SPIN BALLISTIC TRANSPORT AND SPIN CURRENT OSCILLATIONS IN MESOSCOPIC LOOP STRUCTURES

In the paper a theory of quantum interference in a loop structure caused by spin coherent transport and the Larmor precession of the electron spin is presented. The 'spin ballistic' regime is supposed to occur when the phase relaxation length of the spin part of electron wave function is much greater than the phase relaxation length of the 'orbital' part. If magnetic fields in two arms of the structure are different, the spin part of the wave function acquires a phase shift due to spin precession around the field. If the structure length L is chosen to be [Formula: see text], It is possible to 'wash out' the quantum interference related to the phase coherence of the 'orbital part' of the wave function, retaining at the same time that related to the phase coherence of the spin part and to reveal the corresponding conductance oscillations. Different mechanisms of spin relaxation as well as their influence on the spin transport are considered. The quantum interference in the time-dependent magnetic field is also discussed and similarities between this effect and Josephson one, as well as their differences are considered.

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Ballistic transport and quantum interference in InSb nanowire devices

Chinese Physics B ◽

10.1088/1674-1056/26/2/027305 ◽

2017 ◽

Vol 26 (2) ◽

pp. 027305 ◽

Cited By ~ 4

Author(s):

Sen Li ◽

Guang-Yao Huang ◽

Jing-Kun Guo ◽

Ning Kang ◽

Philippe Caroff ◽

...

Keyword(s):

Quantum Interference ◽

Ballistic Transport

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Quantum Interference

The Conceptual Foundations of Quantum Mechanics ◽

10.1093/oso/9780198844686.003.0005 ◽

2019 ◽

pp. 66-88

Author(s):

Jeffrey A. Barrett

Keyword(s):

Hilbert Space ◽

Wave Function ◽

Quantum Mechanics ◽

Quantum Interference ◽

Standard Theory ◽

Quantum Decoherence ◽

Entangled States ◽

Quantum Mechanical ◽

Standard Formulation ◽

Complex Valued

Moving to more subtle experiments, we consider how the standard formulation of quantum mechanics predicts and explains interference phenomena. Tracking the conditions under which one observes interference phenomena leads to the notion of quantum decoherence. We see why one must sharply distinguish between collapse phenomena and decoherence phenomena on the standard formulation of quantum mechanics. While collapses explain determinate measurement records, environmental decoherence just produces more complex, entangled states where the physical systems involved lack ordinary physical properties. We characterize the quantum-mechanical wave function as both an element of a Hilbert space and a complex-valued function over a configuration space. We also discuss how the wave function is interpreted in the standard theory.

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Investigating Quantum Coherence by Negative Excursions of the Wigner Quasi-Distribution

Applied Sciences ◽

10.3390/app9071344 ◽

2019 ◽

Vol 9 (7) ◽

pp. 1344 ◽

Cited By ~ 2

Author(s):

Mauro Ballicchia ◽

David Ferry ◽

Mihail Nedjalkov ◽

Josef Weinbub

Keyword(s):

Wave Function ◽

Quantum Interference ◽

Quantum Coherence ◽

Quantum Communication ◽

Electron System ◽

Physical Problem ◽

Quantum Superposition ◽

Negative Part ◽

Initial Momentum ◽

The Past

Quantum information and quantum communication are both strongly based on concepts of quantum superposition and entanglement. Entanglement allows distinct bodies, that share a common origin or that have interacted in the past, to continue to be described by the same wave function until evolution is coherent. So, there is an equivalence between coherence and entanglement. In this paper, we show the relation between quantum coherence and quantum interference and the negative parts of the Wigner quasi-distribution, using the Wigner signed-particle formulation. A simple physical problem consisting of electrons in a nanowire interacting with the potential of a repulsive dopant placed in the center of it creates a quasi two-slit electron system that separates the wave function into two entangled branches. The analysis of the Wigner quasi-distribution of this problem establishes that its negative part is principally concentrated in the region after the dopant between the two entangled branches, maintaining the coherence between them. Moreover, quantum interference is shown in this region both in the positive and in the negative part of the Wigner function and is produced by the superposition of Wigner functions evaluated at points of the momentum space that are symmetric with respect to the initial momentum of the injected electrons.

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Phase coherence of RVB wave function

Zeitschrift für Physik B Condensed Matter ◽

10.1007/bf01312490 ◽

1988 ◽

Vol 71 (3) ◽

pp. 311-314 ◽

Cited By ~ 6

Author(s):

P. Lederer ◽

Y. Takahashi

Keyword(s):

Wave Function ◽

Phase Coherence

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Space-time from Collapse of the Wave-function

Zeitschrift für Naturforschung A ◽

10.1515/zna-2018-0477 ◽

2019 ◽

Vol 74 (2) ◽

pp. 147-152 ◽

Cited By ~ 3

Author(s):

Tejinder P. Singh

Keyword(s):

Hilbert Space ◽

Wave Function ◽

Quantum Theory ◽

Minkowski Space ◽

Time Scales ◽

Quantum Interference ◽

Quantum Dynamics ◽

Space Time ◽

Minkowski Space Time ◽

Macroscopic Objects

AbstractWe propose that space-time results from collapse of the wave function of macroscopic objects, in quantum dynamics. We first argue that there ought to exist a formulation of quantum theory which does not refer to classical time. We then propose such a formulation by invoking an operator Minkowski space-time on the Hilbert space. We suggest relativistic spontaneous localisation as the mechanism for recovering classical space-time from the underlying theory. Quantum interference in time could be one possible signature for operator time, and in fact may have been already observed in the laboratory, on attosecond time scales. A possible prediction of our work seems to be that interference in time will not be seen for ‘time slit’ separations significantly larger than 100 attosecond, if the ideas of operator time and relativistic spontaneous localisation are correct.

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