable atoms from an electrically charged wire placed in a homogeneous magnetic field. The atoms carry an induced electric dipole. The reflecting wire is discussed. We calculate the scattering amplitude and cross section the practically more important case that atoms are totally absorbed at the surface of the wire. If the magnetic field is present, there is a dominating Aharonov-Bohm peak in the forward direction followed by decreasing oscillation...
Aharonov-Bohm-Type Oscillations of Thermopower in a Quantum Dot Ring Geometry
Blanter, Ya. M.; Bruder, Christoph; Fazio, Rosario; Schoeller, Herbert
1996-01-01
We investigate Aharonov-Bohm-type oscillations of the thermopower of a quantum dot embedded in a ring for the case when the interaction between electrons can be neglected. The thermopower is shown to be strongly flux dependent, and typically the amplitude of oscillations exceeds the background value. It is also shown to be essentially dependent on the phase of the scattering matrix which is determined by the experimental geometry and is not known in the given experiment. Two procedures to com...
Reply to "Comment on "Aharonov-Casher and Scalar Aharonov-Bohm Topological Effects""
Ma, Kai; Dulat, Sayipjamal
2013-01-01
In this Reply we argue that (i) the Hamiltonian, Eq. (17) in our paper (Phys. Rev. Lett. 108, 070405 (2012)), is definitely Lorentz invariant; (ii) the conditions of generating topological Aharonov-Casher(AC) and Scalar Aharonov-Bohm (SAB) effects are essential and physically meaningful; (iii) the Hamiltonians both in Phys. Rev. Lett. 74, 2847 (1995) and arXiv:1311.4011 are not suitable to describe the polarized spinor particles.
Spin-dependent quantum transport through an Aharonov–Bohm structure spin splitter
International Nuclear Information System (INIS)
Using the tight-binding model approximation, this paper investigates theoretically spin-dependent quantum transport through an Aharonov–Bohm (AB) interferometer. An external magnetic field is applied to produce the spin-polarization and spin current. The AB interferometer, acting as a spin splitter, separates the opposite spin polarization current. By adjusting the energy and the direction of the magnetic field, large spin-polarized current can be obtained. (condensed matter: structure, mechanical and thermal properties)
Coupling of Aharonov-Bohm and Aharonov-Casher effects at different particle spins
International Nuclear Information System (INIS)
Coupling of Aharonov-Bohm and Aharonov-Casher topological effects is studied depending on the spin of moving particle and its orientation. Duality of wave functions occurs only at the absence of spin precession, that is, at a certain, maximal by the absolute value of its projection on the normal to the motion plane. Generalization for particles both with charge and anomalous magnetic moment is studied. 12 refs
Polarized excitons in nanorings and the `optical' Aharonov-Bohm effect
Govorov, A. O.; Ulloa, S. E.; Karrai, K.; Warburton, R. J.
2002-01-01
The quantum nature of matter lies in the wave function phases that accumulate while particles move along their trajectories. A prominent example is the Aharonov-Bohm phase, which has been studied in connection with the conductance of nanostructures. However, optical response in solids is determined by neutral excitations, for which no sensitivity to magnetic flux would be expected. We propose a new mechanism for the topological phase of a neutral particle, a polarized exciton confined to a se...
Semenov, Andrew G.; Zaikin, Andrei D.
2010-01-01
We investigate the effect of electron-electron interactions on Aharonov-Bohm (AB) current oscillations in nanorings formed by a chain of metallic quantum dots. We demonstrate that electron-electron interactions cause electron dephasing thereby suppressing the amplitude of AB oscillations at all temperatures down to T=0. The crossover between thermal and quantum dephasing is found to be controlled by the ring perimeter. Our predictions can be directly tested in future experiments.
Tadić, M.; Čukarić, N.; Arsoski, V.; Peeters, F. M.
2010-01-01
The exciton states in strained (In,Ga)As nanorings embedded in a GaAs matrix are computed. The strain distribution is extracted from the continuum mechanical model, and the exact diagonalization approach is employed to compute the exciton states. Weak oscillations of the ground exciton state energy with the magnetic field normal to the ring are an expression of the excitonic Aharonov-Bohm effect. Those oscillations arise from anticrossings between the ground and the second exciton state and c...
Semenov, Andrew G.; Zaikin, Andrei D.
2009-01-01
We investigate the effect of electron-electron interactions on Aharonov-Bohm (AB) current oscillations in nanorings formed by a chain of metallic quantum dots. We demonstrate that electron-electron interactions cause electron dephasing thereby suppressing the amplitude of AB oscillations at all temperatures down to T=0. The crossover between thermal and quantum dephasing is found to be controlled by the ring perimeter. Our predictions can be directly tested in future experiments.
Event-by-event simulation of Einstein-Podolsky-Rosen-Bohm experiments
Zhao, Shuang; De Raedt, Hans; Michielsen, Kristel
2008-01-01
We construct an event-based computer simulation model of the Einstein-Podolsky-Rosen-Bohm experiments with photons. The algorithm is a one-to-one copy of the data gathering and analysis procedures used in real laboratory experiments. We consider two types of experiments, those with a source emitting photons with opposite but otherwise unpredictable polarization and those with a source emitting photons with fixed polarization. In the simulation, the choice of the direction of polarization meas...
Observation of Scalar Aharonov-Bohm Effect with Longitudinally Polarized Neutrons
Lee, W. -T.; Motrunich, O.; Allman, B. E.; Werner, S. A.
1998-01-01
We have carried out a neutron interferometry experiment using longitudinally polarized neutrons to observe the scalar Aharonov-Bohm effect. The neutrons inside the interferometer are polarized parallel to an applied pulsed magnetic field B(t). The pulsed B field is spatially uniform so it exerts no force on the neutrons. Its direction also precludes the presence of any classical torque to change the neutron polarization.
Spin-dependent quantum transport through an Aharonov-Bohm structure spin splitter
Institute of Scientific and Technical Information of China (English)
Li Yu-Xian
2008-01-01
Using the tight-binding model approximation, this paper investigates theoretically spin-dependent quantum trans-port through an Aharonov-Bohm (AB) interferometer. An external magnetic field is applied to produce the spin-polarization and spin current. The AB interferometer, acting as a spin splitter, separates the opposite spin polarization current. By adjusting the energy and the direction of the magnetic field, large spin-polarized current can be obtained.
Asymmetry of the Aharonov-Bohm diffraction pattern and Ehrenfest's theorem
International Nuclear Information System (INIS)
The electron diffraction pattern for two-slits with magnetic flux confined to an inaccessible region between them is calculated. The Aharonov-Bohm effect gives a diffraction pattern which is asymmetric but with a symmetric envelope. In general, both expected displacement and kinetic momentum of the electron are nonzero as a consequence of the asymmetry. Nevertheless Ehrenfest's theorems and the conservation of momentum are satisfied. (author)
Aharonov-Bohm effect for a fermion field in the acoustic black hole background
Anacleto, M A; Mohammadi, A; Passos, E
2016-01-01
In this paper we consider the dynamics of a massive spinor field in the background of the acoustic black hole spacetime and then compute the differential cross section through the use of the partial wave approach. We show that an effect similar to the gravitational Aharonov-Bohm effect occurs for massive fermion fields moving in this effective metric. We discuss the limiting cases and compare the results with the bosonic case.
Remark on the Connectedness of Space in the Experimental Devices of Aharonov-Bohm Effect
Institute of Scientific and Technical Information of China (English)
QIAN Shang-Wu; GU Zhi-Yu
2003-01-01
This article shows that in Aharonov-Bohm (AB) effect arrangements, the electron wave propagation spaceis doubly connected for two real coherent sources, and simply connected under certain condition for two virtual coherentsources, and all known AB experiments belong to the latter case. By the Feynman path integral method, we show thatin the former case there is no AB effect, whereas in the latter case there is.
The Sagnac Phase Shift suggested by the Aharonov-Bohm effect for relativistic matter beams
Rizzi, Guido; Ruggiero, Matteo Luca
2003-01-01
The phase shift due to the Sagnac Effect, for relativistic matter beams counter-propagating in a rotating interferometer, is deduced on the bases of a a formal analogy with the the Aharonov-Bohm effect. A procedure outlined by Sakurai, in which non relativistic quantum mechanics and newtonian physics appear together with some intrinsically relativistic elements, is generalized to a fully relativistic context, using the Cattaneo's splitting technique. This approach leads to an exact derivation...
Axial anomaly in the presence of the Aharonov-Bohm gauge field
International Nuclear Information System (INIS)
The axial anomaly for Euclidean Dirac fermions in the presence of a background Aharonov-Bohm gauge potential was computed. The non-perturbative result depends on the self-adjoint extensions of the Dirac operator. The role of the quantum mechanical parameters involved in the expression for the axial anomaly is discussed. A derivation of the effective action by means of the stereographic projection is also considered. (authors). 14 refs
Geometric phases in quantum mechanics and the dual Aharonov-Bohm effect
International Nuclear Information System (INIS)
Full text: In the year of 1959, Y. Aharonov and D. Bohm published a paper discussing the importance of the electromagnetic potentials in quantum mechanics, not only as a mathematical tool but as an object with physical significance. In this paper they propose an experiment in which a measurable phase change can be observed in the wavefunction of the electron passing by a long thin solenoid due to the presence of the magnetic potential, even in the absence of magnetic fields. Since then, the effect became known as the Aharonov-Bohm (AB) effect. Although it was not widely discussed at the time of the above publication, the AB effect can be understood as a specific case of a broader class of phenomena generally known as geometric phases. A paper was published in 1984 by the british physicist Michael Berry bringing about a widespread discussion on the importance of geometric phases and their appearance and applications in a great number of physical systems and in technologies such as topological quantum computation, for instance. In this work we discuss the appearance of geometric phases in both adiabatic, as discussed by Berry, and general evolution of quantum systems. Some modern applications are presented and the approach of geometrical phases is used to study some proposed implementations of the dual Aharonov-Bohm effect, built upon duality transformations on Maxwell's Equations. (author)
Bound states of massive fermions in the Aharonov--Bohm-like fields
Khalilov, V R
2014-01-01
Bound states of massive fermions in the Aharonov-Bohm like fields have analytically been studied. The Hamiltonians with the Aharonov--Bohm like potentials are essentially singular and therefore require specification of a one-parameter self-adjoint extension. We construct self-adjoint Dirac Hamiltonians with the Aharonov-Bohm (AB) potential in 2+1 dimensions that are specified by boundary conditions at the origin. It is of interest that for some range of extension parameter the AB potential can bind relativistic charged massive fermions. The bound-state energy is determined by the AB magnetic flux and depends upon fermion spin and extension parameter; it is a periodical function of the magnetic flux. We also construct self-adjoint Hamiltonians for the so-called Aharonov-Casher (AC) problem, show that nonrelativistic neutral massive fermions can be bound by the Aharonov-Casher background, determine the range of extension parameter in which fermion bound states exist and find their energies as well as wave funct...
Effects of nongauge potentials on the spin-1/2 Aharonov-Bohm problem
International Nuclear Information System (INIS)
Some recent work has attempted to show that the singular solutions which are known to occur in the Dirac description of spin-1/2 Aharonov-Bohm scattering can be eliminated by the inclusion of strongly repulsive potentials inside the flux tube. It is shown here that these calculations are generally unreliable since they necessarily require potentials which lead to the occurrence of Klein's paradox. To avoid that difficulty the problem is solved within the framework of the Galilean spin-1/2 wave equation which is free of that particular complication. It is then found that the singular solutions can be eliminated provided that the nongauge potential is made energy dependent. The effect of the inclusion of a Coulomb potential is also considered with the result being that the range of flux parameter for which singular solutions are allowed is only one-half as great as in the pure Aharonov-Bohm limit. Expressions are also obtained for the binding energies which can occur in the combined Aharonov-Bohm-Coulomb system
Exotic electron states and tunable magneto-transport in a fractal Aharonov–Bohm interferometer
Energy Technology Data Exchange (ETDEWEB)
Nandy, Atanu, E-mail: atanunandy1989@gmail.com; Pal, Biplab, E-mail: biplabpal@klyuniv.ac.in; Chakrabarti, Arunava, E-mail: arunava_chakrabarti@yahoo.co.in
2014-08-28
A Sierpinski gasket fractal network model is studied in respect of its electronic spectrum and magneto-transport when each ‘arm’ of the gasket is replaced by a diamond shaped Aharonov–Bohm interferometer, threaded by a uniform magnetic flux. Within the framework of a tight binding model for non-interacting, spinless electrons and a real space renormalization group method we unravel a class of extended and localized electronic states. In particular, we demonstrate the existence of extreme localization of electronic states at a special finite set of energy eigenvalues, and an infinite set of energy eigenvalues where the localization gets ‘delayed’ in space (staggered localization). These eigenstates exhibit a multitude of localization areas. The two terminal transmission coefficient and its dependence on the magnetic flux threading each basic Aharonov–Bohm interferometer is studied in details. Sharp switch on–switch off effects that can be tuned by controlling the flux from outside, are discussed. Our results are analytically exact. - Highlights: • Electronic spectrum of an Aharonov–Bohm interferometer is studied in details. • A staggering effect in the electron localization is observed. • An external magnetic flux leads to an extreme localization of electronic states. • A flux controlled switch on–switch off effect in the magneto-transport is shown.
Exotic electron states and tunable magneto-transport in a fractal Aharonov–Bohm interferometer
International Nuclear Information System (INIS)
A Sierpinski gasket fractal network model is studied in respect of its electronic spectrum and magneto-transport when each ‘arm’ of the gasket is replaced by a diamond shaped Aharonov–Bohm interferometer, threaded by a uniform magnetic flux. Within the framework of a tight binding model for non-interacting, spinless electrons and a real space renormalization group method we unravel a class of extended and localized electronic states. In particular, we demonstrate the existence of extreme localization of electronic states at a special finite set of energy eigenvalues, and an infinite set of energy eigenvalues where the localization gets ‘delayed’ in space (staggered localization). These eigenstates exhibit a multitude of localization areas. The two terminal transmission coefficient and its dependence on the magnetic flux threading each basic Aharonov–Bohm interferometer is studied in details. Sharp switch on–switch off effects that can be tuned by controlling the flux from outside, are discussed. Our results are analytically exact. - Highlights: • Electronic spectrum of an Aharonov–Bohm interferometer is studied in details. • A staggering effect in the electron localization is observed. • An external magnetic flux leads to an extreme localization of electronic states. • A flux controlled switch on–switch off effect in the magneto-transport is shown
International Nuclear Information System (INIS)
We show that the Hamiltonian H and the helicity operator Λ of a Dirac particle moving in two dimensions in the presence of an infinitely thin magnetic flux tube each admit a four-parameter family of self-adjoint extensions. Each extension is in one-to-one correspondence with the boundary conditions (BCs) to be satisfied by the eigenfunctions at the origin. Although the actions of these two operators commute before specification of BCs, to ensure helicity conservation it is not sufficient to take the same BCs for both operators. We show that, given certain relations between the parameters of the extensions, it is possible to write down the most general domain where both operators H and Λ are self-adjoint with helicity conservation and also Aharonov-Bohm symmetry (φ→φ+1) preserved, where φ is the magnetic flux in natural units. The continuity of the dynamics is also obtained. Our results imply that neither helicity conservation nor Aharonov-Bohm symmetry by itself solves the problem of choosing the 'physical' BCs for this system. (author)
Sheath formation in low-pressure discharges, the Bohm criterion and the consequences of collisions
International Nuclear Information System (INIS)
The space charge density in low-pressure discharges results from the generation of charged particles, the momentum transfer from these particles to the neutral gas and the electric field. A simplified model is used to treat this process analytically and numerically across the whole plasma. The effect of the electric field alone can cause the formation of the space charge sheath if the ion drift velocity υi to the wall exceeds the modified Bohm velocity υC = υB × (ni/ne)1/2, where υB is the Bohm velocity and ni and ne are the number densities of the ions and the electrons, respectively. However, a domain with υi ⩾ υC can occur only if the effect of collisions is weak. This domain is very narrow and does not come up to the wall. Limits of the electric field strength determining the sheath formation are given. It is shown that the electric field strength cannot be set equal to zero at υi = υB or υC under collisional conditions. The sheath extends from the region near the wall towards the centre and a result of that is to lower υi with respect to υB as the collisionality rises. These results are used to take into consideration various sheath criteria. The Bohm criterion takes into account the effect of the electric field only and reveals a well-defined sheath edge at υi = υB. This criterion remains a useful approximation of the sheath edge in almost collisionless plasmas as well. Under collisional conditions the definition of the sheath edge becomes more difficult and a little arbitrary. This paper takes into account new sheath criteria modified for the case of finite collisionality. The divergence between the densities of the ions and the electrons, the gradients of the space charge density and of the generalized Bohm speed υC are studied as functions of υi or the distance from the wall. These criteria are compared with the collisionally modified Bohm criteria proposed by Godyak (1982 Phys. Lett. A 89 80), Valentini (1996 Phys. Plasmas 3
Kondo, Kenji
2016-01-01
Many researchers have reported on spin filters using linear Rashba spin-orbit interactions (SOI). However, spin filters using square and cubic Rashba SOIs have not yet been reported. We consider that this is because the Aharonov-Casher (AC) phases acquired under square and cubic Rashba SOIs are ambiguous. In this study, we try to derive the AC phases acquired under square and cubic Rashba SOIs from the viewpoint of non-Abelian SU(2) gauge theory. These AC phases can be derived successfully from the non-Abelian SU(2) gauge theory without the completing square methods. Using the results, we investigate the spin filtering in a double quantum dot (QD) Aharonov-Bohm (AB) ring under linear, square, and cubic Rashba SOIs. This AB ring consists of elongated QDs and quasi-one-dimensional quantum nanowires under an external magnetic field. The spin transport is investigated from the left nanowire to the right nanowire in the above structure within the tight-binding approximation. In particular, we focus on the difference of spin filtering among linear, square, and cubic Rashba SOIs. The calculation is performed for the spin polarization by changing the penetrating magnetic flux for the AB ring subject to linear, square, and cubic Rashba SOIs. It is found that perfect spin filtering is achieved for all of the Rashba SOIs. This result indicates that this AB ring under general Rashba SOIs can be a promising device for spin current generation. Moreover, the AB rings under general Rashba SOIs behave in totally different ways in response to penetrating magnetic flux, which is attributed to linear, square, and cubic behaviors in the in-plane momentum. This result enables us to make a clear distinction between linear, square, and cubic Rashba SOIs according to the peak position of the perfect spin filtering.
Aharonov-Bohm effect in curved space and cosmic strings
International Nuclear Information System (INIS)
The paper deals with the development of the theory of nonrelativistic particle scattering in the cosmic string field, which is considered as a registration of magnetic and gravitation strings. The effects, which are caused by the finite nature of the transverse parameters of the strings, are taken into account making sufficiently general assumptions about the distribution of the magnetic field and space curvature inside the string. It is shown that in a certain region of angles the differential scattering section significantly depends on the string magnetic flux value at all absolute values of the bombarding particle wind vector. 34 refs
International Nuclear Information System (INIS)
We discuss holonomic quantum computation based on the scalar Aharonov–Bohm effect for a neutral particle. We show that the interaction between the magnetic dipole moment and external fields yields a non-abelian quantum phase allowing us to make any arbitrary rotation on a one-qubit. Moreover, we show that the interaction between the magnetic dipole moment and a magnetic field in the presence of a topological defect yields an analogue effect of the scalar Aharonov–Bohm effect for a neutral particle, and a new way of building one-qubit quantum gates. - Highlights: ► Holonomic quantum computation for neutral particles. ► Implementation of one-qubit quantum gates based on the Anandan quantum phase. ► Implementation of one-qubit quantum gates based on the scalar Aharonov–Bohm effect.
International Nuclear Information System (INIS)
Using nonequilibrium Green's function techniques, we investigate Andreev reflection and Aharonov-Bohm oscillations through a parallel-coupled double quantum dot connected with a ferromagnetic lead and a superconductor lead. The possibility of controlling Andreev reflection and Aharonov-Bohm oscillations of the system is explored by tuning the interdot coupling, the gate voltage, the magnetic flux, and the intradot spin-flip scattering. When the spin-flip scattering increases, Fano resonant peaks resulting from the asymmetrical levels of the two quantum dots begin to split, and Aharonov-Bohm oscillations are suppressed. Due to the interdot coupling, one strongly and one weakly coupled state of the system can be formed. The magnetic flux can exchange the function of the two states, which leads to a swap effect.
International Nuclear Information System (INIS)
We study the persistent currents induced by both the Aharonov-Bohm and Aharonov-Casher effects in a one-dimensional mesoscopic ring coupled to a sidebranch quantum dot at Kondo resonance. For privileged values of the Aharonov-Bohm-Casher fluxes, the problem can be mapped onto an integrable model, exactly solvable by a Bethe ansatz. In the case of a pure magnetic Aharonov-Bohm flux, we find that the presence of the quantum dot has no effect on the persistent current. In contrast, the Kondo resonance interferes with the spin-dependent Aharonov-Casher effect to induce a current which, in the strong-coupling limit, is independent of the number of electrons in the ring
Scattering of spin 1/2 particles by the 2+1 dimensional noncommutative Aharonov-Bohm potential
International Nuclear Information System (INIS)
In this work we study modifications in the Aharonov-Bohm effect for relativistic spin 1/2 particles due to the noncommutativity of spacetime in 2+1 dimensions. The noncommutativity gives rise to a correction to the Aharonov-Bohm potential which is highly singular at the origin, producing divergences in a perturbative expansion around the usual solution of the free Dirac equation. This problem is surmounted by using a perturbative expansion around the exact solution of the commutative Aharonov-Bohm problem. We calculate, in this setting, the scattering amplitude and the corrections to the differential and total cross sections for a spin 1/2 particle, in the small-flux limit
A uniﬁed view on Aharanov–Bohm like phases and some applications
Indian Academy of Sciences (India)
C S Unnikrishnan
2001-02-01
The analysis of the Aharanov–Bohm phase and other similar physical effects in this paper is motivated by the philosophy that all physical changes, including phase changes, should originate in one of the local physical interactions even if they are described elegantly and concisely as topological or geometric changes. The topological or geometric nature comes about either due to an additional physical principle or due to certain special spatial or temporal property of the ﬁelds from the source. Similar remarks apply to rotation or precession of polarization and spin vectors. As a primary example I describe the Aharanov–Bohm phase as arising from the Coulomb interaction of a charge in the electrostatic potential created by other charges. The topological nature comes about because the interaction energy has zero gradient throughout space, except in a compact region enclosed by the quantum paths. This analysis brings out the unifying aspects of the scalar and the vector A–B effects, and the Aharanov–Casher phase. Then I discuss two other related problems with descriptions in the geometrical and the interaction pictures; I discuss how quantum complementarity is realized without the Heisenberg back action on momentum in certain atom interferometry experiments. In the second example, I show that the Thomas precession of the spin results from the local torque in the accelero-magnetic ﬁeld, a ﬁeld predicted in analogy with the gravitomagnetic ﬁeld. I end the discussion with some remarks on the classical nature of fringe shifts in Aharanov–Bohm like phenomena in electromagnetism and gravitation.
Grochol, M.; Grosse, F.; Zimmermann, R.
2005-01-01
The optical exciton Aharonov-Bohm effect, i. e. an oscillatory component in the energy of optically active (bright) states, is investigated in nanorings. It is shown that a small effective electron mass, strong confinement of the electron, and high barrier for the hole, achieved e. g. by an InAs nanoring embedded in an AlGaSb quantum well, are favorable for observing the optical exciton Aharonov-Bohm effect. The second derivative of the exciton energy with respect to the magnetic field is uti...
Barseghyan, M. G.; Manaselyan, A. Kh.; Laroze, D.; Kirakosyan, A. A.
2016-07-01
In this work we study the electronic states in quantum dot-ring complex nanostructures with an on-center hydrogenic impurity. The influence of the impurity on Aharonov-Bohm energy spectra oscillations and intraband optical absorption is investigated. It is shown that in the presence of a hydrogenic donor impurity the Aharonov-Bohm oscillations in quantum dot-ring structures become highly tunable. Furthermore, the presence of the impurity drastically changes the intraband absorption spectra due to the strong controllability of the electron localization type.
Measurement in the de Broglie-Bohm interpretation: Double-slit, Stern-Gerlach and EPR-B
Michel Gondran; Alexandre Gondran
2014-01-01
We propose a pedagogical presentation of measurement in the de Broglie-Bohm interpretation. In this heterodox interpretation, the position of a quantum particle exists and is piloted by the phase of the wave function. We show how this position explains determinism and realism in the three most important experiments of quantum measurement: double-slit, Stern-Gerlach and EPR-B. First, we demonstrate the conditions in which the de Broglie-Bohm interpretation can be assumed to be valid through co...
2D Pauli Equation with Hulthén Potential in the Presence of Aharonov—Bohm Effect
International Nuclear Information System (INIS)
The 2D Pauli equation with Hulthén potential for spin-1/2 particle in the presence of Aharonov—Bohm (AB) field is solved analytically, on the assumption that an effective approximation is used for the centrifugal term. Singular and regular solutions of the problem are obtained. It is shown that the AB field lifts the degeneracy of the energy levels. The range of the flux parameter for which singular solutions are allowed is modified compared to the pure AB case. When the screening parameter vanishes, it is shown that the obtained energy spectrum becomes the same as that of the Aharonov—Bohm Coulomb problem. (general)
2D Pauli Equation with Hulthén Potential in the Presence of Aharonov—Bohm Effect
Ferkous, N.; Bounames, A.
2013-06-01
The 2D Pauli equation with Hulthén potential for spin-1/2 particle in the presence of Aharonov—Bohm (AB) field is solved analytically, on the assumption that an effective approximation is used for the centrifugal term. Singular and regular solutions of the problem are obtained. It is shown that the AB field lifts the degeneracy of the energy levels. The range of the flux parameter for which singular solutions are allowed is modified compared to the pure AB case. When the screening parameter vanishes, it is shown that the obtained energy spectrum becomes the same as that of the Aharonov—Bohm Coulomb problem.
Zhang, G.; Li, X.Q.(Nankai University, Tianjin, 300071, People's Republic of China); Zhang, X. Z.; Song, Z.
2014-01-01
We study the effect of PT-symmetric imaginary potentials embedded in the two arms of an Aharonov-Bohm interferometer on the transmission phase by finding an exact solution for a concrete tight-binding system. It is observed that the spectral singularity always occurs at k=${\\pm}${\\pi}/2 for a wide range of fluxes and imaginary potentials. Critical behavior associated with the physics of the spectral singularity is also investigated. It is demonstrated that the quasi-spectral singularity corre...
Interrelations Between the Neutron's Magnetic Interactions and the Magnetic Aharonov-Bohm Effect
Comay, E
1999-01-01
It is proved that the phase shift of a polarized neutron interacting with a spatially uniform time-dependent magnetic field, demonstrates the same physical principles as the magnetic Aharonov-Bohm effect. The crucial role of inert objects is explained, thereby proving the quantum mechanical nature of the effect. It is also proved that the nonsimply connectedness of the field-free region is not a profound property of the system and that it cannot be regarded as a sufficient condition for a nonzero phase shift.
Absence of the Electric Aharonov-Bohm Effect due to Induced Charges
Rui-Feng Wang
2015-01-01
This paper states that the induced charge should not be neglected in the electric Aharonov-Bohm (A-B) effect. If the induced charge is taken into account, the interference pattern of the moving charge will not change with the potential difference between the two metal tubes. It means that the scalar potential itself can not affect the phase of the moving charge, and the true factor affecting the phase of the moving charge is the energy of the system including the moving charge and the induced...
Non-Abelian Aharonov-Bohm effect with the time-dependent gauge fields
Hosseini Mansoori, Seyed Ali; Mirza, Behrouz
2016-04-01
We investigate the non-Abelian Aharonov-Bohm (AB) effect for time-dependent gauge fields. We prove that the non-Abelian AB phase shift related to time-dependent gauge fields, in which the electric and magnetic fields are written in the adjoint representation of SU (N) generators, vanishes up to the first order expansion of the phase factor. Therefore, the flux quantization in a superconductor ring does not appear in the time-dependent Abelian or non-Abelian AB effect.
Absence of the Electric Aharonov-Bohm Effect due to Induced Charges
Wang, Rui-Feng
2015-09-01
This paper states that the induced charge should not be neglected in the electric Aharonov-Bohm (A-B) effect. If the induced charge is taken into account, the interference pattern of the moving charge will not change with the potential difference between the two metal tubes. It means that the scalar potential itself can not affect the phase of the moving charge, and the true factor affecting the phase of the moving charge is the energy of the system including the moving charge and the induced charge.
Kondo effect in transport through Aharonov-Bohm and Aharonov-Casher interferometers
Lobos, A. M.; Aligia, A. A.
2009-01-01
We derive the extension of the Hubbard model to include Rashba spin-orbit coupling that correctly describes Aharonov-Bohm and Aharonov-Casher phases in a ring under applied magnetic and electric fields. When the ring is connected to conducting leads, we develop a formalism that is able to describe both, Kondo and interference effects. We find that in the Kondo regime, the spin-orbit coupling reduces strongly the conductance from the unitary limit. This effect in combination with the magnetic ...
Asymptotics of the many-whirls representation for Aharonov-Bohm scattering
International Nuclear Information System (INIS)
The previously derived decomposition of the Aharonov-Bohm (AB) wavefunction, into 'whirling waves' that wind different numbers of times round the flux line, is studied in detail. Asymptotic approximations are derived, describing many windings, far from the flux, and near the forward direction where the incident and scattered waves cannot be separated. The many-whirls representation gives insight into elementary explanations of the AB in terms of interference between waves passing on either side of the flux; three whirling waves suffice to give a very accurate description of the AB wave.
Force-free gravitational redshift: proposed gravitational Aharonov-Bohm experiment.
Hohensee, Michael A; Estey, Brian; Hamilton, Paul; Zeilinger, Anton; Müller, Holger
2012-06-01
We propose a feasible laboratory interferometry experiment with matter waves in a gravitational potential caused by a pair of artificial field-generating masses. It will demonstrate that the presence of these masses (and, for moving atoms, time dilation) induces a phase shift, even if it does not cause any classical force. The phase shift is identical to that produced by the gravitational redshift (or time dilation) of clocks ticking at the atom's Compton frequency. In analogy to the Aharonov-Bohm effect in electromagnetism, the quantum mechanical phase is a function of the gravitational potential and not the classical forces. PMID:23003927
Non-Abelian Aharonov-Bohm effect with the time-dependent gauge fields
Mansoori, Seyed Ali Hosseini
2016-01-01
We investigate the non-Abelian Aharonov-Bohm (AB) effect for time-dependent gauge fields. We prove that the non-Abelian AB phase shift related to time-dependent gauge fields, in which the electric and magnetic fields are written in the adjoint representation of $SU(N)$ generators, vanishes up to the first order expansion of the phase factor. Therefore, the flux quantization in a superconductor ring does not appear in the time-dependent Abelian or non-Abelian AB effect.
Aharonov–Bohm oscillation of Raman scattering in a quantum ring
International Nuclear Information System (INIS)
An electron Raman scattering process in a semiconductor quantum ring with a repulsive scattering center is investigated in the presence of an external magnetic field. The differential cross section is calculated as a function of the diffusion photon energy. The scattering spectra are discussed for the different magnetic field strengths and ring radii. The calculated results show that the electron Raman scattering of quantum rings is strongly affected by the external magnetic field, the ring radius and the impurity. Also we find that the resonant peak of the differential cross section of electron Raman scattering shows the optical Aharonov–Bohm oscillation upon changing the magnetic field and the ring radius.
Kondo effect in transport through Aharonov-Bohm and Aharonov-Casher interferometers
International Nuclear Information System (INIS)
We derive the extension of the Hubbard model to include Rashba spin-orbit coupling that correctly describes Aharonov-Bohm and Aharonov-Casher phases in a ring under applied magnetic and electric fields. When the ring is connected to conducting leads, we develop a formalism that is able to describe both, Kondo and interference effects. We find that in the Kondo regime, the spin-orbit coupling reduces strongly the conductance from the unitary limit. This effect in combination with the magnetic flux, can be used to produce spin polarized carriers.
Aharonov-Bohm interferometer based on n -p junctions in graphene nanoribbons
Mreńca-Kolasińska, A.; Heun, S.; Szafran, B.
2016-03-01
We demonstrate that the phenomenon of current confinement along graphene n -p junctions at high magnetic fields can be used to form an Aharonov-Bohm interferometer. The interference system exploits a closed n -p junction that can be induced by a floating gate within the sample, and coupling of the junction currents with the edge currents in the quantum Hall regime. Operation of the device requires current splitting at the edge and the n -p junction contacts which is found for armchair ribbons at low Fermi energy.
Quantum Faraday Effect in Double-Dot Aharonov-Bohm Ring
Kang, Kicheon
2011-01-01
We investigate Faraday's law of induction manifested in the quantum state of Aharonov-Bohm loops. In particular, we propose a flux-switching experiment for a double-dot AB ring to verify the phase shift induced by Faraday's law. We show that the induced {\\em Faraday phase} is geometric and nontopological. Our study demonstrates that the relation between the local phases of a ring at different fluxes is not arbitrary but is instead determined by Faraday's inductive law, which is in strong cont...
Exact equivalence of spin-1/2 Aharonov-Bohm and Aharonov-Casher effects
International Nuclear Information System (INIS)
It is shown that there is an exact equivalence between the Aharonov-Bohm effect for spin-1/2 particles and the Aharonov-Casher effect. The demonstration of this precise relationship between the two is seen furthermore to be independent of whether relativistic or nonrelativistic kinematics are used. The only remaining substantive distinction between the two effects may well be the fact that the scattering cross section for polarized beams has a considerably greater sturcture in the Aharonov-Casher case despite the mathematical equivalence of the scattering amplitudes for the two effects
Aharonov–Bohm oscillation of Raman scattering in a quantum ring
Energy Technology Data Exchange (ETDEWEB)
Xie, Wenfang, E-mail: xiewf@vip.163.com
2014-04-01
An electron Raman scattering process in a semiconductor quantum ring with a repulsive scattering center is investigated in the presence of an external magnetic field. The differential cross section is calculated as a function of the diffusion photon energy. The scattering spectra are discussed for the different magnetic field strengths and ring radii. The calculated results show that the electron Raman scattering of quantum rings is strongly affected by the external magnetic field, the ring radius and the impurity. Also we find that the resonant peak of the differential cross section of electron Raman scattering shows the optical Aharonov–Bohm oscillation upon changing the magnetic field and the ring radius.
Lai, Wenxi; Xing, Yunhui; Ma, Zhongshui
2013-05-22
Phase relaxation of electrons transferring through an electromechanical transistor is studied using the Aharonov-Bohm interferometer. Using the quantum master equation approach, the phase properties of an electron are numerically analyzed based on the interference fringes. The coherence of the electron is partially destroyed by its scattering on excited levels of the local nanomechanical oscillator. The transmission amplitudes with respect to two adjacent mechanical vibrational levels have a phase difference of π. The character of the π phase shift depends on the oscillator frequency only and is robust over a wide range of values of the applied voltage, tunneling length and damping rate of the mechanical oscillator. PMID:23615899
Non-Abelian Aharonov–Bohm effect with the time-dependent gauge fields
Directory of Open Access Journals (Sweden)
Seyed Ali Hosseini Mansoori
2016-04-01
Full Text Available We investigate the non-Abelian Aharonov–Bohm (AB effect for time-dependent gauge fields. We prove that the non-Abelian AB phase shift related to time-dependent gauge fields, in which the electric and magnetic fields are written in the adjoint representation of SU(N generators, vanishes up to the first order expansion of the phase factor. Therefore, the flux quantization in a superconductor ring does not appear in the time-dependent Abelian or non-Abelian AB effect.
Aharonov-Bohm effect for an exciton in a finite width nano-ring
Palmero, F.; Dorignac, J.; Eilbeck, J. C.; Romer, R. A.
2005-01-01
We study the Aharonov-Bohm effect for an exciton on a nano-ring using a 2D attractive fermionic Hubbard model. We extend previous results obtained for a 1D ring in which only azimuthal motion is considered, to a more general case of 2D annular lattices. In general, we show that the existence of the localization effect, increased by the nonlinearity, makes the phenomenon in the 2D system similar to the 1D case. However, the introduction of radial motion introduces extra frequencies, different ...
Coherent control of interacting particles using dynamical and Aharonov-Bohm phases
Creffield, Charles E.; Platero, G.
2010-01-01
A powerful method of manipulating the dynamics of quantum coherent particles is to control the phase of their tunneling. We consider a system of two electrons hopping on a quasi-one- dimensional lattice in the presence of a uniform magnetic field and study the effect of adding a time-periodic driving potential. We show that the dynamical phases produced by the driving can combine with the Aharonov-Bohm phases to give precise control of the localization and dynamics of the particles, even in t...
Aharonov-Bohm and Aharonov-Casher Effects: Connections to Dynamics of Topological Singularities
Ao, P.; Niu, Q.
1998-01-01
We analyze the physical processes involved in the Aharonov-Bohm (A-B) and the Aharonov-Casher (A-C) effects, showing that an incomplete A-B effect knowledge can lead a totally wrong conclusion on the A-C effect. Based on this we demonstrate that the Magnus force, the net force, is the only transverse force on a moving vortex, in analogous to the net charge in A-C effect. This conclusion has been arrived both theoretically and experimentally.
An experimental scheme to verify the dynamics of the Aharonov–Bohm effect
International Nuclear Information System (INIS)
There are two different viewpoints on the Aharonov–Bohm (A–B) effect. One asserts that the A–B effect is due to the existence of the vector potential A. The other asserts that the A–B effect is due to the interaction energy between the magnetic field produced by the moving charges and the magnetic field in the solenoid. The difference of these two viewpoints is analyzed in this paper. To judge which viewpoint is right, this paper suggests a new experimental method. (general)
Gate controlled Aharonov-Bohm-type oscillations from single neutral excitons in quantum rings
Ding, F.; Akopian, N.; Li, B.; Perinetti, U.; Govorov, A.; Peeters, F. M.; Bof Bufon, C. C.; Deneke, C.; Chen, Y. H.; Rastelli, A.; Schmidt, O. G.; Zwiller, V.
2010-08-01
We report on a magnetophotoluminescence study of single self-assembled semiconductor nanorings which are fabricated by molecular-beam epitaxy combined with AsBr3 in situ etching. Oscillations in the neutral exciton radiative recombination energy and in the emission intensity are observed under an applied magnetic field. Further, we control the period of the oscillations with a gate potential that modifies the exciton confinement. We infer from the experimental results, combined with calculations, that the exciton Aharonov-Bohm effect may account for the observed effects.
International Nuclear Information System (INIS)
Phase relaxation of electrons transferring through an electromechanical transistor is studied using the Aharonov–Bohm interferometer. Using the quantum master equation approach, the phase properties of an electron are numerically analyzed based on the interference fringes. The coherence of the electron is partially destroyed by its scattering on excited levels of the local nanomechanical oscillator. The transmission amplitudes with respect to two adjacent mechanical vibrational levels have a phase difference of π. The character of the π phase shift depends on the oscillator frequency only and is robust over a wide range of values of the applied voltage, tunneling length and damping rate of the mechanical oscillator. (paper)
Modified de Broglie-Bohm approach to the Schwarzschild black hole
Institute of Scientific and Technical Information of China (English)
Wang Bo-Bo
2008-01-01
A modified de Broglie-Bohm approach is generalized to the Schwarzschild black hole. By using this method, the quantum potential and the quantum trajectories of the black hole are investigated. And we find that the linear combination of two particular solutions of the black hole wavefunction is not physical although each of them is physical, if we think that the quantum gravity should reduce into its corresponding classical counterpart in which the gravity vanishes. It seems to confirm the argument, given by Alwis and MacIntire, that a possible resolution on the quantum gravity is to give up the superposition principle.
Non-radiating sources, dynamic anapole and Aharonov-Bohm effect
Nemkov, Nikita A; Fedotov, Vassily A
2016-01-01
We show that any non-radiating source can be represented by a combination of identical, spatially localized distributions of electric and toroidal point dipoles. One of the implications is that at every point of an arbitrary non-radiating source there exists a simple universal relation between the electric and toroidal dipole moments. We also present simple means of describing non-radiating sources and discuss a possible scenario for observing the time-dependent version of the Aharonov-Bohm effect in such systems.
Force-free gravitational redshift: a gravitostatic Aharonov-Bohm experiment
Hohensee, Michael A; Hamilton, Paul; Zeilinger, Anton; Mueller, Holger
2011-01-01
We propose a feasible laboratory interferometry experiment with matter waves in a gravitational potential caused by a pair of artificial field-generating masses. It will demonstrate that the presence of these masses (and, for moving atoms, time dilation) induces a phase shift, even if it does not cause any classical force. The phase shift is identical to that produced by the gravitational redshift (or time dilation) of clocks ticking at the atom's Compton frequency. In analogy to the Aharonov-Bohm effect in electromagnetism, the quantum mechanical phase is a function of the gravitational potential and not the classical forces.
Scattering of spin-polarized electron in an Aharonov Bohm potential
Khalilov, V. R.; Ho, Choon-Lin
2008-05-01
The scattering of spin-polarized electrons in an Aharonov-Bohm vector potential is considered. We solve the Pauli equation in 3 + 1 dimensions taking into account explicitly the interaction between the three-dimensional spin magnetic moment of electron and magnetic field. Expressions for the scattering amplitude and the cross section are obtained for spin-polarized electron scattered off a flux tube of small radius. It is also shown that bound electron states cannot occur in this quantum system. The scattering problem for the model of a flux tube of zero radius in the Born approximation is briefly discussed.
Scattering of spin-polarized electron in an Aharonov--Bohm potential
Khalilov, V R
2007-01-01
The scattering of spin-polarized electrons in an Aharonov--Bohm vector potential is considered. We solve the Pauli equation in 3+1 dimensions taking into account explicitly the interaction between the three-dimensional spin magnetic moment of electron and magnetic field. Expressions for the scattering amplitude and the cross section are obtained for spin-polarized electron scattered off a flux tube of small radius. It is also shown that bound electron states cannot occur in this quantum system. The scattering problem for the model of a flux tube of zero radius in the Born approximation is briefly discussed.
Nonlocal Andreev reflection in a three-terminal Aharonov-Bohm interferometer
International Nuclear Information System (INIS)
We theoretically report a nonlocal Andreev reflection in an Aharonov-Bohm interferometer, which is a three-terminal normal metal/superconductor (NS) mesoscopic hybrid system. It is found that this nonlocal Andreev reflection is sensitive to the systematic parameters, such as the bias voltages, the quantum dot levels, and the external magnetic flux. If we set the chemical potential of one normal metal lead equal to zero, the electronic current in the lead results from two competing processes: the quasiparticle transmission and nonlocal Andreev reflection. The appearance of zero electronic current signals unambiguously the existence of this nonlocal Andreev reflection
Kiess, Thomas E.; Shih, Yan-Hua; Sergienko, A. V.; Alley, Carroll O.
1994-01-01
We report a new two-photon polarization correlation experiment for realizing the Einstein-Podolsky-Rosen-Bohm (EPRB) state and for testing Bell-type inequalities. We use the pair of orthogonally-polarized light quanta generated in Type 2 parametric down conversion. Using 1 nm interference filters in front of our detectors, we observe from the output of a 0.5mm beta - BaB2O4 (BBO) crystal the EPRB correlations in coincidence counts, and measure an associated Bell inequality violation of 22 standard deviations. The quantum state of the photon pair is a polarization analog of the spin-1/2 singlet state.
Quantum transport through two series Aharonov-Bohm interferometers with zero total magnetic flux
Institute of Scientific and Technical Information of China (English)
Wang Jian-Ming; Wang Rui; Zhang Yong-Ping; Liang Jiu-Qing
2007-01-01
With the help of nonequilibrium Green's function technique, the electronic transport through series AharonovBohm (AB) interferometers is investigated. We obtain the AB interference pattern of the transition probability characterized by the algebraic sum φ and the difference θ of two magnetic fluxes, and particularly a general rule of AB oscillation period depending on the ratio of integer quantum numbers of the fluxes. A parity effect is observed, showing the asymmetric AB oscillations with respect to the even and odd quantum numbers of the total flux in antiparallel AB interferometers. It is also shown that the AB flux can shift the Fano resonance peaks of the transmission spectrum.
International Nuclear Information System (INIS)
We consider the motion of free relativistic particles in multiply connected spaces. We show that if one of the spatial dimensions has the topology of a circle then the D dimensional spacetime is compactified to D-1 dimensions and the particle mass increases by an amount which is proportional to a quantum phase factor and inversely proportional to the radius of the circle. We also consider the relativistic Aharonov-Bohm effect and we show that the interference pattern is a universal characteristic due only to the topological properties of the experimental situation and not to the intrinsic properties of the particle. The propagators are calculated in both situations. (author)
Aharonov-Bohm oscillations with fractional period in a multichannel Wigner crystal ring
International Nuclear Information System (INIS)
We study the persistent current in a quasi 1D ring with strongly correlated electrons forming a multichannel Wigner crystal (WC). The influence of the Coulomb interaction manifests itself only in the presence of external scatterers that pin the WC. Two regimes of weak and strong pinning are considered. For strong pinning we predict the Aharonov-Bohm oscillations with fractional period. Fractionalization is due to the interchannel coupling in the process of quantum tunneling of the WC. The fractional period depends on the filling of the channels and may serve as an indicator of non-Fermi-liquid behaviour of interacting electrons in quasi 1D rings. (author). 20 refs
Bastin, Ted
2009-07-01
List of participants; Preface; Part I. Introduction: 1. The function of the colloquium - editorial; 2. The conceptual problem of quantum theory from the experimentalist's point of view O. R. Frisch; Part II. Niels Bohr and Complementarity: The Place of the Classical Language: 3. The Copenhagen interpretation C. F. von Weizsäcker; 4. On Bohr's views concerning the quantum theory D. Bohm; Part III. The Measurement Problem: 5. Quantal observation in statistical interpretation H. J. Groenewold; 6. Macroscopic physics, quantum mechanics and quantum theory of measurement G. M. Prosperi; 7. Comment on the Daneri-Loinger-Prosperi quantum theory of measurement Jeffrey Bub; 8. The phenomenology of observation and explanation in quantum theory J. H. M. Whiteman; 9. Measurement theory and complex systems M. A. Garstens; Part IV. New Directions within Quantum Theory: What does the Quantum Theoretical Formalism Really Tell Us?: 10. On the role of hidden variables in the fundamental structure of physics D. Bohm; 11. Beyond what? Discussion: space-time order within existing quantum theory C. W. Kilmister; 12. Definability and measurability in quantum theory Yakir Aharonov and Aage Petersen; 13. The bootstrap idea and the foundations of quantum theory Geoffrey F. Chew; Part V. A Fresh Start?: 14. Angular momentum: an approach to combinatorial space-time Roger Penrose; 15. A note on discreteness, phase space and cohomology theory B. J. Hiley; 16. Cohomology of observations R. H. Atkin; 17. The origin of half-integral spin in a discrete physical space Ted Bastin; Part VI. Philosophical Papers: 18. The unity of physics C. F. von Weizsäcker; 19. A philosophical obstacle to the rise of new theories in microphysics Mario Bunge; 20. The incompleteness of quantum mechanics or the emperor's missing clothes H. R. Post; 21. How does a particle get from A to B?; Ted Bastin; 22. Informational generalization of entropy in physics Jerome Rothstein; 23. Can life explain quantum mechanics? H. H
Spin-Mediated Consciousness Theory
Hu, Huping; Wu, Maoxin
2004-01-01
A novel theory of consciousness is proposed in this paper. We postulate that consciousness is intrinsically connected to quantum spin since the latter is the origin of quantum effects in both Bohm and Hestenes quantum formulism and a fundamental quantum process associated with the structure of space-time. That is, spin is the “mind-pixel.” The unity of mind is achieved by entanglement of the mind-pixels. Applying these ideas to the particular structures and dynamics of the brain, we theorize ...
The exact form of the Bohm criterion for a collisional plasma
Tsankov, Tsanko Vaskov
2016-01-01
A long-standing debate in the literature about the kinetic form of the Bohm criterion is resolved for plasmas with single positive ion species when transport is dominated by charge exchange collisions. The solution of the Boltzmann equation for the ions gives the exact form free of any divergence and contains an additional term that is not included in the classical result. This term includes collisional and geometric effects and leads to a noticeable correction. Further, the question is addressed whether the space charge argument at the bottom of the Bohm criterion can actually lead to a meaningful definition of the transition point between bulk and sheath. The analysis is supported by a numerical model and experiments, showing excellent agreement throughout. As a novelty in diagnostics, the theoretical results allow from the ion velocity distribution function (IVDF), measured at the wall, a reconstruction of the IVDF and the electric field at any point in the plasma. This property is used to reconstruct non-...
Enhanced spin figure of merit in an Aharonov-Bohm ring with a double quantum dot
Energy Technology Data Exchange (ETDEWEB)
Zhou, Xingfei; Qi, Fenghua; Jin, Guojun, E-mail: gjin@nju.edu.cn [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China)
2014-04-21
We theoretically investigate the thermoelectric effects in an Aharonov-Bohm ring with a serially coupled double quantum dot embedded in one arm. An external magnetic field is perpendicularly applied to the two dots. Using the nonequilibrium Green's function method in the linear-response regime, we calculate the charge and spin figures of merit. When the energy levels of the two quantum dots are equal and the system is connected to two normal leads, a large spin figure of merit (Z{sub s}T ≈ 4.5) accompanying with a small charge figure of merit (Z{sub c}T ≈ 0) can be generated due to the remarkable bipolar effect. Further, when the system is connected to two ferromagnetic leads, the spin figure of merit can reach even a higher value about 9. Afterwards, we find that Z{sub s}T is enhanced while Z{sub c}T is reduced in the coaction of the Aharonov-Bohm flux and Rashba spin-orbit coupling. It is argued that the bipolar effect is positive (negative) to spin (charge) figure of merit in the presence of level detuning of the two quantum dots and intradot Coulomb interactions, respectively. Also, we propose a possible experiment to verify our results.
Aharonov-Bohm oscillations in a quasi-ballistic three-dimensional topological insulator nanowire.
Cho, Sungjae; Dellabetta, Brian; Zhong, Ruidan; Schneeloch, John; Liu, Tiansheng; Gu, Genda; Gilbert, Matthew J; Mason, Nadya
2015-01-01
Aharonov-Bohm oscillations effectively demonstrate coherent, ballistic transport in mesoscopic rings and tubes. In three-dimensional topological insulator nanowires, they can be used to not only characterize surface states but also to test predictions of unique topological behaviour. Here we report measurements of Aharonov-Bohm oscillations in (Bi1.33Sb0.67)Se3 that demonstrate salient features of topological nanowires. By fabricating quasi-ballistic three-dimensional topological insulator nanowire devices that are gate-tunable through the Dirac point, we are able to observe alternations of conductance maxima and minima with gate voltage. Near the Dirac point, we observe conductance minima for zero magnetic flux through the nanowire and corresponding maxima (having magnitudes of almost a conductance quantum) at magnetic flux equal to half a flux quantum; this is consistent with the presence of a low-energy topological mode. The observation of this mode is a necessary step towards utilizing topological properties at the nanoscale in post-CMOS applications. PMID:26158768
Enhanced spin figure of merit in an Aharonov-Bohm ring with a double quantum dot
International Nuclear Information System (INIS)
We theoretically investigate the thermoelectric effects in an Aharonov-Bohm ring with a serially coupled double quantum dot embedded in one arm. An external magnetic field is perpendicularly applied to the two dots. Using the nonequilibrium Green's function method in the linear-response regime, we calculate the charge and spin figures of merit. When the energy levels of the two quantum dots are equal and the system is connected to two normal leads, a large spin figure of merit (ZsT ≈ 4.5) accompanying with a small charge figure of merit (ZcT ≈ 0) can be generated due to the remarkable bipolar effect. Further, when the system is connected to two ferromagnetic leads, the spin figure of merit can reach even a higher value about 9. Afterwards, we find that ZsT is enhanced while ZcT is reduced in the coaction of the Aharonov-Bohm flux and Rashba spin-orbit coupling. It is argued that the bipolar effect is positive (negative) to spin (charge) figure of merit in the presence of level detuning of the two quantum dots and intradot Coulomb interactions, respectively. Also, we propose a possible experiment to verify our results
'Aharonov-Bohm antiferromagnetism' and compensation points in the lattice of quantum rings
International Nuclear Information System (INIS)
We investigate the magnetic properties of the lattice of non-interacting quantum rings using the 2D rotator model. The exact analytic expressions for the free energy as well as for the magnetization and magnetic susceptibility are found and analyzed. It is shown that such a system can be considered as a system with antiferromagnetic-like properties. We have shown also that all observable quantities in this case (free energy, entropy, magnetization) are periodic functions of the magnetic flux through the ring's area (as well known, such a behavior is typical for the Aharonov-Bohm effect). For the lattice of quantum rings with two different geometric parameters we investigate the ordinary compensation points ('temperature compensation points', i.e. points at which the magnetization vanishes at fixed values of the magnetic field strength). It is shown that the positions of compensation points in the temperature scale are very sensitive to small changes in the magnetic field strength. - Highlights: → The lattice of quantum rings as a system with antiferromagnetic-like properties. → In considered system the 'temperature compensation points' take place. → The 'temperature compensation points' positions depend on the Aharonov-Bohm flux.
Excitonic Aharonov-Bohm effect: Unstrained versus strained type-I semiconductor nanorings
Tadić, M.; Čukarić, N.; Arsoski, V.; Peeters, F. M.
2011-09-01
We study how mechanical strain affects the magnetic field dependence of the exciton states in type-I semiconductor nanorings. Strain spatially separates the electron and hole in (In,Ga)As/GaAs nanorings which is beneficial for the occurrence of the excitonic Aharonov-Bohm (AB) effect. In narrow strained (In,Ga)As/GaAs nanorings the AB oscillations in the exciton ground-state energy are due to anticrossings with the first excited state. No such AB oscillations are found in unstrained GaAs/(Al,Ga)As nanorings irrespective of the ring width. Our results are obtained within an exact numerical diagonalization scheme and are shown to be accurately described by a two-level model with off-diagonal coupling t. The later transfer integral expresses the Coulomb coupling between states of electron-hole pairs. We also found that the oscillator strength for exciton recombination in (In,Ga)As/GaAs nanorings exhibits AB oscillations, which are superimposed on a linear increase with magnetic field. Our results agree qualitatively with recent experiments on the excitonic Aharonov-Bohm effect in type-I (In,Ga)As/GaAs nanorings.
Spin–spin correlations of entangled qubit pairs in the Bohm interpretation of quantum mechanics
International Nuclear Information System (INIS)
A general entangled qubit pair is analyzed in the de Broglie–Bohm formalism corresponding to two spin-1/2 quantum rotors. Several spin–spin correlators of Bohm’s hidden variables are analyzed numerically and a detailed comparison with results obtained by standard quantum mechanics is outlined. In addition to various expectation values, the Bohm interpretation also allows a study of the corresponding probability distributions, which enables a novel understanding of entangled qubit dynamics. In particular, it is shown how the angular momenta of two qubits in this formalism can be viewed geometrically and characterized by their relative angles. For perfectly entangled pairs, for example, a compelling picture is given, where the qubits exhibit a unison precession making a constant angle between their angular momenta. It is also demonstrated that the properties of standard quantum mechanical spin-spin correlators responsible for the violation of Bell’s inequalities are identical to their counterparts emerging from the probability distributions obtained by the Bohmian approach. (paper)
Spin filtering in a Rashba–Dresselhaus–Aharonov–Bohm double-dot interferometer
International Nuclear Information System (INIS)
We study the spin-dependent transport of spin-1/2 electrons through an interferometer made of two elongated quantum dots or quantum nanowires, which are subject to both an Aharonov–Bohm flux and (Rashba and Dresselhaus) spin–orbit interactions. Similar to the diamond interferometer proposed in our previous papers (Aharony et al 2011 Phys. Rev. B 84 035323; Matityahu et al 2013 Phys. Rev. B 87 205438), we show that the double-dot interferometer can serve as a perfect spin filter due to a spin interference effect. By appropriately tuning the external electric and magnetic fields which determine the Aharonov–Casher and Aharonov–Bohm phases, and with some relations between the various hopping amplitudes and site energies, the interferometer blocks electrons with a specific spin polarization, independent of their energy. The blocked polarization and the polarization of the outgoing electrons is controlled solely by the external electric and magnetic fields and do not depend on the energy of the electrons. Furthermore, the spin filtering conditions become simpler in the linear-response regime, in which the electrons have a fixed energy. Unlike the diamond interferometer, spin filtering in the double-dot interferometer does not require high symmetry between the hopping amplitudes and site energies of the two branches of the interferometer and thus may be more appealing from an experimental point of view. (paper)
Fermions in scalar Coulomb and Aharonov-Bohm potentials in 2+1 dimensions
Energy Technology Data Exchange (ETDEWEB)
Khalilov, V R; Lee, K E, E-mail: khalilov@phys.msu.ru [Faculty of Physics, Moscow State University, 119991 Moscow (Russian Federation)
2011-05-20
The quantum-mechanical problem of constructing the self-adjoint Hamiltonians is physically rigorously solved for a Dirac Hamiltonian with a Coulomb scalar potential and an Aharonov-Bohm potential in 2+1 dimensions by taking into account a fermion spin. It is found that the Dirac Hamiltonian on this background requires the additional specification of a one-parameter self-adjoint extension, which can be given in terms of the physically acceptable boundary conditions. We derive equations that determine the spectra of the self-adjoint radial Dirac Hamiltonians for various parameter values. We discuss the role of a particle spin as the physical reason of the existence of bound fermion states in a pure Aharonov-Bohm potential and show that the particle and antiparticle states with zero energy exist only owing to the interaction of the fermion spin magnetic moment with the magnetic field. The energy levels of particles and antiparticles are intersected what may signal on the instability of a quantum system.
Energy Technology Data Exchange (ETDEWEB)
Andrade, F.M., E-mail: fmandrade@uepg.br [Departamento de Matemática e Estatística, Universidade Estadual de Ponta Grossa, 84030-900 Ponta Grossa-PR (Brazil); Silva, E.O., E-mail: edilbertoo@gmail.com [Departamento de Física, Universidade Federal do Maranhão, Campus Universitário do Bacanga, 65085-580 São Luís-MA (Brazil); Pereira, M., E-mail: marciano@uepg.br [Departamento de Matemática e Estatística, Universidade Estadual de Ponta Grossa, 84030-900 Ponta Grossa-PR (Brazil)
2013-12-15
In this work the bound state and scattering problems for a spin- 1/2 particle undergone to an Aharonov–Bohm potential in a conical space in the nonrelativistic limit are considered. The presence of a δ-function singularity, which comes from the Zeeman spin interaction with the magnetic flux tube, is addressed by the self-adjoint extension method. One of the advantages of the present approach is the determination of the self-adjoint extension parameter in terms of physics of the problem. Expressions for the energy bound states, phase-shift and S matrix are determined in terms of the self-adjoint extension parameter, which is explicitly determined in terms of the parameters of the problem. The relation between the bound state and zero modes and the failure of helicity conservation in the scattering problem and its relation with the gyromagnetic ratio g are discussed. Also, as an application, we consider the spin- 1/2 Aharonov–Bohm problem in conical space plus a two-dimensional isotropic harmonic oscillator. -- Highlights: •Planar dynamics of a spin- 1/2 neutral particle. •Bound state for Aharonov–Bohm systems. •Aharonov–Bohm scattering. •Helicity nonconservation. •Determination of the self-adjoint extension parameter.
Aharonov-Bohm and Aharonov-Casher tunneling effects and edge states in double-barrier structures
International Nuclear Information System (INIS)
The simultaneous occurrence of Aharonov-Bohm (AB) and Aharonov-Casher (AC) effects due to edge states in double-barrier two-dimensional wires formed by an electrostatic confinement potential, in the quantum Hall effect regime, is discussed. The AC effect is manifested via a shift of the AB conductance oscillations, and a method for measurement of the effect is proposed
International Nuclear Information System (INIS)
In this work the bound state and scattering problems for a spin- 1/2 particle undergone to an Aharonov–Bohm potential in a conical space in the nonrelativistic limit are considered. The presence of a δ-function singularity, which comes from the Zeeman spin interaction with the magnetic flux tube, is addressed by the self-adjoint extension method. One of the advantages of the present approach is the determination of the self-adjoint extension parameter in terms of physics of the problem. Expressions for the energy bound states, phase-shift and S matrix are determined in terms of the self-adjoint extension parameter, which is explicitly determined in terms of the parameters of the problem. The relation between the bound state and zero modes and the failure of helicity conservation in the scattering problem and its relation with the gyromagnetic ratio g are discussed. Also, as an application, we consider the spin- 1/2 Aharonov–Bohm problem in conical space plus a two-dimensional isotropic harmonic oscillator. -- Highlights: •Planar dynamics of a spin- 1/2 neutral particle. •Bound state for Aharonov–Bohm systems. •Aharonov–Bohm scattering. •Helicity nonconservation. •Determination of the self-adjoint extension parameter
International Nuclear Information System (INIS)
Vector solutions of the Laplace equation are obtained. Their properties and possible applications are discussed. Conditions are found for the nonradiation of charge and current densities periodically changing with time. Electromagnetic properties of the solenoid with non-zero helicity and the influence of the latter on the Aharonov-Bohm scattering are stidied. 20 refs
Freire, O
2005-01-01
This article focuses on the reception among physicists of Bohm's 1952 papers on the causal interpretation of quantum mechanics, which were poorly received at the time. I describe his Brazilian exile and analyze the culture of physics surrounding the foundations of quantum mechanics. I take into account the strength of the Copenhagen interpretation among physicists, the way in which issues concerning the foundations of quantum mechanics were present in the training of physicists, the low status of these issues on research agendas, and the kind of results Bohm and collaborators were able to achieve. I also compare the reception of Bohm's ideas with that of Hugh Everett's interpretation and argue that the obstacles growing from the cultural context of physics at that time had a more significant influence in the reception of Bohm's ideas than did the vicissitudes related to the McCarthyist climate.
Transmission through a quantum dot molecule embedded in an Aharonov-Bohm interferometer.
Lovey, Daniel A; Gomez, Sergio S; Romero, Rodolfo H
2011-10-26
We study theoretically the transmission through a quantum dot molecule embedded in the arms of an Aharonov-Bohm four quantum dot ring threaded by a magnetic flux. The tunable molecular coupling provides a transmission pathway between the interferometer arms in addition to those along the arms. From a decomposition of the transmission in terms of contributions from paths, we show that antiresonances in the transmission arise from the interference of the self-energy along different paths and that application of a magnetic flux can produce the suppression of such antiresonances. The occurrence of a period of twice the quantum of flux arises at the opening of the transmission pathway through the dot molecule. Two different connections of the device to the leads are considered and their spectra of conductance are compared as a function of the tunable parameters of the model. PMID:21970845
Wave-packet rectification in nonlinear electronic systems: A tunable Aharonov-Bohm diode
Li, Yunyun; Marchesoni, Fabio; Li, Baowen
2014-01-01
Rectification of electron wave-packets propagating along a quasi-one dimensional chain is commonly achieved via the simultaneous action of nonlinearity and longitudinal asymmetry, both confined to a limited portion of the chain termed wave diode. However, it is conceivable that, in the presence of an external magnetic field, spatial asymmetry perpendicular to the direction of propagation suffices to ensure rectification. This is the case of a nonlinear ring-shaped lattice with different upper and lower halves (diode), which is attached to two elastic chains (leads). The resulting device is mirror symmetric with respect to the ring vertical axis, but mirror asymmetric with respect to the chain direction. Wave propagation along the two diode paths can be modeled for simplicity by a discrete Schr\\"odinger equation with cubic nonlinearities. Numerical simulations demonstrate that, thanks to the Aharonov-Bohm effect, such a diode can be operated by tuning the magnetic flux across the ring.
Gaussian Curvature and Global effects : gravitational Aharonov-Bohm effect revisited
Nouri-Zonoz, M
2013-01-01
Using the Gauss-Bonnet formula, integral of the Gaussian curvature over a 2-surface enclosed by a curve in the asymptotically flat region of a static spacetime was found to be a measure of a gravitational analogue of Aharonov-Bohm effect by Ford and Vilenkin in the linearized regime. Employing the 1+3 formulation of spacetime decomposition we study the same effect in the context of full Einstein field equations for stationary spacetimes. Applying our approach to static tube-like and cylindrical distributions of dust not only we recover their result but also obtain an extra term which is interpreted to be representing the classical version of the Colella-Overhauser-Werner effect (the COW experiment).
Topological phases reviewed: The Aharonov Bohm, Aharonov Casher, and He McKellar Wilkens phases
International Nuclear Information System (INIS)
There are three topological phases related to electromagnetic interactions in quantum mechanics: 1. The Aharonov Bohm phase acquired when a charged particle encircles a magnetic field but travels through a field free region. 2. The Aharonov Casher phase acquired when a magnetic dipole encircles electric charges but travels through a charge free region. 3. The He McKellar Wilkens phase acquired when an electric dipole encircles magnetic charges but travels through a charge free region. We review the conditions under which these phases are indeed topological and their experimental realisation. Because the He McKellar Wilkens phase has been recently observed we pay particular attention to how the basic concept of 'an electric dipole encircles magnetic charges' was realised experimentally, and discuss possible future experimental realisations
Aharonov-Bohm oscillations in Dirac semimetal Cd3As2 nanowires
Wang, Li-Xian; Li, Cai-Zhen; Yu, Da-Peng; Liao, Zhi-Min
2016-02-01
Three-dimensional Dirac semimetals, three-dimensional analogues of graphene, are unusual quantum materials with massless Dirac fermions, which can be further converted to Weyl fermions by breaking time reversal or inversion symmetry. Topological surface states with Fermi arcs are predicted on the surface and have been observed by angle-resolved photoemission spectroscopy experiments. Although the exotic transport properties of the bulk Dirac cones have been demonstrated, it is still a challenge to reveal the surface states via transport measurements due to the highly conductive bulk states. Here, we show Aharonov-Bohm oscillations in individual single-crystal Cd3As2 nanowires with low carrier concentration and large surface-to-volume ratio, providing transport evidence of the surface state in three-dimensional Dirac semimetals. Moreover, the quantum transport can be modulated by tuning the Fermi level using a gate voltage, enabling a deeper understanding of the rich physics residing in Dirac semimetals.
Dark states and Aharonov—Bohm oscillations in multi-quantum-dot systems
International Nuclear Information System (INIS)
We study the formation of dark states and the Aharonov—Bohm effect in symmetrically/asymmetrically coupled three- and four-quantum-dot systems. It is found that without a transverse magnetic field, destructive interference can trap an electron in a dark state. However, the introduction of a transverse magnetic field can disrupt the dark state, giving rise to oscillation in current. For symmetrically structured quantum-dot systems, the oscillation has a period of one flux quanta. But for asymmetrically structured dot systems, the period of oscillation is halved. In addition, the dephasing due to charge noise also blocks the formation of dark states, while it does not change the period of oscillation. (general)
Effects of quantum deformation on the spin-1/2 Aharonov–Bohm problem
Energy Technology Data Exchange (ETDEWEB)
Andrade, F.M., E-mail: fmandrade@uepg.br [Departamento de Matemática e Estatística, Universidade Estadual de Ponta Grossa, 84030-900 Ponta Grossa-PR (Brazil); Silva, E.O., E-mail: edilbertoos@pq.cnpq.br [Departamento de Física, Universidade Federal do Maranhão, Campus Universitário do Bacanga, 65085-580 São Luís-MA (Brazil)
2013-02-26
In this Letter we study the Aharonov–Bohm problem for a spin-1/2 particle in the quantum deformed framework generated by the κ-Poincaré–Hopf algebra. We consider the nonrelativistic limit of the κ-deformed Dirac equation and use the spin-dependent term to impose an upper bound on the magnitude of the deformation parameter ε. By using the self-adjoint extension approach, we examine the scattering and bound state scenarios. After obtaining the scattering phase shift and the S-matrix, the bound states energies are obtained by analyzing the pole structure of the latter. Using a recently developed general regularization prescription [Phys. Rev. D. 85 (2012) 041701(R)], the self-adjoint extension parameter is determined in terms of the physics of the problem. For last, we analyze the problem of helicity conservation.
Effects of quantum deformation on the spin-1/2 Aharonov–Bohm problem
International Nuclear Information System (INIS)
In this Letter we study the Aharonov–Bohm problem for a spin-1/2 particle in the quantum deformed framework generated by the κ-Poincaré–Hopf algebra. We consider the nonrelativistic limit of the κ-deformed Dirac equation and use the spin-dependent term to impose an upper bound on the magnitude of the deformation parameter ε. By using the self-adjoint extension approach, we examine the scattering and bound state scenarios. After obtaining the scattering phase shift and the S-matrix, the bound states energies are obtained by analyzing the pole structure of the latter. Using a recently developed general regularization prescription [Phys. Rev. D. 85 (2012) 041701(R)], the self-adjoint extension parameter is determined in terms of the physics of the problem. For last, we analyze the problem of helicity conservation
Thermoelectric effect in an Aharonov-Bohm ring with an embedded quantum dot.
Zheng, Jun; Chi, Feng; Lu, Xiao-Dong; Zhang, Kai-Cheng
2012-01-01
Thermoelectric effect is studied in an Aharonov-Bohm interferometer with an embedded quantum dot (QD) in the Coulomb blockade regime. The electrical conductance, electron thermal conductance, thermopower, and thermoelectric figure-of-merit are calculated by using the Keldysh Green's function method. It is found that the figure-of-merit ZT of the QD ring may be quite high due to the Fano effect originated from the quantum interference effect. Moreover, the thermoelectric efficiency is sensitive to the magnitude of the dot-lead and inter-lead coupling strengthes. The effect of intradot Coulomb repulsion on ZT is significant in the weak-coupling regime, and then large ZT values can be obtained at rather high temperature. PMID:22369454
Aharonov-Bohm effect in the tunnelling of a quantum rotor in a linear Paul trap.
Noguchi, Atsushi; Shikano, Yutaka; Toyoda, Kenji; Urabe, Shinji
2014-01-01
Quantum tunnelling is a common fundamental quantum mechanical phenomenon that originates from the wave-like characteristics of quantum particles. Although the quantum tunnelling effect was first observed 85 years ago, some questions regarding the dynamics of quantum tunnelling remain unresolved. Here we realize a quantum tunnelling system using two-dimensional ionic structures in a linear Paul trap. We demonstrate that the charged particles in this quantum tunnelling system are coupled to the vector potential of a magnetic field throughout the entire process, even during quantum tunnelling, as indicated by the manifestation of the Aharonov-Bohm effect in this system. The tunnelling rate of the structures periodically depends on the strength of the magnetic field, whose period is the same as the magnetic flux quantum φ0 through the rotor [(0.99 ± 0.07) × φ0]. PMID:24820051
Against a proposed alternative explanation of the Aharonov-Bohm effect
International Nuclear Information System (INIS)
The Aharonov-Bohm (AB) effect is understood to demonstrate that the Maxwell fields can act nonlocally in some situations. However it has been suggested from time to time that the AB effect is somehow a consequence of a local classical electromagnetic field phenomenon involving energy that is temporarily stored in the overlap between the external field and the field of which the beam particle is the source. That idea was shown in the past not to work for some models of the source of the external field. Here a more general proof is presented for the magnetic AB effect to show that the overlap energy is always compensated by another contribution to the energy of the magnetic field in such a way that the sum of the two is independent of the external flux. Therefore no such mechanism can underlie the AB effect.
Wave-packet rectification in nonlinear electronic systems: a tunable Aharonov-Bohm diode.
Li, Yunyun; Zhou, Jun; Marchesoni, Fabio; Li, Baowen
2014-01-01
Rectification of electron wave-packets propagating along a quasi-one dimensional chain is commonly achieved via the simultaneous action of nonlinearity and longitudinal asymmetry, both confined to a limited portion of the chain termed wave diode. However, it is conceivable that, in the presence of an external magnetic field, spatial asymmetry perpendicular to the direction of propagation suffices to ensure rectification. This is the case of a nonlinear ring-shaped lattice with different upper and lower halves (diode), which is attached to two elastic chains (leads). The resulting device is mirror symmetric with respect to the ring vertical axis, but mirror asymmetric with respect to the chain direction. Wave propagation along the two diode paths can be modeled for simplicity by a discrete Schrödinger equation with cubic nonlinearities. Numerical simulations demonstrate that, thanks to the Aharonov-Bohm effect, such a diode can be operated by tuning the magnetic flux across the ring. PMID:24691462
Topological phases reviewed: The Aharonov Bohm, Aharonov Casher, and He McKellar Wilkens phases
Energy Technology Data Exchange (ETDEWEB)
McKellar, B. H. J. [ARC Centre of Excellence for Particle Physics at the Terrascale, School of Physics, University of Melbourne (Australia); He, X-G. [Department of Physics, National Taiwan University, Taipei, Taiwan (China); Klein, A. G. [School of Physics, University of Melbourne (Australia)
2014-03-05
There are three topological phases related to electromagnetic interactions in quantum mechanics: 1. The Aharonov Bohm phase acquired when a charged particle encircles a magnetic field but travels through a field free region. 2. The Aharonov Casher phase acquired when a magnetic dipole encircles electric charges but travels through a charge free region. 3. The He McKellar Wilkens phase acquired when an electric dipole encircles magnetic charges but travels through a charge free region. We review the conditions under which these phases are indeed topological and their experimental realisation. Because the He McKellar Wilkens phase has been recently observed we pay particular attention to how the basic concept of 'an electric dipole encircles magnetic charges' was realised experimentally, and discuss possible future experimental realisations.
The Aharonov-Bohm effect and fractional statistics of distinguishable particles
International Nuclear Information System (INIS)
In two-dimensional space, the topological coupling arising between charged particles with attached magnetic fluxes, via the Aharonov-Bohm effect, causes distinguishable particles to effectively acquire quantum statistics: a nontrivial quantum phase is generated when a particle of one species encircles one of a different species. We discuss a number of exact and numerical results concerning distinguishable particles with fractional statistics. Just like for anyons, the spectrum of such particles confined to the lowest Landau level of a strong magnetic field can be found exactly. Then a system of particles in the presence of static magnetic fluxes (equivalent to particles with infinite mass) is considered, and the low-lying states of one particle in the presence of two fluxes and two particles in the presence of one flux are analyzed.
Nguyen, V Hung; Niquet, Y-M; Dollfus, P
2014-05-21
We report on a numerical study of the Aharonov-Bohm (AB) effect and parity selective tunneling in pn junctions based on rectangular graphene rings where the contacts and ring arms are all made of zigzag nanoribbons. We find that when applying a magnetic field to the ring, the AB interference can reverse the parity symmetry of incoming waves and hence can strongly modulate the parity selective transmission through the system. Therefore, the transmission between two states of different parity exhibits the AB oscillations with a π-phase shift, compared to the case of states of the same parity. On this basis, it is shown that interesting effects, such as giant (both positive and negative) magnetoresistance and strong negative differential conductance, can be achieved in this structure. Our study thus presents a new property of the AB interference in graphene nanorings, which could be helpful for further understanding the transport properties of graphene mesoscopic systems. PMID:24785639
International Nuclear Information System (INIS)
Using the Keldysh nonequilibrium Green function and equation-of-motion technique, this paper studies the magnetotransport through an Aharonov–Bohm (AB) ring with parallel double quantum dots coupled to ferromagnetic leads. It calculates the transmission probability in both the equilibrium and the nonequilibrium case, analyses the conductance and the tunnel magnetoresistance for various parameters, and obtains some new results. These results show that this system is provided with an excellent spin filtering property, and that a large tunnelling magnetoresistance and a negative tunnelling magnetoresistance can arise by adjusting relative parameters; these facts indicate that this system is a possible candidate for spin valve transistors, and has important applications in spintronics. (condensed matter: electronic structure, electrical, magnetic, and optical properties)
Mode Dependency of Quantum Decoherence Studied via an Aharonov-Bohm Interferometer
Lo, Tung-Sheng; Lin, Yiping; Wu, Phillip M.; Ling, Dah-Chin; Chi, C. C.; Chen, Jeng-Chung
2016-02-01
We investigate the dependence of decoherence on the mode number M in a multiple-mode Aharonov-Bohm (AB) interferometer. The design of the AB interferometer allows us to precisely determine M by the additivity rule of ballistic conductors; meanwhile, the decoherence rate is simultaneously deduced by the variance of the AB oscillation amplitude. The AB amplitude decreases and fluctuates with depopulating M . Moreover, the normalized amplitude exhibits a maximum at a specific M (˜9 ). Data analysis reveals that the charge-fluctuation-induced dephasing, which depends on the geometry and the charge relaxation resistance of the system, could play an essential role in the decoherence process. Our results suggest that the phase coherence, in principle, can be optimized using a deliberated design and pave one of the ways toward the engineering of quantum coherence.
The manifestly covariant Aharonov-Bohm effect in terms of the 4D fields
Ivezic, Tomislav
2014-01-01
In this paper it is presented a manifestly covariant formulation of the Aharonov-Bohm (AB) phase difference for the magnetic AB effect . This covariant AB phase is written in terms of the Faraday 2-form F and using the decomposition of F in terms of the electric and magnetic fields as four-dimensional (4D) geometric quantities. It is shown that there is a static electric field outside a stationary solenoid with resistive conductor carrying steady current, which causes that the AB phase difference in the magnetic AB effect may be determined by the electric part of the covariant expression, i.e. by the local influence of the 4D electric field and not, as generally accepted,in terms of nonzero vector potential.
Spin Accumulation in a Double Quantum Dot Aharonov–Bohm Interferometer
International Nuclear Information System (INIS)
We investigate the spin accumulation in a double quantum dot Aharonov–Bohm (AB) interferometer in which both the Rashba spin–orbit (RSO) interaction and intradot Coulomb interaction are taken into account. Due to the existence of the RSO interaction, the electron, flowing through different arms of the AB ring, will acquire a spin-dependent phase factor in the tunnel-coupling strengths. This phase factor will induce various interesting interference phenomena. It is found that the electrons of the different spin directions can accumulate in the two dots by properly adjusting the bias and the intradot level with a fixed RSO interaction strength. Moreover, both the magnitude and direction of the spin accumulation in each dot can be conveniently controlled and tuned by the gate voltage acting on the dot or the bias on the lead
Aharonov–Bohm oscillations in Dirac semimetal Cd3As2 nanowires
Wang, Li-Xian; Li, Cai-Zhen; Yu, Da-Peng; Liao, Zhi-Min
2016-01-01
Three-dimensional Dirac semimetals, three-dimensional analogues of graphene, are unusual quantum materials with massless Dirac fermions, which can be further converted to Weyl fermions by breaking time reversal or inversion symmetry. Topological surface states with Fermi arcs are predicted on the surface and have been observed by angle-resolved photoemission spectroscopy experiments. Although the exotic transport properties of the bulk Dirac cones have been demonstrated, it is still a challenge to reveal the surface states via transport measurements due to the highly conductive bulk states. Here, we show Aharonov–Bohm oscillations in individual single-crystal Cd3As2 nanowires with low carrier concentration and large surface-to-volume ratio, providing transport evidence of the surface state in three-dimensional Dirac semimetals. Moreover, the quantum transport can be modulated by tuning the Fermi level using a gate voltage, enabling a deeper understanding of the rich physics residing in Dirac semimetals. PMID:26902716
International Nuclear Information System (INIS)
We report on a numerical study of the Aharonov–Bohm (AB) effect and parity selective tunneling in pn junctions based on rectangular graphene rings where the contacts and ring arms are all made of zigzag nanoribbons. We find that when applying a magnetic field to the ring, the AB interference can reverse the parity symmetry of incoming waves and hence can strongly modulate the parity selective transmission through the system. Therefore, the transmission between two states of different parity exhibits the AB oscillations with a π−phase shift, compared to the case of states of the same parity. On this basis, it is shown that interesting effects, such as giant (both positive and negative) magnetoresistance and strong negative differential conductance, can be achieved in this structure. Our study thus presents a new property of the AB interference in graphene nanorings, which could be helpful for further understanding the transport properties of graphene mesoscopic systems. (paper)
Polarized excitons in nanorings and the optical Aharonov-Bohm effect
Govorov, A. O.; Ulloa, S. E.; Karrai, K.; Warburton, R. J.
2002-08-01
The quantum nature of matter lies in the wave function phases that accumulate while particles move along their trajectories. A prominent example is the Aharonov-Bohm phase, which has been studied in connection with the conductance of nanostructures. However, optical response in solids is determined by neutral excitations, for which no sensitivity to magnetic flux would be expected. We propose a mechanism for the topological phase of a neutral particle, a polarized exciton confined to a semiconductor quantum ring. We predict that this magnetic-field induced phase may strongly affect excitons in a system with cylindrical symmetry, resulting in switching between ``bright'' exciton ground states and novel ``dark'' states with nearly infinite lifetimes. Since excitons determine the optical response of semiconductors, the predicted phase can be used to tailor photon emission from quantum nanostructures.
Spin Accumulation in a Double Quantum Dot Aharonov-Bohm Interferometer
Institute of Scientific and Technical Information of China (English)
YIN Hai-Tao; L(U) Tian-Quan; LIU Xiao-Jie; XUE Hui-Jie
2009-01-01
@@ We investigate the spin accumulation in a double quantum dot Aharonov-Bohm (AB) interferometer in which both the Rashba spin-orbit (RSO) interaction and intradot Coulomb interaction are taken into account. Due to the existence of the RSO interaction, the electron, flowing through different arms of the AB ring, will acquire a spin-dependent phase factor in the tunnel-coupling strengths. This phase factor will induce various interesting interference phenomena. It is found that the electrons of the different spin directions can accumulate in the two dots by properly adjusting the bias and the intradot level with a fixed RSO interaction strength. Moreover, both the magnitude and direction of the spin accumulation in each dot can be conveniently controlled and tuned by the gate voltage acting on the dot or the bias on the lead.
Spin-polarized quantum transport through an Aharonov-Bohm quantum-dot-ring
Institute of Scientific and Technical Information of China (English)
Wang Jian-Ming; Wang Rui; Liang Jiu-Qing
2007-01-01
In this paper the quantum transport through an Aharonov-Bohm (AB) quantum-dot-ring with two dot-array arms described by a single-band tight-binding Hamiltonian is investigated in the presence of additional magnetic fields applied to the dot-array arms to produce spin flip of electrons. A far richer interference pattern than that in the charge transport alone is found. Besides the usual AB oscillation the tunable spin polarization of the current by the magnetic flux is a new observation and is seen to be particularly useful in technical applications. The spectrum of transmission probability is modulated by the quantum dot numbers on the up-arc and down-arc of the ring, which, however, does not affect the period of the AB oscillation.
Aharonov-Bohm effect in the tunnelling of a quantum rotor in a linear Paul trap
Noguchi, Atshushi; Toyoda, Kenji; Urabe, Shinji
2014-01-01
Quantum tunnelling is a common fundamental quantum-mechanical phenomenon that originates from the wave-like characteristics of quantum particles. Although the quantum-tunnelling effect was first observed 85 years ago, some questions regarding the dynamics of quantum tunnelling remain unresolved. Here, we realise a quantum-tunnelling system using two-dimensional ionic structures in a linear Paul trap. We demonstrate that the charged particles in this quantum-tunnelling system are coupled to the vector potential of a magnetic field throughout the entire process, even during quantum tunnelling, as indicated by the manifestation of the Aharonov-Bohm effect in this system. The tunnelling rate of the structures periodically depends on the strength of the magnetic field, whose period is the same as the magnetic-flux quantum $\\phi_0$ through the rotor [($0.99 \\pm 0.07)\\times \\phi_0$].
Singularity and Bohm criterion in hot positive ion species in the electronegative ion sources
Aslaninejad, Morteza; Yasserian, Kiomars
2016-05-01
The structure of the discharge for a magnetized electronegative ion source with two species of positive ions is investigated. The thermal motion of hot positive ions and the singularities involved with it are taken into account. By analytical solution of the neutral region, the location of the singular point and also the values of the plasma parameter such as electric potential and ion density at the singular point are obtained. A generalized Bohm criterion is recovered and discussed. In addition, for the non-neutral solution, the numerical method is used. In contrast with cold ion plasma, qualitative changes are observed. The parameter space region within which oscillations in the density and potential can be observed has been scanned and discussed. The space charge behavior in the vicinity of edge of the ion sources has also been discussed in detail.
Aharonov-Bohm oscillations with period hc/4e and negative magnetoresistance in dirty superconductors
International Nuclear Information System (INIS)
We show that in a disordered superconductor near the superconductor-to-insulator transition the local superfluid density Ns fluctuates from point to point in sign as well as magnitude. We demonstrate this explicitly with a simple model in which correlation effects produce a negative Josephson coupling between two superconducting grains. We argue more generally that correlation effects and resistance fluctuations produce random signs of Ns. This implies that the superconductor-to-insulator transition may not be in the same universality class as the Bose-superfluid--to--insulator transition. It also results in a hc/4e period of Aharonov-Bohm oscillations and a negative magnetoresistance; both occur for T>Tc in superconducting samples and at low temperatures in insulating samples
Energy Technology Data Exchange (ETDEWEB)
Kivelson, S.A. (Department of Physics, University of California Los Angeles, Los Angeles, California 90024 (United States)); Spivak, B.Z. (Physics Department, University of Washington, Seattle, Washington 98195 (United States))
1992-05-01
We show that in a disordered superconductor near the superconductor-to-insulator transition the local superfluid density {ital N}{sub {ital s}} fluctuates from point to point in sign as well as magnitude. We demonstrate this explicitly with a simple model in which correlation effects produce a negative Josephson coupling between two superconducting grains. We argue more generally that correlation effects and resistance fluctuations produce random signs of {ital N}{sub {ital s}}. This implies that the superconductor-to-insulator transition may not be in the same universality class as the Bose-superfluid--to--insulator transition. It also results in a {ital hc}/4{ital e} period of Aharonov-Bohm oscillations and a negative magnetoresistance; both occur for {ital T}{gt}{ital T}{sub {ital c}} in superconducting samples and at low temperatures in insulating samples.
Combined Aharonov-Bohm and Zeeman spin-polarization effects in a double quantum dot ring
International Nuclear Information System (INIS)
A mesoscale Aharonov-Bohm (AB) ring with a quantum dot (QD) embedded in each arm is computationally modeled for unique transmission properties arising from a combination of AB effects and Zeeman splitting of the QD energy levels. A tight-binding Hamiltonian is solved, providing analytical expressions for the transmission as a function of system parameters. Transmission resonances with spin-polarized output are presented for cases involving either a perpendicular field, or a parallel field, or both. The combination of the AB-effect with Zeeman splitting allows sensitive control of the output resonances of the device, manifesting in spin-polarized states which separate and cross as a function of applied field. In the case with perpendicular flux, the AB-oscillations exhibit atypical non-periodicity, and Fano-type resonances appear as a function of magnetic flux due to the flux-dependent shift in the QD energy levels via the Zeeman effect.
Nonlocal Andreev reflection and spin current in a three-terminal Aharonov–Bohm interferometer
International Nuclear Information System (INIS)
This paper theoretically reports the nonlocal Andreev reflection and spin current in a normal metal-ferromagnetic metal-superconducting Aharonov–Bohm interferometer. It is found that the electronic current and spin current are sensitive to systematic parameters, such as the gate voltage of quantum dots and the external magnetic flux. The electronic current in the normal metal lead results from two competing processes: quasiparticle transmission and nonlocal Andreev reflection. The appearance of zero spin-up electronic current (or spin-down electronic current) signals the existence of nonlocal Andreev reflection, and the presence of zero electronic current results in the appearance of pure spin current. (condensed matter: electronic structure, electrical, magnetic, and optical properties)
Transmission through a quantum dot molecule embedded in an Aharonov-Bohm interferometer
Energy Technology Data Exchange (ETDEWEB)
Lovey, Daniel A; Gomez, Sergio S; Romero, Rodolfo H, E-mail: rhromero@exa.unne.edu.ar [Instituto de Modelado e Innovacion Tecnologica, CONICET, and Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Avenida Libertad 5500 (3400) Corrientes (Argentina)
2011-10-26
We study theoretically the transmission through a quantum dot molecule embedded in the arms of an Aharonov-Bohm four quantum dot ring threaded by a magnetic flux. The tunable molecular coupling provides a transmission pathway between the interferometer arms in addition to those along the arms. From a decomposition of the transmission in terms of contributions from paths, we show that antiresonances in the transmission arise from the interference of the self-energy along different paths and that application of a magnetic flux can produce the suppression of such antiresonances. The occurrence of a period of twice the quantum of flux arises at the opening of the transmission pathway through the dot molecule. Two different connections of the device to the leads are considered and their spectra of conductance are compared as a function of the tunable parameters of the model. (paper)
Multiple-path Quantum Interference Effects in a Double-Aharonov-Bohm Interferometer
Directory of Open Access Journals (Sweden)
Yang XF
2010-01-01
Full Text Available Abstract We investigate quantum interference effects in a double-Aharonov-Bohm (AB interferometer consisting of five quantum dots sandwiched between two metallic electrodes in the case of symmetric dot-electrode couplings by the use of the Green’s function equation of motion method. The analytical expression for the linear conductance at zero temperature is derived to interpret numerical results. A three-peak structure in the linear conductance spectrum may evolve into a double-peak structure, and two Fano dips (zero conductance points may appear in the quantum system when the energy levels of quantum dots in arms are not aligned with one another. The AB oscillation for the magnetic flux threading the double-AB interferometer is also investigated in this paper. Our results show the period of AB oscillation can be converted from 2π to π by controlling the difference of the magnetic fluxes threading the two quantum rings.
The Role of Tusi-Bohm Planetarium in Astronomy Outreach in Azerbaijan
Mustafa, Famil
2015-08-01
Tusi-Bohm Planetarium was built in 2010 by businessman and amateur astronomer Tahir Gozal. Lectures on various fields of astronomy are offered in Planetarium. Each year, school pupils takes an active place on activities such as, International Day of Planetarium, Sun-Earth Day, Yuri's Night, World Space Week, Global Astronomy Month, and etc., organized by the Planetarium. School pupils and students are often meet astronomers at the Planetarium and during the meetings, astronomers provides detailed information about telescopes, space and astronomy. During special nights which organized by Planetarium and amateur astronomers visitors can observe sky with telescopes. All above mentioned activities are widely spreading on the media. As a result of these association, schools have already bought their own telescopes and started their study groups at school.
Probing the noncommutative effects of phase space in the time-dependent Aharonov-Bohm effect
Ma, Kai; Yang, Huan-Xiong
2016-01-01
We study the noncommutative corrections on the time-dependent Aharonov-Bohm effect when both the coordinate-coordinate and momentum-momentum noncommutativities are considered. This study is motivated by the recent observation that there is no net phase shift in the time-dependent AB effect on the ordinary space, and therefore tiny derivation from zero can indicate new physics. The vanishing of the time-dependent AB phase shift on the ordinary space is preserved by the gauge and Lorentz symmetries. However, on the noncomutative phase space, while the ordinary gauge symmetry can be kept by the Seiberg-Witten map, but the Lorentz symmetry is broken. Therefore nontrivial noncommutative corrections are expected. We find there are three kinds of noncommutative corrections in general: 1) $\\xi$-dependent correction which comes from the noncommutativity among momentum operators; 2) momentum-dependent correction which is rooted in the nonlocal interactions in the noncommutative extended model; 3) momentum-independent c...
Forward-smooth high-order uniform Aharonov–Bohm asymptotics
Berry, M. V.
2016-07-01
The Aharonov–Bohm (AB) function, describing a plane wave scattered by a flux line, is expanded asymptotically in a Fresnel-integral based series whose terms are smooth in the forward direction and uniformly valid in angle and flux. Successive approximations are valid for large distance r from the flux (or short wavelength) but are accurate even within one wavelength of it. Coefficients of all the terms are exhibited explicitly for the forward direction, enabling the high-order asymptotics to be understood in detail. The series is factorally divergent, with optimal truncation error exponentially small in r. Systematic resummation gives further exponential improvement. Terms of the series satisfy a resurgence relation: the high orders are related to the low orders. Discontinuities in the backward direction get smaller order by order, with systematic cancellation by successive terms. The relation to an earlier scheme based on the Cornu spiral is discussed.
Vacuum polarization of planar charged fermions with Coulomb and Aharonov-Bohm potentials
Khalilov, V. R.; Mamsurov, I. V.
2016-02-01
Vacuum polarization of charged massless fermions is investigated in the superposition of Coulomb and Aharonov-Bohm (AB) potentials in 2 + 1 dimensions. For this purpose, we construct the Green function of the two-dimensional Dirac equation with Coulomb and AB potentials (via the regular and irregular solutions of the radial Dirac equation) and then calculate the vacuum polarization charge density in the so-called subcritical and supercritical regimes. In the supercritical regime, the Green function has a discontinuity in the complex plane of “energy” due to the singularities on the negative energy axis; these singularities are situated on the unphysical sheet and related to the creation of infinitely many quasistationary fermionic states with negative energies. We expect that our results will be helpful in gaining deeper understanding of the fundamental problem of quantum electrodynamics which can be applied to the problems of charged impurity screening in graphene taking into consideration the electron spin.
Popescu-Rohrlich Boxes in Quantum Measure Theory
Barnett, Matthew; Dowker, Fay; Rideout, David
2006-01-01
Two results are proved at the quantal level in Sorkin's hierarchy of measure theories. One is a strengthening of an existing bound on the correlations in the EPR-Bohm setup under the assumption that the probabilities admit a strongly positive joint quantal measure. It is also proved that any set of no-signalling probabilities, for two distant experimenters with a choice of two alternative experiments each and two possible outcomes per experiment, admits a joint quantal measure, though one tha...
Stable and Metastable Cosmic Strings in Heterotic M-Theory
Buchbinder, Evgeny I.
2006-01-01
We address the question of finding stable and metastable cosmic strings in quasi-realistic heterotic M-theory compactifications with stabilized moduli. According to Polchinski's conjecture, the only stable strings in the absence of massless fields are Aharonov-Bohm strings. Such strings could potentially be created in heterotic compactifications as bound states of open membranes, five-branes wrapped on four-cycles and solitonic strings. However, in generic compactifications, the process of mo...
International Nuclear Information System (INIS)
Full text: We study the charge persistent current (PC) in a one dimensional mesoscopic ring pierced by Aharonov-Bohm-Casher fluxes coupled to a side-branch quantum dot with a singly occupied level at Kondo resonance. For privileged values of the fluxes the problem can be mapped onto an integrable model, exactly solvable by a Bethe ansatz. In the case of a pure magnetic Aharonov-Bohm flux, we find - contrary to recent claims in the literature - that the presence of the quantum dot has no effect on the PC. In contrast, the Kondo resonance interferes with the spin-dependent Aharonov-Casher effect to induce a term in the PC that scales as 1/N in the strong coupling regime, with N the number of electrons in the ring
Energy Technology Data Exchange (ETDEWEB)
Xie, Wenfang, E-mail: xiewf@vip.163.com [School of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510006 (China)
2013-05-03
The photoionization cross section (PCS) associated with intersubband transitions in quantum rings which include a repulsive scattering centre is investigated for the case with the presence of an external magnetic field. Calculations are carried out by using the matrix diagonalization method of the Hamiltonian matrix within the effective-mass approximation. Our results show that both the magnetic field, the ring radius and the impurity can affect the PCS of quantum rings. In addition, we found that the resonant peak of the PCS shows the Aharonov–Bohm oscillation with changing the magnetic field and the ring radius. Moreover, the width of the ring can influence the Aharonov–Bohm oscillation in peak while the resonant peak value of the PCS decreases as the ring width increases in the same ring geometry.
International Nuclear Information System (INIS)
The photoionization cross section (PCS) associated with intersubband transitions in quantum rings which include a repulsive scattering centre is investigated for the case with the presence of an external magnetic field. Calculations are carried out by using the matrix diagonalization method of the Hamiltonian matrix within the effective-mass approximation. Our results show that both the magnetic field, the ring radius and the impurity can affect the PCS of quantum rings. In addition, we found that the resonant peak of the PCS shows the Aharonov–Bohm oscillation with changing the magnetic field and the ring radius. Moreover, the width of the ring can influence the Aharonov–Bohm oscillation in peak while the resonant peak value of the PCS decreases as the ring width increases in the same ring geometry.
Moulopoulos, Konstantinos
2010-01-01
We show that the standard Dirac phase factor is not the only solution of the gauge transformation equations. The full form of a general gauge function (that connects systems that move in different sets of scalar and vector potentials), apart from Dirac phases also contains terms of classical fields that act nonlocally (in spacetime) on the local solutions of the time-dependent Schr\\"odinger equation: the phases of wavefunctions in the Schr\\"odinger picture are affected nonlocally by spatially and temporally remote magnetic and electric fields, in ways that are fully explored. These contributions go beyond the usual Aharonov-Bohm effects (magnetic or electric). (i) Application to cases of particles passing through static magnetic or electric fields leads to cancellations of Aharonov-Bohm phases at the observation point; these are linked to behaviors at the semiclassical level (to the old Werner & Brill experimental observations, or their "electric analogs" - or to recent reports of Batelaan & Tonomura)...
2D Pauli Equation with Hulthén Potential in the Presence of Aharonov-Bohm Effect
Institute of Scientific and Technical Information of China (English)
N.Ferkous; A.Bounames
2013-01-01
The 2D Pauli equation with Hulthén potential for spin-1/2 particle in the presence of Aharonov-Bohm (AB) field is solved analytically,on the assumption that an effective approximation is used for the centrifugai term.Singular and regular solutions of the problem are obtained.It is shown that the AB field lifts the degeneracy of the energy levels.The range of the flux parameter for which singular solutions are allowed is modified compared to the pure AB case.When the screening parameter vanishes,it is shown that the obtained energy spectrum becomes the same as that of the Aharonov-Bohm Coulomb problem.
Institute of Scientific and Technical Information of China (English)
CHEN Bao-Ju; CHEN Xiong-Wen; SHI Zhen-Gang; ZHU Xi-Xiang; SONG Ke-Hui; WU Shao-Quan
2007-01-01
We theoretically investigate the properties of the ground state of the strongly correlated T-shaped double quantum dots embedded in an Aharonov-Bohm ring in the Kondo regime by means of the one-impurity Anderson Hamiltonian.It is found that in this system,the persistent current depends sensitively on the parity and size of the ring.With the increase of interdot coupling,the persistent current is suppressed due to the enhancing Fano interference weakening the Kondo effect.Moreover,when the spin of quantum dot embedded in the aharonovBohm ring is screened,the persistent current peak is not affected by interdot coupling.Thus this model may be a new candidate for detecting Kondo screening cloud.
Maslov, A. V.; Citrin, D. S.
2003-03-01
This work demonstrates that the Aharonov-Bohm effect for excitons, practically indistinguishable from the numerical noise without an applied electric field, becomes clearly evident in the optical absorption once the electric field is applied in the plane containing the nanoring. The enhancement arises as a result of the field-induced delocalization of the relative electron-hole motion around the entire ring. The excitonic effects are essential to describe even qualitatively the absorption spectra.
Grochol, Michal; Zimmermann, Roland
2007-01-01
Transition energies and oscillator strengths of excitons in dependence on magnetic field are investigated in type I and II semiconductor nanorings. A slight deviation from circular (concentric) shape of the type II nanoring gives a better observability of the Aharonov-Bohm oscillations since the ground state is always optically active. Kinetic equations for the exciton occupation are solved with acoustic phonon scattering as the major relaxation process, and absorption and luminescence spectr...
International Nuclear Information System (INIS)
In a previous paper, we found the most general boundary conditions for the Aharonov-Bohm scattering of a Dirac particle. We found the resulting wave functions but we did not worry about delta normalizing them. As is well know, in practice, it is not easy to evaluate the diverging integrals occurring in the process. The purpose of this paper is to evaluate those integrals and present the resulting delta normalized eigenfunctions. (author)
Sameer M. Ikhdair; Falaye, Babatunde J.
2014-01-01
The two-dimensional solution of the spinless Klein–Gordon (KG) equation for scalar–vector harmonic oscillator potentials with and without the presence of constant perpendicular magnetic and Aharonov–Bohm (AB) flux fields is studied within the asymptotic function analysis and Nikiforov–Uvarov (NU) method. The exact energy eigenvalues and normalized wave functions are analytically obtained in terms of potential parameters, magnetic field strength, AB flux field and magnetic quantum number. The ...
A charged particle in a homogeneous magnetic field accelerated by a time-periodic Aharonov-Bohm flux
International Nuclear Information System (INIS)
We consider a nonrelativistic quantum charged particle moving on a plane under the influence of a uniform magnetic field and driven by a periodically time-dependent Aharonov-Bohm flux. We observe an acceleration effect in the case when the Aharonov-Bohm flux depends on time as a sinusoidal function whose frequency is in resonance with the cyclotron frequency. In particular, the energy of the particle increases linearly for large times. An explicit formula for the acceleration rate is derived with the aid of the quantum averaging method, and then it is checked against a numerical solution and a very good agreement is found. - Highlights: → A nonrelativistic quantum charged particle on a plane. → A homogeneous magnetic field and a periodically time-dependent Aharonov-Bohm flux. → The quantum averaging method applied to a time-dependent system. → A resonance of the AB flux with the cyclotron frequency. → An acceleration with linearly increasing energy; a formula for the acceleration rate.
International Nuclear Information System (INIS)
This Letter extends our probabilistic framework for two-player quantum games to the multiplayer case, while giving a unified perspective for both classical and quantum games. Considering joint probabilities in the Einstein-Podolsky-Rosen-Bohm (EPR-Bohm) setting for three observers, we use this setting in order to play general three-player noncooperative symmetric games. We analyze how the peculiar non-factorizable joint probabilities provided by the EPR-Bohm setting can change the outcome of a game, while requiring that the quantum game attains a classical interpretation for factorizable joint probabilities. In this framework, our analysis of the three-player generalized Prisoner's Dilemma (PD) shows that the players can indeed escape from the classical outcome of the game, because of non-factorizable joint probabilities that the EPR setting can provide. This surprising result for three-player PD contrasts strikingly with our earlier result for two-player PD, played in the same framework, in which even non-factorizable joint probabilities do not result in escaping from the classical consequence of the game
A possible realization of Einstein's causal theory underlying quantum mechanics
International Nuclear Information System (INIS)
It is shown that a new microscopic mechanics formulated earlier can be looked upon as a possible causal theory underlying quantum mechanics, which removes Einstein's famous objections against quantum theory. This approach is free from objections raised against Bohm's hidden variable theory and leads to a clear physical picture in terms of familiar concepts, if self interactions are held responsible for deviations from classical behaviour. The new level of physics unfolded by this approach may reveal novel frontiers in high-energy physics. (author)
Creation of planar charged fermions in Coulomb and Aharonov-Bohm potentials
Energy Technology Data Exchange (ETDEWEB)
Khalilov, V.R. [Moscow State University, Faculty of Physics, Moscow (Russian Federation)
2013-08-15
The creation of charged fermions from the vacuum by a Coulomb field in the presence of an Aharonov-Bohm (AB) potential are studied in 2+1 dimensions. The process is governed by a (singular) Dirac Hamiltonian that requires the supplementary definition in order for it to be treated as a self-adjoint quantum-mechanical operator. By constructing a one-parameter self-adjoint extension of the Dirac Hamiltonian, specified by boundary conditions, we describe the (virtual bound) quasistationary states with ''complex energy'' emerging in an attractive Coulomb potential, derive for the first time, complex equations (depending upon the electron spin and the extension parameter) for the quasistationary state ''complex energy''. The constructed self-adjoint Dirac Hamiltonians in Coulomb and AB potentials are applied to provide a correct description to the low-energy electron excitations, as well as the creation of charged quasiparticles from the vacuum in graphene by the Coulomb impurity in the presence of AB potential. It is shown that the strong Coulomb field can create charged fermions for some range of the extension parameter. (orig.)
Spin Filter Based on an Aharonov–Bohm Interferometer with Rashba Spin–Orbit Effect
International Nuclear Information System (INIS)
We propose a spin filter based on both the quantum interference and the Rashba spin–orbit (RSO) effects. This spin filter consists of a Aharonov–Bohm (AB) interferometer with two quantum dots (QDs) inserted in its arms. The influences of a magnetic flux φ threading through the AB ring and the RSO interaction inside the two QDs are taken into account by using the nonequilibrium Green's function technique. Due to the existence of the RSO interaction, the electrons flowing through different arms of the ring will acquire a spin-dependent phase factor in the linewidth matrix elements. This phase factor, combined with the influence of the magnetic flux, will induce a spin-dependent electron transport through the device. Moreover, we show that by tuning the magnetic flux, the RSO strength and the inter-dot tunnelling coupling strength, a pure spin-up or spin-down conductance can be obtained when a spin-unpolarized current is injected from the external leads, which can be used to filter the electron spin. (condensed matter: electronic structure, electrical, magnetic, and optical properties)
Analytical expression of Kondo temperature in quantum dot embedded in Aharonov-Bohm ring.
Yoshii, Ryosuke; Eto, Mikio
2011-01-01
We theoretically study the Kondo effect in a quantum dot embedded in an Aharonov-Bohm ring, using the "poor man's" scaling method. Analytical expressions of the Kondo temperature TK are given as a function of magnetic flux Φ penetrating the ring. In this Kondo problem, there are two characteristic lengths, Lc=ℏvF∕|ε̃0| and LK = ħvF = TK, where vF is the Fermi velocity and ε̃0 is the renormalized energy level in the quantum dot. The former is the screening length of the charge fluctuation and the latter is that of the spin fluctuation, i.e., size of Kondo screening cloud. We obtain diferent expressions of TK(Φ) for (i) Lc ≪ LK ≪ L, (ii) Lc ≪ L ≪ LK, and (iii) L ≪ Lc ≪ LK, where L is the size of the ring. TK is remarkably modulated by Φ in cases (ii) and (iii), whereas it hardly depends on Φ in case (i).PACS numbers: PMID:22112300
Bound states of massive fermions in Aharonov-Bohm-like fields
Energy Technology Data Exchange (ETDEWEB)
Khalilov, V.R. [Moscow State University, Faculty of Physics, Moscow (Russian Federation)
2014-01-15
Bound states of massive fermions in Aharonov-Bohm (AB)-like fields have analytically been studied. The Hamiltonians with the (AB)-like potentials are essentially singular and therefore require specification of a one-parameter self-adjoint extension. We construct self-adjoint Dirac Hamiltonians with the AB potential in 2+1 dimensions that are specified by boundary conditions at the origin. It is of interest that for some range of the extension parameter the AB potential can bind relativistic charged massive fermions. The bound-state energy is determined by the AB magnetic flux and depends upon the fermion spin and extension parameter; it is a periodical function of the magnetic flux. We also construct self-adjoint Hamiltonians for the so-called Aharonov-Casher (AC) problem, show that nonrelativistic neutral massive fermions can be bound by the (AC) background, determine the range of the extension parameter in which fermion bound states exist, and find their energies as well as wave functions. (orig.)
On the relation between the Feynman paradox and the Aharonov–Bohm effects
International Nuclear Information System (INIS)
The magnetic Aharonov–Bohm (A–B) effect occurs when a point charge interacts with a line of magnetic flux, while its reciprocal, the Aharonov–Casher (A–C) effect, occurs when a magnetic moment interacts with a line of charge. For the two interacting parts of these physical systems, the equations of motion are discussed in this paper. The generally accepted claim is that both parts of these systems do not accelerate, while Boyer has claimed that both parts of these systems do accelerate. Using the Euler–Lagrange equations we predict that in the case of unconstrained motion, only one part of each system accelerates, while momentum remains conserved. This prediction requires a time-dependent electromagnetic momentum. For our analysis of unconstrained motion, the A–B effects are then examples of the Feynman paradox. In the case of constrained motion, the Euler–Lagrange equations give no forces, in agreement with the generally accepted analysis. The quantum mechanical A–B and A–C phase shifts are independent of the treatment of constraint. Nevertheless, experimental testing of the above ideas and further understanding of the A–B effects that are central to both quantum mechanics and electromagnetism could be possible. (paper)
Creation of planar charged fermions in Coulomb and Aharonov-Bohm potentials
Khalilov, V R
2013-01-01
The creation of charged fermions from the vacuum by a Coulomb field in the presence of an Aharonov--Bohm (AB) potential are studied in 2+1 dimensions. The process is governed by a (singular) Dirac Hamiltonian that requires the supplementary definition in order for it to be treated as a self-adjoint quantum-mechanical operator. By constructing a one-parameter self-adjoint extension of the Dirac Hamiltonian, specified by boundary conditions, we describe the (virtual bound) quasistationary states with "complex energy" emerging in an attractive Coulomb potential, derive for the first time, complex equations (depending upon the electron spin and the extension parameter) for the quasistationary state "complex energy". The constructed self-adjoint Dirac Hamiltonians in Coulomb and AB potentials are applied to provide a correct description to the low-energy electron excitations, as well as the creation of charged quasiparticles from the vacuum in graphene by the Coulomb impurity in the presence of AB potential. It is...
Effect of vacuum polarization of charged massive fermions in an Aharonov-Bohm field
Energy Technology Data Exchange (ETDEWEB)
Khalilov, V.R. [M.V. Lomonosov Moscow State University, Faculty of Physics, Moscow (Russian Federation)
2014-09-15
The effect of vacuum polarization of charged massive fermions in an Aharonov-Bohm (AB) potential in 2 + 1 dimensions is investigated. The causal Green function of the Dirac equation with the AB potential is represented via the regular and irregular solutions of the two-dimensional radial Dirac equation. It is shown that the vacuum current density contains the contribution from free filled states of the negative energy continuum as well as that from a bound unfilled state, which can emerge in the above background due to the interaction of the fermion's spin magnetic moment with the AB magnetic field, while the induced charge density contains only the contribution from the bound state. The expressions for the vacuum charge and induced current densities are obtained (recovered for massless fermions) for the graphene in the field of infinitesimally thin solenoid perpendicular to the plane of a sample. We also find the bound state energy as a function of magnetic flux, fermion spin, and the radius of solenoid, and we discuss the role of the so-called self-adjoint extension parameter and determine it in terms of the physics of the problem. (orig.)
A solenoidal synthetic field and the non-Abelian Aharonov-Bohm effects in neutral atoms.
Huo, Ming-Xia; Nie, Wei; Hutchinson, David A W; Kwek, Leong Chuan
2014-01-01
Cold neutral atoms provide a versatile and controllable platform for emulating various quantum systems. Despite efforts to develop artificial gauge fields in these systems, realizing a unique ideal-solenoid-shaped magnetic field within the quantum domain in any real-world physical system remains elusive. Here we propose a scheme to generate a "hairline" solenoid with an extremely small size around 1 micrometer which is smaller than the typical coherence length in cold atoms. Correspondingly, interference effects will play a role in transport. Despite the small size, the magnetic flux imposed on the atoms is very large thanks to the very strong field generated inside the solenoid. By arranging different sets of Laguerre-Gauss (LG) lasers, the generation of Abelian and non-Abelian SU(2) lattice gauge fields is proposed for neutral atoms in ring- and square-shaped optical lattices. As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells. During the evolution, the quantum coherence is maintained and the atoms are exposed to a large magnetic flux. The scheme requires only standard optical access, and is robust to weak particle interactions. PMID:25103877
Spin Filter Based on an Aharonov-Bohm Interferometer with Rashba Spin-Orbit Effect
Institute of Scientific and Technical Information of China (English)
FANG Ming; SUN Lian-Liang
2008-01-01
We propose a spin filter based on both the quantum interference and the Rashba spin-orbit (RSO) effects. This spin filter consists of a Aharonov-Bohm (AB) interferometer with two quantum dots (QDs) inserted in its arms.The influences of a magnetic flux ψ threading through the AB ring and the RSO interaction inside the two QDs are taken into account by using the nonequilibrium Green's function technique. Due to the existence of the RSO interaction, the electrons flowing through different arms of the ring will acquire a spin-dependent phase factor in the linewidth matrix elements. This phase factor, combined with the influence of the magnetic flux, will induce a spin-dependent electron transport through the device. Moreover, we show that by tuning the magnetic flux,the RSO strength and the inter-dot tunnelling coupling strength, a pure spin-up or spin-down conductance can be obtained when a spin-unpolarized current is injected from the external leads, which can be used to filter the electron spin.
Valley Zeeman energy in monolayer MoS2 quantum rings: Aharonov-Bohm effect
Oliveira, D.; Fu, Jiyong; Villegas-Lelovsky, L.; Dias, A. C.; Qu, Fanyao
2016-05-01
We investigate the valley Zeeman energy (VZE) in monolayer MoS2 quantum rings, subjected to a magnetic flux Φ only passing through a hole region enclosed by the inner circle of the ring. To gain insight on our numerical outcomes for finite two-dimensional rings, an analytic solution in the one-dimensional limit (zero ring width) is also presented. Although no magnetic field is applied inside the ring region, we observe finite VZEs. Interestingly, in contrast to the usual linear scenario, the VZE of the rings exhibits an oscillatory dependence on Φ with possible vanishing valley Zeeman effect even in a nonzero magnetic flux due to Aharonov-Bohm type effect. On the other hand, within one period of oscillations the VZE increases linearly with Φ . Furthermore, for a given magnetic flux, the valley Zeeman effect is more pronounced in a ring with a stronger quantum confinement. Thus the VZE can be tuned by either magnetic flux or ring confinement or both of them. This opens a new route for controlling the valley Zeeman effect using a nonmagnetic means.
On Entropy Production in the Madelung Fluid and the Role of Bohm's Potential in Classical Diffusion
Heifetz, Eyal; Tsekov, Roumen; Cohen, Eliahu; Nussinov, Zohar
2016-04-01
The Madelung equations map the non-relativistic time-dependent Schrödinger equation into hydrodynamic equations of a virtual fluid. While the von Neumann entropy remains constant, we demonstrate that an increase of the Shannon entropy, associated with this Madelung fluid, is proportional to the expectation value of its velocity divergence. Hence, the Shannon entropy may grow (or decrease) due to an expansion (or compression) of the Madelung fluid. These effects result from the interference between solutions of the Schrödinger equation. Growth of the Shannon entropy due to expansion is common in diffusive processes. However, in the latter the process is irreversible while the processes in the Madelung fluid are always reversible. The relations between interference, compressibility and variation of the Shannon entropy are then examined in several simple examples. Furthermore, we demonstrate that for classical diffusive processes, the "force" accelerating diffusion has the form of the positive gradient of the quantum Bohm potential. Expressing then the diffusion coefficient in terms of the Planck constant reveals the lower bound given by the Heisenberg uncertainty principle in terms of the product between the gas mean free path and the Brownian momentum.
A solenoidal synthetic field and the non-Abelian Aharonov-Bohm effects in neutral atoms
Huo, Ming-Xia; Nie, Wei; Hutchinson, David A. W.; Kwek, Leong Chuan
2014-08-01
Cold neutral atoms provide a versatile and controllable platform for emulating various quantum systems. Despite efforts to develop artificial gauge fields in these systems, realizing a unique ideal-solenoid-shaped magnetic field within the quantum domain in any real-world physical system remains elusive. Here we propose a scheme to generate a ``hairline'' solenoid with an extremely small size around 1 micrometer which is smaller than the typical coherence length in cold atoms. Correspondingly, interference effects will play a role in transport. Despite the small size, the magnetic flux imposed on the atoms is very large thanks to the very strong field generated inside the solenoid. By arranging different sets of Laguerre-Gauss (LG) lasers, the generation of Abelian and non-Abelian SU(2) lattice gauge fields is proposed for neutral atoms in ring- and square-shaped optical lattices. As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells. During the evolution, the quantum coherence is maintained and the atoms are exposed to a large magnetic flux. The scheme requires only standard optical access, and is robust to weak particle interactions.
Effect of vacuum polarization of charged massive fermions in an Aharonov-Bohm field
International Nuclear Information System (INIS)
The effect of vacuum polarization of charged massive fermions in an Aharonov-Bohm (AB) potential in 2 + 1 dimensions is investigated. The causal Green function of the Dirac equation with the AB potential is represented via the regular and irregular solutions of the two-dimensional radial Dirac equation. It is shown that the vacuum current density contains the contribution from free filled states of the negative energy continuum as well as that from a bound unfilled state, which can emerge in the above background due to the interaction of the fermion's spin magnetic moment with the AB magnetic field, while the induced charge density contains only the contribution from the bound state. The expressions for the vacuum charge and induced current densities are obtained (recovered for massless fermions) for the graphene in the field of infinitesimally thin solenoid perpendicular to the plane of a sample. We also find the bound state energy as a function of magnetic flux, fermion spin, and the radius of solenoid, and we discuss the role of the so-called self-adjoint extension parameter and determine it in terms of the physics of the problem. (orig.)
International Nuclear Information System (INIS)
We show that the standard Dirac phase factor is not the only solution of the usual gauge transformation equations. The full form of a general gauge function (that connects systems that move in different sets of scalar and vector potentials), apart from Dirac phases (spatial or temporal integrals over potentials), also contains terms of classical fields that act nonlocally (in spacetime) on the local solutions of the time-dependent Schroedinger equation. As a result, the phases of wavefunctions in the Schroedinger picture are affected nonlocally by spatially and temporally remote magnetic and electric fields, in specific ways that are fully explored. These contributions go beyond the usual Aharonov-Bohm effects (magnetic or electric). (i) Application to cases of particles passing through full static magnetic or electric fields leads to cancellations of Aharonov-Bohm phases at the observation point; these cancellations are linked to behaviors at the semiclassical level (i.e. the old Werner and Brill experimental observations, or their 'electric analogs'-or to more recent reports of Batelaan and Tonomura) but are shown to be far more general (true not only for narrow wavepackets but also for completely delocalized (spread-out) quantum states). By using these cancellations, certain previously unnoticed sign-errors in the literature are corrected. (ii) Application to time-dependent situations provides a remedy for erroneous results in the literature (concerning an uncritical use of Dirac phase factors) and leads to phases that contain an Aharonov-Bohm part and a field-nonlocal part: their competition is shown to recover relativistic causality in earlier 'paradoxes' (such as the van Kampen thought-experiment), while a more general consideration indicates that the temporal nonlocalities found here demonstrate in part a causal propagation of phases of quantum mechanical wavefunctions in the Schroedinger picture. This may open a new and direct way to address time
Schütz, G; Rembold, A; Pooch, A; Prochel, H; Stibor, A
2015-11-01
We propose an experiment for the first proof of the type I electric Aharonov-Bohm effect in an ion interferometer for hydrogen. The performances of three different beam separation schemes are simulated and compared. The coherent ion beam is generated by a single atom tip (SAT) source and separated by either two biprisms with a quadrupole lens, two biprisms with an einzel-lens or three biprisms. The beam path separation is necessary to introduce two metal tubes that can be pulsed with different electric potentials. The high time resolution of a delay line detector allows to work with a continuous ion beam and circumvents the pulsed beam operation as originally suggested by Aharonov and Bohm. We demonstrate that the higher mass and therefore lower velocity of ions compared to electrons combined with the high expected SAT ion emission puts the direct proof of this quantum effect for the first time into reach of current technical possibilities. Thereby a high detection rate of coherent ions is crucial to avoid long integration times that allow the influence of dephasing noise from the environment. We can determine the period of the expected matter wave interference pattern and the signal on the detector by determining the superposition angle of the coherent partial beams. Our simulations were tested with an electron interferometer setup and agree with the experimental results. We determine the separation scheme with three biprisms to be most efficient and predict a total signal acquisition time of only 80s to measure a phase shift from 0 to 2π due to the electric Aharonov-Bohm effect. PMID:26188995
Spin-polarization-dependent transport in a quantum dot array coupled with an Aharonov—Bohm ring
International Nuclear Information System (INIS)
In this paper the quantum transport in a dot-array coupled with an Aharonov—Bohm (AB) ring is investigated via single-band tight-binding Hamiltonian. It is shown that the output spin current is a periodic function of the magnetic flux in the quantum unit Φ0. The resonance positions of the total transmission probability do not depend on the size of the AB ring but the electronic spectrum. Moreover, the persistent currents in the AB ring is also spin-polarization dependent and different from the isolated AB ring where the persistent current is independent of spin polarization. (condensed matter: electronic structure, electrical, magnetic, and optical properties)
Grochol, Michal; Zimmermann, Roland
2007-11-01
Transition energies and oscillator strengths of excitons in dependence on magnetic field are investigated in types I and II semiconductor nanorings. A slight deviation from circular (concentric) shape of the type II nanoring gives a better observability of the Aharonov-Bohm oscillations since the ground state is always optically active. Kinetic equations for the exciton occupation are solved with acoustic phonon scattering as the major relaxation process, and absorption and luminescence spectra are calculated, showing deviations from equilibrium. The presence of a nonradiative exciton decay leads to a quenching of the integrated photoluminescence with magnetic field.
International Nuclear Information System (INIS)
A detailed study of the quantum modification of acousto-helicon wave spectra due to Bohm potential and Fermi degenerate pressure in colloids laden semiconductor plasma has been presented. We have used quantum hydrodynamic model of plasmas to arrive at most general dispersion relation in presence of magnetic field. This dispersion relation has been analyzed in three different velocity regimes and the expressions for gain constants have been obtained. From the present study it has been concluded that the quantum effect and the magnetic field significantly modify the wave characteristics particularly in high doping regime in semiconductor plasma medium in presence of colloids in it
Induced fermion number, phase-shift flip, and the axial anomaly in the Aharonov-Bohm potential
International Nuclear Information System (INIS)
The spectral properties of the Dirac and the Klein-Gordon equations in the Aharonov-Bohm potential are discussed. The density of states for different self-adjoint extensions is calculated. The presence of the bound state manifests itself by asymmetric differential scattering cross sections. The results are applied to several physical quantities: the total energy, induced fermion-number, and the axial anomaly. The predictions of a persistent current in the presence of a cosmic string and a gravitational vortex are made. (author) 41 refs.; 1 fig
On the Aharonov-Bohm Operators with Varying Poles: The Boundary Behavior of Eigenvalues
Noris, Benedetta; Nys, Manon; Terracini, Susanna
2015-11-01
We consider a magnetic Schrödinger operator with magnetic field concentrated at one point (the pole) of a domain and half integer circulation, and we focus on the behavior of Dirichlet eigenvalues as functions of the pole. Although the magnetic field vanishes almost everywhere, it is well known that it affects the operator at the spectral level (the Aharonov-Bohm effect, Phys Rev (2) 115:485-491, 1959). Moreover, the numerical computations performed in (Bonnaillie-Noël et al., Anal PDE 7(6):1365-1395, 2014; Noris and Terracini, Indiana Univ Math J 59(4):1361-1403, 2010) show a rather complex behavior of the eigenvalues as the pole varies in a planar domain. In this paper, in continuation of the analysis started in (Bonnaillie-Noël et al., Anal PDE 7(6):1365-1395, 2014; Noris and Terracini, Indiana Univ Math J 59(4):1361-1403, 2010), we analyze the relation between the variation of the eigenvalue and the nodal structure of the associated eigenfunctions. We deal with planar domains with Dirichlet boundary conditions and we focus on the case when the singular pole approaches the boundary of the domain: then, the operator loses its singular character and the k-th magnetic eigenvalue converges to that of the standard Laplacian. We can predict both the rate of convergence and whether the convergence happens from above or from below, in relation with the number of nodal lines of the k-th eigenfunction of the Laplacian. The proof relies on the variational characterization of eigenvalues, together with a detailed asymptotic analysis of the eigenfunctions, based on an Almgren-type frequency formula for magnetic eigenfunctions and on the blow-up technique.
Two-factor theory – at the intersection of health care management and patient satisfaction
Bohm J
2012-01-01
Josef BohmHealth Services Administration, New York City College of Technology, City University of New York, Brooklyn, NY, USAAbstract: Using data obtained from the 2004 Joint Canadian/United States Survey of Health, an analytic model using principles derived from Herzberg’s motivational hygiene theory was developed for evaluating patient satisfaction with health care. The analysis sought to determine whether survey variables associated with consumer satisfaction act as Hertzberg fac...
On the microscopic foundation of scattering theory
International Nuclear Information System (INIS)
The aim of the thesis is to give a contribution to the microscopic foundation of scattering theory, i. e. to show, how the asymptotic formalism of scattering theory with objects like the S-matrix as well the initial and final asymptotics ψin and ψout can be derived from a microscopic description of the basic system. First the final statistics from a N-particle system through farly distant surfaces is derived. Thereafter we confine us to the 1-particle scattering and apply the final statistics in order to derive the scattering cross section from a microscopical description of the scattering situation. The basing dynamics are Bohm's mechanics, a theory on the motion of point particles, which reproduces all results of nonrelativistic quantum mechanics
International Nuclear Information System (INIS)
Aharonov-Bohm physics at the two-particle level is investigated for distinguishable interacting charged particles through the exact solution of a toy model with confined states. The effect of the inaccessible magnetic flux is distributed between the center-of-mass and the internal pair level, and the nontrivial manner in which the two levels mutually affect each other demonstrates the interplay between interactions, the nontrivial topology, the Aharonov-Bohm flux and the characteristics of a charged quantal mixture. Analytical expressions for energy spectra, wavefunctions, (flux-dependent) critical interactions for binding and current densities are derived, and these offer the rare possibility of studying persistent currents from the point of view of an interacting nanoscopic system. Two cyclic adiabatic processes are identified, one coupled to the center-of-mass behavior and the other defined on the two-body interaction potential, with the associated Berry's phases also analytically determined; these are found to be directly linked to the electric and probability (persistent) currents in nontrivial ways that are shown to be universal (independent of the actual form of the interaction). The direct connection of the two-body Berry's phase to the electric current for a neutral system is found to disappear in the case of identical particles-hence revealing the character of a charged mixture as being crucial for exhibiting this universal behavior.
"implicate Order" and the Good Life: Applying David Bohm's Ontology in Human World
Ravn, Ib.
In an attempt to formulate a coherent view of quantum reality, the theoretical physicist David Bohm has proposed a new concept of order to supplement the mechanistic Cartesian order of traditional physics. The "implicate" order is a subtler and deeper order that emphasizes "unbroken wholeness in flowing movement," in contrast to the coarser and more superficial, "explicate" Cartesian order of distinct phenomena. This dissertation attempts to develop a meaning for the idea of implicate order in the world of human experience. First is offered an account of some evolutionary episodes in terms of implicate and explicate order which draws on compatible work in cosmology, embryogenesis, visual perception, brain memory, decision making and phenomenology. Two important characteristics of the implicate order are then identified: in an implicate order, the whole is enfolded (or represented) in its parts; and all parts render different perspectives of the whole. Using arguments from decision making, the study of "flow" in human consciousness, and a model of skill acquisition, it is suggested that these characteristics manifest themselves in the human world as the "unity experience" and the "diversity experience," respectively. The former is the experience that a given part of one's life reveals a larger wholeness or unity; the subject-object distinction is transcended and one becomes absorbed in the flow of whatever activity is pursued. The latter is a deep appreciation of the diversity of ways in which people may seek the unity experience. These experiences are proposed as general values: social and psychological conditions ought to be such that these experiences are enhanced in all people. A two-by-two matrix of the two experiences demonstrates the danger of pursuing one to the exclusion of the other. The experience of unity without diversity turns into absolutism, the insistence that one's chosen activities or beliefs are the only right ones. The experience of diversity
Sitenko, Yu. A.
1997-01-01
We consider an analogue of the Aharonov-Bohm effect in quantum field theory: the fermionic vacuum attains nontrivial quantum numbers in the background of a magnetic vortex even in the case when the spatial region of nonvanishing external field strength is excluded. The dependence of the vacuum quantum numbers on the value of the vortex flux and the choice of the condition on the boundary of the excluded region is determined.
Quantum theory a two-time success story
Struppa, Daniele C
2013-01-01
Yakir Aharonov is one of the leading figures in the foundations of quantum physics. His contributions range from the celebrated Aharonov-Bohm effect (1959), to the more recent theory of weak measurements (whose experimental confirmations were recently ranked as the two most important results of physics in 2011). This volume will contain 27 original articles, contributed by the most important names in quantum physics, in honor of Aharonov's 80-th birthday.Sections include 'Quantum mechanics and reality,' with contributions from Nobel Laureates David Gross and Sir Anthony Leggett and Yakir Aharo
Energy Technology Data Exchange (ETDEWEB)
Smirnov, A. G., E-mail: smirnov@lpi.ru [I. E. Tamm Theory Department, P. N. Lebedev Physical Institute, Leninsky Prospect 53, Moscow 119991 (Russian Federation)
2015-12-15
We develop a general technique for finding self-adjoint extensions of a symmetric operator that respects a given set of its symmetries. Problems of this type naturally arise when considering two- and three-dimensional Schrödinger operators with singular potentials. The approach is based on constructing a unitary transformation diagonalizing the symmetries and reducing the initial operator to the direct integral of a suitable family of partial operators. We prove that symmetry preserving self-adjoint extensions of the initial operator are in a one-to-one correspondence with measurable families of self-adjoint extensions of partial operators obtained by reduction. The general scheme is applied to the three-dimensional Aharonov-Bohm Hamiltonian describing the electron in the magnetic field of an infinitely thin solenoid. We construct all self-adjoint extensions of this Hamiltonian, invariant under translations along the solenoid and rotations around it, and explicitly find their eigenfunction expansions.
International Nuclear Information System (INIS)
We develop a general technique for finding self-adjoint extensions of a symmetric operator that respects a given set of its symmetries. Problems of this type naturally arise when considering two- and three-dimensional Schrödinger operators with singular potentials. The approach is based on constructing a unitary transformation diagonalizing the symmetries and reducing the initial operator to the direct integral of a suitable family of partial operators. We prove that symmetry preserving self-adjoint extensions of the initial operator are in a one-to-one correspondence with measurable families of self-adjoint extensions of partial operators obtained by reduction. The general scheme is applied to the three-dimensional Aharonov-Bohm Hamiltonian describing the electron in the magnetic field of an infinitely thin solenoid. We construct all self-adjoint extensions of this Hamiltonian, invariant under translations along the solenoid and rotations around it, and explicitly find their eigenfunction expansions
Spin accumulation in a double-quantum-dot Aharonov–Bohm interferometer induced by Fano–Rashba effect
Energy Technology Data Exchange (ETDEWEB)
Wu, Haina [College of Sciences, Northeastern University, Shenyang 110819 (China); Han, Yu [Department of Physics, Liaoning University, Shenyang 110036 (China); Wang, Yan [College of Sciences, Northeastern University, Shenyang 110819 (China); Gong, Wei-Jiang, E-mail: gwjneu@163.com [College of Sciences, Northeastern University, Shenyang 110819 (China)
2013-06-15
Motivated by the results in the previous work (Phys. Rev. B 73, 235301), we investigate the nonequilibrium spin accumulation in a double-quantum-dot Aharonov–Bohm interferometer, by considering a local Rashba interaction in this structure. It is found that the spin accumulation is determined by the nonresonant transmission and Rashba interaction. Namely, the Fano–Rashba effect is a necessary condition to achieve the spin accumulation in the quantum dot of the resonant channel. Furthermore, the spin accumulation can be adjusted by the shift of the level of the nonresonant-channel quantum dot. When the intradot Coulomb interactions are taken into account within the Hubbard-I approximation, the spin accumulation is fully manipulated.
International Nuclear Information System (INIS)
The formulation of noncommutative quantum mechanics as a quantum system represented in the space of Hilbert–Schmidt operators is used to systematically derive, using the standard time slicing procedure, the path integral action for a particle moving in the noncommutative plane and in the presence of a magnetic field and an arbitrary potential. Using this action, the equation of motion and the ground state energy for the particle are obtained explicitly. The Aharonov–Bohm phase is derived using a variety of methods and several dualities between this system and other commutative and noncommutative systems are demonstrated. Finally, the equivalence of the path integral formulation with the noncommutative Schrödinger equation is also established. (paper)
Bruno, Patrick
2012-06-15
The (Berry-Aharonov-Anandan) geometric phase acquired during a cyclic quantum evolution of finite-dimensional quantum systems is studied. It is shown that a pure quantum state in a (2J+1)-dimensional Hilbert space (or, equivalently, of a spin-J system) can be mapped onto the partition function of a gas of independent Dirac strings moving on a sphere and subject to the Coulomb repulsion of 2J fixed test charges (the Majorana stars) characterizing the quantum state. The geometric phase may be viewed as the Aharonov-Bohm phase acquired by the Majorana stars as they move through the gas of Dirac strings. Expressions for the geometric connection and curvature, for the metric tensor, as well as for the multipole moments (dipole, quadrupole, etc.), are given in terms of the Majorana stars. Finally, the geometric formulation of the quantum dynamics is presented and its application to systems with exotic ordering such as spin nematics is outlined. PMID:23004240
Wang, Xiaofei; Liu, Xiaojie; Zhao, Xueyang; Yin, Haitao; Wan, Weilong; Feng, Li
2014-03-01
The spin polarized transport properties through an Aharonov-Bohm ring embedded with a double quantum dot-molecule in each arm with Rashba spin-orbit (RSO) interaction is theoretically studied in the framework of the equation of motion of Green's function. Based on molecular state representation, the anti-resonance phenomenon in the conductance spectrum is readily explained. We found that the position of antiresonant peaks in conductance spectrum is determined by the interdot coupling strengths. Moreover, the magnitude of conductance of each spin component can be manipulated by the Rashba spin orbit interaction strength. Especially only one spin component electron can be allowed to transport through this structure by modulating the strength of RSO interaction properly. PMID:24745284
Khatua, Pradip; Bansal, Bhavtosh; Shahar, Dan
2014-01-10
In a "thought experiment," now a classic in physics pedagogy, Feynman visualizes Young's double-slit interference experiment with electrons in magnetic field. He shows that the addition of an Aharonov-Bohm phase is equivalent to shifting the zero-field wave interference pattern by an angle expected from the Lorentz force calculation for classical particles. We have performed this experiment with one slit, instead of two, where ballistic electrons within two-dimensional electron gas diffract through a small orifice formed by a quantum point contact (QPC). As the QPC width is comparable to the electron wavelength, the observed intensity profile is further modulated by the transverse waveguide modes present at the injector QPC. Our experiments open the way to realizing diffraction-based ideas in mesoscopic physics. PMID:24483873
Energy Technology Data Exchange (ETDEWEB)
Ikhdair, Sameer M., E-mail: sikhdair@neu.edu.tr [Physics Department, Near East University, 922022 Nicosia, North Cyprus (Turkey); Hamzavi, Majid, E-mail: majid.hamzavi@gmail.com [Department of Basic Sciences, Shahrood Branch, Islamic Azad University, Shahrood (Iran, Islamic Republic of)
2012-11-01
Using the Nikiforov-Uvarov (NU) method, the energy levels and the wave functions of an electron confined in a two-dimensional (2D) pseudoharmonic quantum dot are calculated under the influence of temperature and an external magnetic field inside dot and Aharonov-Bohm (AB) field inside a pseudodot. The exact solutions for energy eigenvalues and wave functions are computed as functions of the chemical potential parameters, applied magnetic field strength, AB flux field, magnetic quantum number and temperature. Analytical expression for the light interband absorption coefficient and absorption threshold frequency are found as functions of applied magnetic field and geometrical size of quantum pseudodot. The temperature dependence energy levels for GaAs semiconductor are also calculated.
Bulgakov, Evgeny N; Sadreev, Almas F
2016-07-01
We consider the trapping of electrons with a definite spin polarization by bound states in the continuum (BSC) in the open Aharonov-Bohm rings in the presence of the Rashba spin-orbit interaction (RSOI). Neglecting the Zeeman term we show the existence of BSCs in the one-dimensional ring when the eigenstates of the closed ring are doubly degenerate. With account of the Zeeman term BSCs occur only at the points of threefold degeneracy. The BSCs are found in the parametric space of flux and RSOI strength in close pairs with opposite spin polarization. Thereby the spin polarization of electrons transmitted through the ring can be altered by minor variation of magnetic or electric field at the vicinity of these pairs. Numerical simulations of the two-dimensional open ring show similar results for the BSCs. Encircling the BSC points in the parametric space of the flux and the RSOI constant gives rise to a geometric phase. PMID:27165662
Ren, S L; Heremans, J J; Gaspe, C K; Vijeyaragunathan, S; Mishima, T D; Santos, M B
2013-10-30
Low-temperature Aharonov-Bohm oscillations in the magnetoresistance of mesoscopic interferometric rings patterned on an InGaAs/InAlAs heterostructure are investigated for their dependence on excitation current and temperature. The rings have an average radius of 650 nm, and a lithographic arm width of 300 nm, yielding pronounced interference oscillations over a wide range of magnetic fields. Apart from a current and temperature dependence, the oscillation amplitude also shows a quasi-periodic modulation with applied magnetic field. The phase coherence length is extracted by analysis of the fundamental and higher Fourier components of the oscillations, and by direct analysis of the amplitude and its dependence on parameters. It is concluded that the Thouless energy forms the measure of excitation energies for quantum decoherence. The amplitude modulation finds an explanation in the effect of the magnetic flux threading the finite width of the interferometer arms. PMID:24096892
Hou, Dong; Wang, Shikuan; Wang, Rulin; Ye, LvZhou; Xu, RuiXue; Zheng, Xiao; Yan, YiJing
2015-03-14
Several recent advancements for the hierarchical equations of motion (HEOM) approach are reported. First, we propose an a priori estimate for the optimal number of basis functions for the reservoir memory decomposition. Second, we make use of the sparsity of auxiliary density operators (ADOs) and propose two ansatzs to screen out all the intrinsic zero ADO elements. Third, we propose a new truncation scheme by utilizing the time derivatives of higher-tier ADOs. These novel techniques greatly reduce the memory cost of the HEOM approach, and thus enhance its efficiency and applicability. The improved HEOM approach is applied to simulate the coherent dynamics of Aharonov-Bohm double quantum dot interferometers. Quantitatively accurate dynamics is obtained for both noninteracting and interacting quantum dots. The crucial role of the quantum phase for the magnitude of quantum coherence and quantum entanglement is revealed. PMID:25770531
Gangopadhyay, Sunandan
2014-01-01
The formulation of noncommutative quantum mechanics as a quantum system represented in the space of Hilbert-Schmidt operators is used to systematically derive, using the standard time slicing procedure, the path integral action for a particle moving in the noncommutative plane and in the presence of a magnetic field and an arbitrary potential. Using this action, the equation of motion and the energy spectrum for the partcle are obtained explicitly. The Aharonov-Bohm phase is derived using a variety of methods and several dualities between this system and other commutative and noncommutative systems are demonstrated. Finally, the equivalence of the path integral formulation with the noncommutative Schr\\"{o}dinger equation is also established.
International Nuclear Information System (INIS)
Low-temperature Aharonov–Bohm oscillations in the magnetoresistance of mesoscopic interferometric rings patterned on an InGaAs/InAlAs heterostructure are investigated for their dependence on excitation current and temperature. The rings have an average radius of 650 nm, and a lithographic arm width of 300 nm, yielding pronounced interference oscillations over a wide range of magnetic fields. Apart from a current and temperature dependence, the oscillation amplitude also shows a quasi-periodic modulation with applied magnetic field. The phase coherence length is extracted by analysis of the fundamental and higher Fourier components of the oscillations, and by direct analysis of the amplitude and its dependence on parameters. It is concluded that the Thouless energy forms the measure of excitation energies for quantum decoherence. The amplitude modulation finds an explanation in the effect of the magnetic flux threading the finite width of the interferometer arms. (paper)
Spin accumulation in a double-quantum-dot Aharonov–Bohm interferometer induced by Fano–Rashba effect
International Nuclear Information System (INIS)
Motivated by the results in the previous work (Phys. Rev. B 73, 235301), we investigate the nonequilibrium spin accumulation in a double-quantum-dot Aharonov–Bohm interferometer, by considering a local Rashba interaction in this structure. It is found that the spin accumulation is determined by the nonresonant transmission and Rashba interaction. Namely, the Fano–Rashba effect is a necessary condition to achieve the spin accumulation in the quantum dot of the resonant channel. Furthermore, the spin accumulation can be adjusted by the shift of the level of the nonresonant-channel quantum dot. When the intradot Coulomb interactions are taken into account within the Hubbard-I approximation, the spin accumulation is fully manipulated
Smirnov, A. G.
2015-12-01
We develop a general technique for finding self-adjoint extensions of a symmetric operator that respects a given set of its symmetries. Problems of this type naturally arise when considering two- and three-dimensional Schrödinger operators with singular potentials. The approach is based on constructing a unitary transformation diagonalizing the symmetries and reducing the initial operator to the direct integral of a suitable family of partial operators. We prove that symmetry preserving self-adjoint extensions of the initial operator are in a one-to-one correspondence with measurable families of self-adjoint extensions of partial operators obtained by reduction. The general scheme is applied to the three-dimensional Aharonov-Bohm Hamiltonian describing the electron in the magnetic field of an infinitely thin solenoid. We construct all self-adjoint extensions of this Hamiltonian, invariant under translations along the solenoid and rotations around it, and explicitly find their eigenfunction expansions.
Quantum motion of a point particle in the presence of the Aharonov-Bohm potential in curved space
Silva, Edilberto O.; Ulhoa, Sérgio C.; Andrade, Fabiano M.; Filgueiras, Cleverson; Amorim, R. G. G.
2015-11-01
The nonrelativistic quantum dynamics of a spinless charged particle in the presence of the Aharonov-Bohm potential in curved space is considered. We chose the surface as being a cone defined by a line element in polar coordinates. The geometry of this line element establishes that the motion of the particle can occur on the surface of a cone or an anti-cone. As a consequence of the nontrivial topology of the cone and also because of two-dimensional confinement, the geometric potential should be taken into account. At first, we establish the conditions for the particle describing a circular path in such a context. Because of the presence of the geometric potential, which contains a singular term, we use the self-adjoint extension method in order to describe the dynamics in all space including the singularity. Expressions are obtained for the bound state energies and wave functions.
Roshanzamir-Nikou, M.; Goudarzi, H.
2016-02-01
A strong magnetic field significantly affects the intrinsic magnetic moment of fermions. In quantum electrodynamics, it was shown that the anomalous magnetic moment of an electron arises kinematically, while it results from a dynamical interaction with an external magnetic field for hadrons (proton). Taking the anomalous magnetic moment of a fermion into account, we find an exact expression for the boundstate energy and the corresponding eigenfunctions of a two-dimensional nonrelativistic spin-1/2 harmonic oscillator with a centripetal barrier (known as the isotonic oscillator) including an Aharonov-Bohm term in the presence of a strong magnetic field. We use the Laplace transform method in the calculations. We find that the singular solution contributes to the phase of the wave function at the origin and the phase depends on the spin and magnetic flux.
Khatua, Pradip; Bansal, Bhavtosh; Shahar, Dan
2014-01-01
In a "thought experiment," now a classic in physics pedagogy, Feynman visualizes Young's double-slit interference experiment with electrons in magnetic field. He shows that the addition of an Aharonov-Bohm phase is equivalent to shifting the zero-field wave interference pattern by an angle expected from the Lorentz force calculation for classical particles. We have performed this experiment with one slit, instead of two, where ballistic electrons within two-dimensional electron gas diffract through a small orifice formed by a quantum point contact (QPC). As the QPC width is comparable to the electron wavelength, the observed intensity profile is further modulated by the transverse waveguide modes present at the injector QPC. Our experiments open the way to realizing diffraction-based ideas in mesoscopic physics.
International Nuclear Information System (INIS)
The generalized form of Killingbeck potential is an attractive Coulomb term plus a linear term and a harmonic oscillator term, i.e. −a/r + br + λr2, which has a useful application in quarkonium spectroscopy. The ground state energy with the corresponding wave function are obtained for any arbitrary m-state in two-dimensional Klein–Gordon equation with equal mixture of scalar–vector Killingbeck potentials in the presence of constant magnetic and singular Ahoronov–Bohm flux fields perpendicular to the plane where the interacting charged particle is confined. The analytical exact iteration method is used in our solution. We obtain the energy eigensolutions for particle and antiparticle corresponding to S(r) = V(r) and S(r) = −V(r) cases, respectively. Some special cases like the Coulomb, harmonic oscillator potentials and the nonrelativistic limits are found in presence and absence of external fields. (author)
Directory of Open Access Journals (Sweden)
Sameer M. Ikhdair
2014-10-01
Full Text Available The two-dimensional solution of the spinless Klein–Gordon (KG equation for scalar–vector harmonic oscillator potentials with and without the presence of constant perpendicular magnetic and Aharonov–Bohm (AB flux fields is studied within the asymptotic function analysis and Nikiforov–Uvarov (NU method. The exact energy eigenvalues and normalized wave functions are analytically obtained in terms of potential parameters, magnetic field strength, AB flux field and magnetic quantum number. The results obtained by using different Larmor frequencies are compared with the results in the absence of both magnetic field (ωL = 0 and AB flux field (ξ = 0 case. Effects of external fields on the non-relativistic energy eigenvalues and wave functions solutions are also precisely presented.
Falaye, Babatunde James; Silva-Ortigoza, Ramón; Dong, Shi-Hai
2016-01-01
This study presents the confinement influences of Aharonov-Bohm-flux (AB-flux), electric and magnetic fields directed along $z$-axis and encircled by quantum plasmas, on the hydrogen atom. The all-inclusive effects result to a strongly attractive system while the localizations of quantum levels change and the eigenvalues decrease. We find that, the combined effect of the fields is stronger than solitary effect and consequently, there is a substantial shift in the bound state energy of the system. We also find that to perpetuate a low-energy medium for hydrogen atom in quantum plasmas, strong electric field and weak magnetic field are required, where AB-flux field can be used as a regulator. The application of perturbation technique utilized in this paper is not restricted to plasma physics, it can also be applied in molecular physics.
Fano effect in the Andreev reflection of the Aharonov-Bohm-Fano ring with Majorana bound states
Jiang, Cui; Zheng, Yi-Song
2015-06-01
The Andreev reflection in an Aharonov-Bohm-Fano ring induced by Majorana bound states (MBSs) is theoretically investigated. We find that compared with the Fano effect in the normal electron tunneling process, the Fano effect here is more determined by the structural parameters, i.e., the quantum dot level, the dot-MBS coupling, and the dot-MBS and MBS-lead couplings. By transforming the ring into its Nambu representation, we present a comprehensive analysis about the quantum interference in the Andreev reflection, and then explain the reason for the occurrence of the Fano effect. These results will be helpful for understanding the quantum interference in the MBS-assisted Andreev reflection.
Liu, Bin; Li, Yunyun; Zhou, Jun; Nakayama, Tsuneyoshi; Li, Baowen
2016-06-01
We theoretically investigate the spin-dependent Seebeck effect in an Aharonov-Bohm mesoscopic ring in the presence of both Rashba and Dresselhaus spin-orbit interactions under magnetic flux perpendicular to the ring. We apply the Green's function method to calculate the spin Seebeck coefficient employing the tight-binding Hamiltonian. It is found that the spin Seebeck coefficient is proportional to the slope of the energy-dependent transmission coefficients. We study the strong dependence of spin Seebeck coefficient on the Fermi energy, magnetic flux, strength of spin-orbit coupling, and temperature. Maximum spin Seebeck coefficients can be obtained when the strengths of Rashba and Dresselhaus spin-orbit couplings are slightly different. The spin Seebeck coefficient can be reduced by increasing temperature and disorder.
Energy Technology Data Exchange (ETDEWEB)
Hou, Dong; Xu, RuiXue; Zheng, Xiao, E-mail: xz58@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang, Shikuan [Department of Physics, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018 (China); Wang, Rulin [Beijing Computational Science Research Center, Beijing 100084 (China); Ye, LvZhou [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yan, YiJing, E-mail: yyan@ust.hk [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong (China)
2015-03-14
Several recent advancements for the hierarchical equations of motion (HEOM) approach are reported. First, we propose an a priori estimate for the optimal number of basis functions for the reservoir memory decomposition. Second, we make use of the sparsity of auxiliary density operators (ADOs) and propose two ansatzs to screen out all the intrinsic zero ADO elements. Third, we propose a new truncation scheme by utilizing the time derivatives of higher-tier ADOs. These novel techniques greatly reduce the memory cost of the HEOM approach, and thus enhance its efficiency and applicability. The improved HEOM approach is applied to simulate the coherent dynamics of Aharonov–Bohm double quantum dot interferometers. Quantitatively accurate dynamics is obtained for both noninteracting and interacting quantum dots. The crucial role of the quantum phase for the magnitude of quantum coherence and quantum entanglement is revealed.
Falaye, Babatunde James; Sun, Guo-Hua; Silva-Ortigoza, Ramón; Dong, Shi-Hai
2016-05-01
This study presents the confinement influences of Aharonov-Bohm (AB) flux and electric and magnetic fields directed along the z axis and encircled by quantum plasmas on the hydrogen atom. The all-inclusive effects result in a strongly attractive system while the localizations of quantum levels change and the eigenvalues decrease. We find that the combined effect of the fields is stronger than a solitary effect and consequently there is a substantial shift in the bound state energy of the system. We also find that to perpetuate a low-energy medium for the hydrogen atom in quantum plasmas, a strong electric field and weak magnetic field are required, whereas the AB flux field can be used as a regulator. The application of the perturbation technique utilized in this paper is not restricted to plasma physics; it can also be applied in molecular physics.
Indian Academy of Sciences (India)
A M Jayannavar
2002-02-01
We present a simple model of transmission across a metallic mesoscopic ring. In one of its arm an electron interacts with a single magnetic impurity via an exchange coupling. We show that entanglement between electron and spin impurity states leads to reduction of Aharonov–Bohm oscillations in the transmission coefﬁcient. The spin-conductance is asymmetric in the ﬂux reversal as opposed to the two-probe electrical conductance which is symmetric. In the same model, in contradiction to the naive expectation of a current magniﬁcation effect, we observe enhancement as well as suppression of this effect depending on the system parameters. The limitations of this model to the general notion of dephasing or decoherence in quantum systems are pointed out.
Molinari, Vincenzo
2014-01-01
He-4 is known to become superfluid at very low temperatures. This effect is now generally accepted to be connected with BEC (Bose-Einstein Condensation). The dispersion relation of pressure waves in superfluid He-4 has been determined at 1.1 {\\deg}K by Yarnell et al., and exhibits a non monotonic behaviour - with a maximum and a minimum - usually explained in terms of excitations called rotons, introduced by Landau. In the present work an attempt is made to describe the phenomenon within the bohmian interpretation of QM. To this end, the effects of the intermolecular potential, taken to be essentially of the Lennard-Jones type, are included as a Vlasov-type self-consistent field. A dispersion relation is found, that is in good agreement with Yarnell's curve. Keywords: Bohm potential; Intermolecular potential; Dispersion relation; Superfluid He-4; First sound. PACS: 05.30.Jp; 05.20.Dd; 03.75.Kk; 67.25.dt
International Nuclear Information System (INIS)
The second-order Zeeman effect of the sodium clock transition in a weak magnetic field of less than 50 μT was measured as the scalar Aharonov-Bohm phase by two-photon stimulated Raman atom interferometry. The ac Stark effect of the Raman pulse was canceled out by adopting an appropriate intensity ratio of two photons in the Raman pulse. The Ramsey fringes for the pulse separation of 7 ms were obtained with a phase uncertainty of π/200 rad. The nondispersive feature of the scalar Aharonov-Bohm phase was clearly demonstrated through 18 fringes with constant amplitude. The Breit-Rabi formula of the sodium clock transition was verified to be Δν=(0.222±0.003)x1012xB1.998±0.004 in a magnetic field of less than 50 μT.
Monisha, P. J.; Sankar, I. V.; Sil, Shreekantha; Chatterjee, Ashok
2016-02-01
Persistent current in a correlated quantum ring threaded by an Aharonov-Bohm flux is studied in the presence of electron-phonon interactions and Rashba spin-orbit coupling. The quantum ring is modeled by the Holstein-Hubbard-Rashba Hamiltonian and the energy is calculated by performing the conventional Lang-Firsov transformation followed by the diagonalization of the effective Hamiltonian within a mean-field approximation. The effects of Aharonov-Bohm flux, temperature, spin-orbit and electron-phonon interactions on the persistent current are investigated. It is shown that the electron-phonon interactions reduce the persistent current, while the Rashba coupling enhances it. It is also shown that temperature smoothens the persistent current curve. The effect of chemical potential on the persistent current is also studied.
International Nuclear Information System (INIS)
In the nonrelativistic case it has been found that whenever the relation mc2/e2 m) is satisfied, where α is a flux, gm is magnetic moment, and X(α,gm) is some function that is nonzero only for gm>2, then the matter is unstable against formation of the flux α. The result persists down to gm=2 provided the Aharonov-Bohm potential is supplemented with a short range attractive potential. The results are obtained by calculating the change of the density of states induced by the Aharonov-Bohm potential. The Krein-Friedel formula for this long-ranged potential is shown to be valid when supplemented with zeta function regularization. (author). 23 refs
Institute of Scientific and Technical Information of China (English)
高长军; 沈有根
2002-01-01
We present the classical solution of Lagrange equations for the Reissner-Nordstrom black hole with a global monopole in the background of de Sitter space-time. Then we obtain the wavefunction of the space-time by solving the Wheeler-De Witt equation. De Broglie-Bohm interpretation applied to the wavefunction gives the quantum solution of the space-time. Finally, the quantum effect on Hawking radiation is studied.
International Nuclear Information System (INIS)
The thermodynamic and spectral properties of a two-dimensional electron gas with an antidot in a strong magnetic field, rc≤r0, where rc is the cyclotron radius and r0 is the antidot effective radius, are studied via a solvable model with the antidot confinement potential U∼1/r2. The edge states localized at the antidot boundary result in an Aharonov-Bohm-type oscillatory dependence of the magnetization as a function of the magnetic field flux through the antidot. These oscillations are superimposed on the de Haas--van Alphen oscillations. In the strong-field limit, ℎωc∼εF, where ωc is the cyclotron frequency and εF is the Fermi energy, the amplitude of the Aharonov-Bohm-type oscillations of the magnetization due to the contribution of the lowest edge state is ∼μBkFrc (μB is the Bohr magneton and kF is the Fermi wave vector). When the magnetic field is decreased, higher edge states can contribute to the magnetization, leading to the appearance of a beating pattern in the Aharonov-Bohm oscillations. The role of temperature in suppressing the oscillatory contribution due to higher edge states is analyzed. Rapid oscillations of the magnetization as a function of the Aharonov-Bohm flux, occurring on a scale of a small fraction of the flux quantum hc/e, are demonstrated. The appearance of a manifold of non- equidistant frequencies in the magneto-optical-absorption spectrum, due to transitions between electronic edge states localized near the antidot boundary, is predicted
Moroz, Alexander
1995-01-01
Both the nonrelativistic scattering and the spectrum in the presence of the Aharonov-Bohm potential are analyzed. The single-particle density of states (DOS) for different self-adjoint extensions is calculated. The DOS provides a link between different physical quantities and is a natural starting point for their calculation. The consequences of an asymmetry of the S matrix for the generic self-adjoint extension are examined. I. Introduction II. Impenetrable flux tube and the density of state...
International Nuclear Information System (INIS)
This Letter deals with the effect of a delta-potential barrier on the one-dimensional and asymmetric Aharonov-Bohm ring with Rashba spin-orbit interaction. The analytic expressions of the transmission amplitude and conductance are derived by applying the transfer matrix method in the one-electron scattering formalism. Resorting to an adequate tuning of the Aharonov-Bohm magnetic flux and Rashba coupling strength, a control of the conductance can be done by varying the strength and the location of the barrier. This may be useful in the design of further mesoscopic spin filters by using suitable asymmetry configurations. -- Highlights: → An asymmetric Aharonov-Bohm ring with Rashba spin-orbit interaction is considered. → The effect of a delta-potential barrier on this ring is examined. → The analytic expression of the transmission amplitude is derived. → The conductance can be controlled by varying the barrier parameters. → The asymmetric ring can acts like a spin filter device.
Klein-Gordon Oscillator in Kaluza-Klein Theory
Carvalho, Josevi; Cavalcante, Everton; Furtado, Claudio
2016-01-01
In this contribution we study the Klein-Gordon oscillator on the curved background within the Kaluza-Klein theory. The problem of interaction between particles coupled harmonically with a topological defects in Kaluza-Klein theory is studied. We consider a series of topological defects, that treat the Klein-Gordon oscillator coupled to this background and find the energy levels and corresponding eigenfunctions in these cases. We show that the energy levels depend on the global parameters characterizing these spacetimes. We also investigate a quantum particle described by the Klein-Gordon oscillator interacting with a cosmic dislocation in Som-Raychaudhuri spacetime in the presence of homogeneous magnetic field in a Kaluza-Klein theory. In this case, the spectrum of energy is determined, and we observe that these energy levels are the sum of the term related with Aharonov-Bohm flux and of the parameter associated to the rotation of the spacetime.
Aharonov–Bohm rings with strong spin–orbit interaction: the role of sample-specific properties
International Nuclear Information System (INIS)
We present low-temperature transport experiments on Aharonov–Bohm (AB) rings fabricated from two-dimensional hole gases in p-type GaAs/AlGaAs heterostructures. Highly visible h/e (up to 15%) and h/2e oscillations, present for different gate voltages, prove the high quality of the fabricated devices. Like in previous work, a clear beating pattern of the h/e and h/2e oscillations is present in the magnetoresistance, producing split peaks in the Fourier spectrum. The magnetoresistance evolution is presented and discussed as a function of temperature and gate voltage. It is found that sample specific properties have a pronounced influence on the observed behaviour. For example, the interference of different transverse modes or the interplay between h/e oscillations and conductance fluctuations can produce the features mentioned above. In previous work they have occasionally been interpreted as signatures of spin–orbit interaction (SOI)-induced effects. In the light of these results, the unambiguous identification of SOI-induced phase effects in AB rings remains still an open and challenging experimental task. (paper)
Magnetic-field-tuned Aharonov-Bohm oscillations and evidence for non-Abelian anyons at ν = 5/2.
Willett, R L; Nayak, C; Shtengel, K; Pfeiffer, L N; West, K W
2013-11-01
We show that the resistance of the ν = 5/2 quantum Hall state, confined to an interferometer, oscillates with the magnetic field consistent with an Ising-type non-Abelian state. In three quantum Hall interferometers of different sizes, resistance oscillations at ν = 7/3 and integer filling factors have the magnetic field period expected if the number of quasiparticles contained within the interferometer changes so as to keep the area and the total charge within the interferometer constant. Under these conditions, an Abelian state such as the (3, 3, 1) state would show oscillations with the same period as at an integer quantum Hall state. However, in an Ising-type non-Abelian state there would be a rapid oscillation associated with the "even-odd effect" and a slower one associated with the accumulated Abelian phase due to both the Aharonov-Bohm effect and the Abelian part of the quasiparticle braiding statistics. Our measurements at ν = 5/2 are consistent with the latter. PMID:24237543
International Nuclear Information System (INIS)
Using non-equilibrium Green's functions' technology combined with small polaron transformation, we theoretically study the inelastic spin Seebeck effects in a controllable Aharonov–Bohm interferometer based on a degenerate molecular quantum dot level. The numerical results show that when the direct coupling between electrodes is switched on, the spin-dependent thermoelectric efficiency will be suppressed, but the magnetic flux can modulate the thermoelectric line-shapes regularly and the pure spin current generation can be achieved by the temperature gradient. When the direct coupling between electrodes is closed, the spin-dependent thermoelectric efficiency will be raised greatly and the heating resulting from the electron–phonon coupling can improve it effectively. - Highlights: • We develop a new numerical method to implement the calculation for inelastic Fano-resonance thermoelectric transport. • When the electrodes' direct coupling is open, the magnetic flux can modulate the line-shape of thermoelectric functions regularly. • The pure spin current generation can be achieved by the temperature gradient and the electrodes' direct coupling. • When the electrodes' coupling is closed, the spin-dependent thermoelectric efficiency will be raised greatly and the heating to the phonon bath can improve it effectively
Energy Technology Data Exchange (ETDEWEB)
Almeida, N. A.; Benilov, M. S. [Departamento de Fisica, CCCEE, Universidade da Madeira Largo do Municipio, 9000 Funchal (Portugal)
2012-07-15
A transformation of the ion momentum equation simplifies a mathematical description of the transition layer between a quasi-neutral plasma and a collisionless sheath and clearly reveals the physics involved. Balance of forces acting on the ion fluid is delicate in the vicinity of the sonic point and weak effects come into play. For this reason, the passage of the ion fluid through the sonic point, which occurs in the transition layer, is governed not only by inertia and electrostatic force but also by space charge and ion-atom collisions and/or ionization. Occurrence of different scenarios of asymptotic matching in the plasma-sheath transition is analyzed by means of simple mathematical examples, asymptotic estimates, and numerical calculations. In the case of a collisionless sheath, the ion speed distribution plotted on the logarithmic scale reveals a plateau in the intermediate region between the sheath and the presheath. The value corresponding to this plateau has the meaning of speed with which ions leave the presheath and enter the sheath; the Bohm speed. The plateau is pronounced reasonably well provided that the ratio of the Debye length to the ion mean free path is of the order of 10{sup -3} or smaller. There is no such plateau if the sheath is collisional and hence no sense in talking of a speed with which ions enter the sheath.
Institute of Scientific and Technical Information of China (English)
M. Maamache; C. Lahoulou; Y. Saadi
2009-01-01
Invariant operator method for discrete or continuous spectrum eigenvalue and unitary transformation approach are employed to study the two-dimensional time-dependent Pauli equation in presence of the Aharonov-Bohm effect (AB) and external scalar potential. For the spin particles the problem with the magnetic field is that it introduces a singularity into wave equation at the origin. A physical motivation is to replace the zero radius flux tube by one of radius R, with the additional condition that the magnetic field be confined to the surface of the tube, and then taking the limit R → 0 at the end of the computations. We point that the invariant operator must contain the step function θ(r - R). Consequently, the problem becomes more complicated. In order to avoid this difficulty, we replace the radius R by p(t)R, where p(t) is a positive time-dependent function. Then at the end of calculations we take the limit R →0.The qualitative properties for the invariant operator spectrum are described separately for the different values of the parameter C appearing in the nonlinear auxiliary equation satisfied by p(t), i.e., C > 0, C = 0, and C 0) or continuous (C≤0).
International Nuclear Information System (INIS)
Invariant operator method for discrete or continuous spectrum eigenvalue and unitary transformation approach are employed to study the two-dimensional time-dependent Pauli equation in presence of the Aharonov-Bohm effect (AB) and external scalar potential. For the spin particles the problem with the magnetic field is that it introduces a singularity into wave equation at the origin. A physical motivation is to replace the zero radius flux tube by one of radius R, with the additional condition that the magnetic field be confined to the surface of the tube, and then taking the limit R → 0 at the end of the computations. We point that the invariant operator must contain the step function θ(r - R). Consequently, the problem becomes more complicated. In order to avoid this difficulty, we replace the radius R by ρ(t)R, where ρ(t) is a positive time-dependent function. Then at the end of calculations we take the limit R → 0. The qualitative properties for the invariant operator spectrum are described separately for the different values of the parameter C appearing in the nonlinear auxiliary equation satisfied by ρ(t), i.e., C > 0, C = 0, and C 0) or continuous (C ≤ 0). (general)
Energy Technology Data Exchange (ETDEWEB)
Jiang, Feng, E-mail: fjiang@shiep.edu.cn [School of Mathematics and Physics, Shanghai University of Electric Power, Shanghai, 200090 (China); Shi, Changguang [School of Mathematics and Physics, Shanghai University of Electric Power, Shanghai, 200090 (China); Yan, Yonghong, E-mail: yhyan@fudan.edu.cn [Department of Physics, Shaoxing University, Shaoxing, 312000 (China); Xie, Hang [Department of Chemistry, The University of Hong Kong, Pofkulam Road, Hong Kong (China); Yan, Yijing [Department of Chemistry, Hong Kong University of Science and Technology, Kowloon, Hong Kong (China); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)
2015-02-20
Using non-equilibrium Green's functions' technology combined with small polaron transformation, we theoretically study the inelastic spin Seebeck effects in a controllable Aharonov–Bohm interferometer based on a degenerate molecular quantum dot level. The numerical results show that when the direct coupling between electrodes is switched on, the spin-dependent thermoelectric efficiency will be suppressed, but the magnetic flux can modulate the thermoelectric line-shapes regularly and the pure spin current generation can be achieved by the temperature gradient. When the direct coupling between electrodes is closed, the spin-dependent thermoelectric efficiency will be raised greatly and the heating resulting from the electron–phonon coupling can improve it effectively. - Highlights: • We develop a new numerical method to implement the calculation for inelastic Fano-resonance thermoelectric transport. • When the electrodes' direct coupling is open, the magnetic flux can modulate the line-shape of thermoelectric functions regularly. • The pure spin current generation can be achieved by the temperature gradient and the electrodes' direct coupling. • When the electrodes' coupling is closed, the spin-dependent thermoelectric efficiency will be raised greatly and the heating to the phonon bath can improve it effectively.
Spin power and efficiency in an Aharnov-Bohm ring with an embedded magnetic impurity quantum dot
Energy Technology Data Exchange (ETDEWEB)
Yang, Xi; Guo, Yong, E-mail: guoy66@tsinghua.edu.cn [Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center of Quantum Matter, Beijing (China); Zheng, Jun [College of New Energy, Bohai University, Jinzhou 121013 (China); Chi, Feng [School of Physical Science and Technology, Inner Mongolia University, Huhehaote 010023 (China)
2015-05-11
Spin thermoelectric effects in an Aharnov-Bohm ring with a magnetic impurity quantum dot (QD) are theoretically investigated by using the nonequilibrium Green's function method. It is found that due to the exchange coupling between the impurity and the electrons in QD, spin output power, and efficiency can be significant and be further modulated by the gate voltage. The spin thermoelectric effect can be modulated effectively by adjusting the Rashba spin-orbit interaction (RSOI) and the magnetic flux. The spin power and efficiency show zigzag oscillations, and thus spin thermoelectric effect can be switched by adjusting the magnetic flux phase factor and RSOI ones. In addition, the spin efficiency can be significantly enhanced by the coexistence of the RSOI and the magnetic flux, and the maximal value of normalized spin efficiency η{sub max}/η{sub C} = 0.35 is obtained. Our results show that such a QD ring device may be used as a manipulative spin thermoelectric generator.
The persistent current in an Aharonov-Bohm ring with a side-coupled quantum dot
Institute of Scientific and Technical Information of China (English)
Zhou Bo; Wu Shao-Quan; Sun Wei-Li; Zhou Xiao-Lin
2004-01-01
We have investigated the persistent current in a mesoscopic ring with a side-coupled quantum dot. The problems are probed by using the one-impurity Anderson Hamiltonian and are treated with the slave boson mean field theory. It is shown that the persistent current in this system has the spin fluctuations, and the charge transfers between the two subsystems are suppressed in the limit of △/TKo < 1. The minimum value of the persistent current for ζK/L = 5 of the odd parity system provides an opportunity to detect the Kondo screening cloud.
Effect of the Aharonov - Bohm Flux on the Magnetic Gap Soliton%一维铁磁链中的磁隙孤子激发
Institute of Scientific and Technical Information of China (English)
许长谭
2001-01-01
采用Holstein-Primakoff变换、相干态表示、含时微扰原理和多重标度方法,研究了Aharonov-Bohm(A-B)磁通对一维铁磁链中的磁隙孤子产生的影响,得到了在A-B磁通影响下的磁隙孤子的峰值、宽度、能量和自旋空间排列.
Spin transistor action from Onsager reciprocity and SU(2) gauge theory
Adagideli, Inanc
2012-02-01
We construct a local gauge transformation to show how a generic, nonhomogeneous SU(2) spin-orbit Hamiltonian reduces to two U(1) Hamiltonians for spinless fermions at opposite magnetic fields, to leading order in the spin-orbit strength. Using an Onsager reciprocity relation, we show how the resulting spin conductance vanishes in a two-terminal setup, and how it is turned on by either weakly breaking time-reversal symmetry by applied magnetic fields or opening additional transport terminals. We numerically illustrate our theory for diffusive conductors, ballistic mesoscopic cavities as well as Aharonov-Bohm rings.
Hu, Huping; Wu, Maoxin
2004-01-01
A novel theory of consciousness is proposed in this paper. We postulate that consciousness is intrinsically connected to quantum spin since the latter is the origin of quantum effects in both Bohm and Hestenes quantum formulism and a fundamental quantum process associated with the structure of space-time. That is, spin is the “mind-pixel.” The unity of mind is achieved by entanglement of the mind-pixels. Applying these ideas to the particular structures and dynamics of the brain, we theorize ...
Spin transistor action from Onsager reciprocity and SU(2) gauge theory
International Nuclear Information System (INIS)
We construct a local gauge transformation to show how, in confined systems, a generic, weak non-homogeneous SU(2) spin-orbit Hamiltonian reduces to two U(1) Hamiltonians for spinless fermions at opposite magnetic fields, to leading order in the spin-orbit strength. Using an Onsager relation, we further show how the resulting spin conductance vanishes in a two-terminal setup, and how it is turned on by either weakly breaking time-reversal symmetry or opening additional transport terminals. We numerically check our theory for mesoscopic cavities as well as Aharonov-Bohm rings.