Submit to Symmetry Review for Symmetry Propose a Special Issue

Journal Menu

Journal Browser

► Journal Browser

Special Issue "Quantum Dynamics in Josephson Junctions and Symmetry"

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Published Papers

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Physics".

Deadline for manuscript submissions: closed (30 April 2023) | Viewed by 10698

Share This Special Issue

Special Issue Editor

Prof. Nikolay Klenov

E-Mail Website
Guest Editor

Physics Department, Lomonosov Moscow State University, 119991 Moscow, Russia
Interests: Josephson systems; quantum computations; superconducting spintronics; artificial neural networks; quantum optics; physics of plasmas
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

A programmable quantum computer based on superconducting technologies has already demonstrated supremacy over the most powerful supercomputers in the world when solving a specially developed test problem. Existing quantum processors on Josephson junctions differ in the number and type of qubits, the number of interqubit connections, and their physical implementation. From the outside, such computers resemble a complex quantum system with sophisticated techniques for state control and read-out. This allows Quantum Dynamics in Josephson Junction Systems to be used for analyzing solutions to a number of problems from a wide variety of fields, including molecular chemistry, biology, periodic and quasiperiodic crystals, and pattern recognition. On the other hand, the accumulated methods of applying the "laws of symmetry" to physics, chemistry, biology, mathematics, and computer science can be used to improve Josephson quantum computers. These two mutually complementary features inspired us to start working on this multidisciplinary Special Issue of the Symmetry journal.

Prof. Nikolay Klenov
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Symmetry is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Josephson qubits
Josephson neural networks
Quantum supremacy
Quantum simulations
Quantum operations

Published Papers (6 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

Jump to: Review

10 pages, 4739 KiB

Open AccessArticle

Controlling I-V Hysteresis in Al/Pt Bilayer Symmetric SQUIDs at Millikelvin Temperatures

and

Symmetry 2023, 15(2), 550; https://doi.org/10.3390/sym15020550 - 18 Feb 2023

Viewed by 1314

Abstract

We study operation of a superconducting quantum interference devices (SQUIDs) based on a new bilayer material. They can be used for the ultra-sensitive detection of magnetic momentum at temperatures down to milliKelvin range. Typically, thermal origin hysteresis of the symmetric SQUID current-voltage curves [...] Read more.

T > 0.6 T c

. We used a new bilayer material for SQUID fabrication, namely proximity-coupled superconductor/normal-metal (S/N) bilayers (aluminum 25 nm/platinum 5 nm). Because of the 5 nm Pt-layer, Al/Pt devices show nonhysteretic behavior in a broad temperature range from 20 mK to 0.8 K. Furthermore, the Al/Pt bilayer devices demonstrate an order of magnitude lower critical current compared to the Al devices, which decreases the screening parameter (

β_{L}

) and improves the modulation depth of the critical current by magnetic flux. Operation at lower temperatures reduces thermal noise and increases the SQUID magnetic field resolution. Moreover, we expect strong decrease of two-level fluctuators on the surface of aluminum due to Pt-layer oxidation protection and hence significant reduction of the 1/f noise. Optimized geometry of Al/Pt symmetric SQUIDs is promising for the detection of single-electron spin flip. Full article

(This article belongs to the Special Issue Quantum Dynamics in Josephson Junctions and Symmetry)

► Show Figures

Graphical abstract

12 pages, 2201 KiB

Open AccessFeature PaperArticle

Peculiarities of Electron Wave Packet Dynamics in Planar Nanostructures in the Presence of Magnetic and Electric Fields

Darya Starodubtseva

and

Olga Tikhonova

Symmetry 2022, 14(10), 2215; https://doi.org/10.3390/sym14102215 - 20 Oct 2022

Viewed by 1022

Abstract

Currently, spatially localized electron densities and currents are considered to be candidates for use in the encoding of quantum information. For this reason, the control of their temporal dynamics is an important task. In this work, the spatiotemporal evolution of an electron wave packet in planar nanostructure in the presence of transverse magnetic and lateral electric fields is investigated by direct analytical solution of the non-stationary Schrödinger equation. Methods to control and manage the dynamics of the spatially localized electron density distribution are developed. The production of photon-like quantum states of electrons opens up opportunities for applications similar to quantum optical and quantum information technologies but implemented with charge carriers. Quantum control of the trajectory of the electron wave packet, accompanied by dramatic suppression of its spreading, is demonstrated. This study discovered methods to manage spatially localized electron behavior in a nanostructure that allows a controllable charge quantum transfer and gives rise to new prospects for quantum nanoelectronics technology. Full article

(This article belongs to the Special Issue Quantum Dynamics in Josephson Junctions and Symmetry)

► Show Figures

Figure 1

10 pages, 8317 KiB

Open AccessArticle

Superconductivity in Hierarchical 3D Nanostructured Pb–In Alloys

and

Symmetry 2022, 14(10), 2142; https://doi.org/10.3390/sym14102142 - 13 Oct 2022

Viewed by 1223

Abstract

The superconducting properties of hierarchical nanostructured samples of Pb–In alloys have been studied by the measurement of dynamic susceptibility

χ (T)

temperature dependence. Symmetric samples with different shapes and sizes were formed on a brass metallic net by cathode-metal electrodeposition with [...] Read more.

The superconducting properties of hierarchical nanostructured samples of Pb–In alloys have been studied by the measurement of dynamic susceptibility

χ (T)

temperature dependence. Symmetric samples with different shapes and sizes were formed on a brass metallic net by cathode-metal electrodeposition with a programmed pulsing current. Two different kinds of

χ (T)

dependence were observed in synthesized structures. The first kind was a broad superconductive transition without energy dissipation with a very weak response to the external magnetic field. The second kind was, conversely, an abrupt transition signifying an energy dissipation with a significant field response. This behavior depends on the ratio between a superconducting domain size (defined by the London penetration depth

λ

) and a crystallite size. In these cases, one or several superconducting domains are present in a sample. This result paves the way to controlling a superconducting domain size in materials with the parameters of a pulsed current. Full article

(This article belongs to the Special Issue Quantum Dynamics in Josephson Junctions and Symmetry)

► Show Figures

Figure 1

12 pages, 22266 KiB

Open AccessArticle

Dynamic Processes in a Superconducting Adiabatic Neuron with Non-Shunted Josephson Contacts

Marina Bastrakova

Anastasiya Gorchavkina

and

Symmetry 2021, 13(9), 1735; https://doi.org/10.3390/sym13091735 - 18 Sep 2021

Cited by 2 | Viewed by 2212

Abstract

We investigated the dynamic processes in a superconducting neuron based on Josephson contacts without resistive shunting (S_C-neuron). Such a cell is a key element of perceptron-type neural networks that operate in both classical and quantum modes. The analysis of the obtained results allowed us to find the mode when the transfer characteristic of the element implements the “sigmoid” activation function. The numerical approach to the analysis of the equations of motion and the Monte Carlo method revealed the influence of inertia (capacitances), dissipation, and temperature on the dynamic characteristics of the neuron. Full article

(This article belongs to the Special Issue Quantum Dynamics in Josephson Junctions and Symmetry)

► Show Figures

Figure 1

Review

Jump to: Research

32 pages, 14202 KiB

Open AccessFeature PaperReview

A Survey on Symmetrical Neural Network Architectures and Applications

and

Symmetry 2022, 14(7), 1391; https://doi.org/10.3390/sym14071391 - 06 Jul 2022

Cited by 9 | Viewed by 2256

Abstract

A number of modern techniques for neural network training and recognition enhancement are based on their structures’ symmetry. Such approaches demonstrate impressive results, both for recognition practice, and for understanding of data transformation processes in various feature spaces. This survey examines symmetrical neural network architectures—Siamese and triplet. Among a wide range of tasks having various mathematical formulation areas, especially effective applications of symmetrical neural network architectures are revealed. We systematize and compare different architectures of symmetrical neural networks, identify genetic relationships between significant studies of different authors’ groups, and discuss opportunities to improve the element base of such neural networks. Our survey builds bridges between a large number of isolated studies with significant practical results in the considered area of knowledge, so that the presented survey acquires additional relevance. Full article

(This article belongs to the Special Issue Quantum Dynamics in Josephson Junctions and Symmetry)

► Show Figures

Figure 1

20 pages, 2528 KiB

Open AccessReview

Theoretical Basis of Quantum-Mechanical Modeling of Functional Nanostructures

and

Symmetry 2021, 13(5), 883; https://doi.org/10.3390/sym13050883 - 16 May 2021

Cited by 1 | Viewed by 2356

Abstract

The paper presents an analytical review of theoretical methods for modeling functional nanostructures. The main evolutionary changes in the approaches of quantum-mechanical modeling are described. The foundations of the first-principal theory are considered, including the stationery and time-dependent Schrödinger equations, wave functions, the form of writing energy operators, and the principles of solving equations. The idea and specifics of describing the motion and interaction of nuclei and electrons in the framework of the theory of the electron density functional are presented. Common approximations and approaches in the methods of quantum mechanics are presented, including the Born–Oppenheimer approximation, the Hartree–Fock approximation, the Thomas–Fermi theory, the Hohenberg–Kohn theorems, and the Kohn–Sham formalism. Various options for describing the exchange–correlation energy in the theory of the electron density functional are considered, such as the local density approximation, generalized and meta-generalized gradient approximations, and hybridization of the generalized gradient method. The development of methods of quantum mechanics to quantum molecular dynamics or the dynamics of Car–Parrinello is shown. The basic idea of combining classical molecular modeling with calculations of the electronic structure, which is reflected in the potentials of the embedded atom, is described. Full article

(This article belongs to the Special Issue Quantum Dynamics in Josephson Junctions and Symmetry)

► Show Figures

Journal Menu

Journal Browser

Special Issue "Quantum Dynamics in Josephson Junctions and Symmetry"

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (6 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI