Parallel Quantum Circuit in a Tunnel Junction

Namarvar, Omid Faizy; Dridi, Ghassen; Joachim, Christian

doi:10.1038/srep30198

Cited by 14 publications

(11 citation statements)

References 24 publications

(67 reference statements)

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“…To the large variety of systems and models described by quantum graphs belong, e.g., superconducting quantum circuits 19 , quantum circuits in tunnel junctions 20 , experimental setups to realize high-dimensional multipartite quantum states 21 , discrete-time quantum gravity models 22 and functional connectivity in preclinical Alzheimer’s disease 23 .…”

Section: Introductionmentioning

confidence: 99%

Investigation of the diagonal elements of the Wigner’s reaction matrix for networks with violated time reversal invariance

Ławniczak

Sirko

2019

Sci Rep

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The distributions of the diagonal elements of the Wigner’s reaction matrix for open systems with violated time reversal T invariance in the case of large absorption are for the first time experimentally studied. The Wigner’s reaction matrix links the properties of chaotic systems with the scattering processes in the asymptotic region. Microwave networks consisting of microwave circulators were used in the experiment to simulate quantum graphs with violated T invariance. The distributions of the diagonal elements of the reaction matrix were experimentally evaluated by measuring of the two-port scattering matrix . The violation of T invariance in the networks with large absorption was demonstrated by calculating the enhancement factor W of the matrix . Our experimental results are in very good agreement with the analytic ones attained for the Gaussian unitary ensemble in the random matrix theory. The obtained results suggest that the distributions P ( ʋ ) and P ( u ) of the imaginary and the real parts of the diagonal elements of the Wigner’s reaction matrix together with the enhancement factor W can be used as a powerful tool for identification of systems with violated T symmetry and quantification of their absorption.

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Section: Introductionmentioning

confidence: 99%

Investigation of the diagonal elements of the Wigner’s reaction matrix for networks with violated time reversal invariance

Ławniczak

Sirko

2019

Sci Rep

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“…However, it has been reported that in molecular circuits with separated parallel components, the circuit conductance could increase nonadditively due to constructive interference between the parallel paths. [ 27–31 ] Unconventional constructive QI was also predicted theoretically in single molecular electronics multi‐channels, [ 32,33 ] which has been confirmed by the experimental verdict that the conductance of quadrivial anchored molecular is about 5 times larger than that of the bidirectional one. [ 34 ] However, Hoffmann et.al indicated that the charge transport mechanism remains an open question as the electrons traveling through the multiple linkers, even though the coherent transport gives better agreement with the experimental results than that of incoherent.…”

Section: Introductionmentioning

confidence: 70%

Nonadditive Transport in Multi‐Channel Single‐Molecule Circuits

Chen

Zheng

Liu

et al. 2020

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As stated in the classic Kirchhoff's circuit laws, the total conductance of two parallel channels in an electronic circuit is the sum of the individual conductance. However, in molecular circuits, the quantum interference (QI) between the individual channels may lead to apparent invalidity of Kirchhoff's laws. Such an effect can be very significant in single‐molecule circuits consisting of partially overlapped multiple transport channels. Herein, an investigation on how the molecular circuit conductance correlates to the individual channels is conducted in the presence of QI. It is found that the conductance of multi‐channel circuit consisting of both constructive and destructive QI is significantly smaller than the addition of individual ones due to the interference between channels. In contrast, the circuit consisting of destructive QI channels exhibits an additive transport. These investigations provide a new cognition of transport mechanism and manipulation of transport in multi‐channel molecular circuits.

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“…Quantum graphs are the unions of vertices connected by one-dimensional quantum bounds 8 , 9 . The importance of quantum graphs stems from the fact that they can be used to describe a huge number of physical and mathematical systems and models, e.g., nanophotonic lasers on graphs 10 , superconducting quantum circuits 11 , entanglement in graph states 12 , 13 , experimental setups for high-dimensional multipartite quantum states 14 , quantum circuits in tunnel junctions 15 , and Weyl and non-Weyl quantum graphs and networks 16 .…”

Section: Introductionmentioning

confidence: 99%

Isoscattering strings of concatenating graphs and networks

Ławniczak

Sawicki

Białous

et al. 2021

Sci Rep

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We identify and investigate isoscattering strings of concatenating quantum graphs possessing n units and 2n infinite external leads. We give an insight into the principles of designing large graphs and networks for which the isoscattering properties are preserved for $$n \rightarrow \infty $$ n → ∞ . The theoretical predictions are confirmed experimentally using $$n=2$$ n = 2 units, four-leads microwave networks. In an experimental and mathematical approach our work goes beyond prior results by demonstrating that using a trace function one can address the unsettled until now problem of whether scattering properties of open complex graphs and networks with many external leads are uniquely connected to their shapes. The application of the trace function reduces the number of required entries to the $$2n \times 2n $$ 2 n × 2 n scattering matrices $${\hat{S}}$$ S ^ of the systems to 2n diagonal elements, while the old measures of isoscattering require all $$(2n)^2$$ ( 2 n ) 2 entries. The studied problem generalizes a famous question of Mark Kac “Can one hear the shape of a drum?”, originally posed in the case of isospectral dissipationless systems, to the case of infinite strings of open graphs and networks.

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Parallel Quantum Circuit in a Tunnel Junction

Cited by 14 publications

References 24 publications

Investigation of the diagonal elements of the Wigner’s reaction matrix for networks with violated time reversal invariance

Investigation of the diagonal elements of the Wigner’s reaction matrix for networks with violated time reversal invariance

Nonadditive Transport in Multi‐Channel Single‐Molecule Circuits

Isoscattering strings of concatenating graphs and networks

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