Method of calculations for electron transport in multiterminal quantum systems based on real-space lattice models

2002 ◽  
Vol 66 (16) ◽  
Author(s):  
H. Q. Xu
Keyword(s):  
Electron Transport ◽  
Lattice Models ◽  
Real Space ◽  
Quantum Systems ◽  
Space Lattice

scholarly journals ZnSnN 2 in Real Space and k‐Space: Lattice Constants, Dislocation Density, and Optical Band Gap

2021 ◽  
pp. 2100015
Author(s):  
Vegard Skiftestad Olsen ◽  
Vetle Øversjøen ◽  
Daniela Gogova ◽  
Béla Pécz ◽  
Augustinas Galeckas ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Band Gap ◽  
Optical Band Gap ◽  
Real Space ◽  
Lattice Constants ◽  
Space Lattice

scholarly journals Local Spin and Open Quantum Systems: Clarifying Misconceptions, Unifying Approaches

2020 ◽  
Author(s):  
Angel Martín Pendás ◽  
Evelio Francisco
Keyword(s):  
Quantum Control ◽  
Open Systems ◽  
Open Quantum Systems ◽  
Real Space ◽  
Quantum Systems ◽  
Spin Coupling ◽  
Molecular Systems ◽  
Open Quantum ◽  
Local Spin

<p>We now show that Clark and Davidson local spins operators are perfectly defined subsystem operators if a fragment is taken as an <i>open quantum system</i> (OQS). Open systems have become essential in quantum control and quantum computation, but have not received much attention in Chemistry. We have already shown (<i>J. Chem. Theory Comput</i>. <b>2018</b>, <i>15</i>, 1079) how real space OQSs can be defined in molecular systems and how they offer new insights relating quantum mechanical entaglement and chemical bonding. The OQS account of local spin that we offer yields a rigorous, yet easily accessible way to rationalize local spin values. A fragment is found in a mixed state direct sum of sectors characterized by different number of electrons that occur with different probabilities. The local spin is then a weighted sum of otherwise standard <i>S</i>(<i>S</i>+1) values. With OQS glasses, it is obvious that atomic or fragment spins should not vanish. Our approach thus casts doubts on any procedure used to annihilate them, like those used by Mayer and coworkers. OQS local spins allow for a fruitful use of models. One can propose easily sector probabilities for localized, covalent, ionic, zwitterionic, etc. situations, and examine their ideal local spins. We have mapped all 2c-2e cases, and shown how to do that in general multielectron cases. The role of electron correlation is also studied by tuning the Hubbard U/t parameter for H chains. Correlation induced localization changes the spin-coupling patterns even qualitatively, and show how the limiting antiferromagnet arises.</p>

scholarly journals Charge-current correlation equalities for quantum systems far from equilibrium

2019 ◽  
Vol 6 (6) ◽  
Author(s):  
Dragi Karevski ◽  
Gunter Schütz
Keyword(s):  
Linear Response ◽  
Space Dimension ◽  
Lattice Models ◽  
Quantum Systems ◽  
Translation Invariance ◽  
Response Functions ◽  
Current Correlation ◽  
Far From Equilibrium ◽  
Conserved Currents ◽  
A Current

We prove that a recently derived correlation equality between conserved charges and their associated conserved currents for quantum systems far from equilibrium [O.A. Castro-Alvaredo, B. Doyon, and T. Yoshimura, Phys. Rev. X 6, 041065 (2016)], is valid under more general conditions than assumed so far. Similar correlation identities, which in generalized Gibbs ensembles give rise to a current symmetry somewhat reminiscent of the Onsager relations, turn out to hold also in the absence of translation invariance, for lattice models, and in any space dimension, and to imply a symmetry of the non-equilibrium linear response functions.

Electron Transport in Open Quantum Systems

1993 ◽  
pp. 271-282
Author(s):  
W. R. Frensley ◽  
C. Fernando ◽  
J. R. Hellums ◽  
S. Venkatanarasimhan
Keyword(s):  
Electron Transport ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Open Quantum

scholarly journals A Proof of the Bloch Theorem for Lattice Models

2019 ◽  
Vol 177 (4) ◽  
pp. 717-726 ◽  
Author(s):  
Haruki Watanabe
Keyword(s):  
Boundary Condition ◽  
Tight Binding ◽  
Lattice Models ◽  
Quantum Systems ◽  
Open Boundary ◽  
Current Operator ◽  
Open Boundary Condition ◽  
Expectation Value ◽  
Bloch Theorem ◽  
Large Quantum

Abstract The Bloch theorem is a powerful theorem stating that the expectation value of the U(1) current operator averaged over the entire space vanishes in large quantum systems. The theorem applies to the ground state and to the thermal equilibrium at a finite temperature, irrespective of the details of the Hamiltonian as far as all terms in the Hamiltonian are finite ranged. In this work we present a simple yet rigorous proof for general lattice models. For large but finite systems, we find that both the discussion and the conclusion are sensitive to the boundary condition one assumes: under the periodic boundary condition, one can only prove that the current expectation value is inversely proportional to the linear dimension of the system, while the current expectation value completely vanishes before taking the thermodynamic limit when the open boundary condition is imposed. We also provide simple tight-binding models that clarify the limitation of the theorem in dimensions higher than one.

Real-space calculations for electron transport properties of nanostructures

2011 ◽  
Vol 23 (39) ◽  
pp. 394203 ◽  
Author(s):  
Tomoya Ono ◽  
Shigeru Tsukamoto ◽  
Yoshiyuki Egami ◽  
Yoshitaka Fujimoto
Keyword(s):  
Electron Transport ◽  
Transport Properties ◽  
Real Space ◽  
Electron Transport Properties
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