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Pashin DS, Bastrakova MV, Rybin DA, Soloviev II, Klenov NV, Schegolev AE. Optimisation Challenge for a Superconducting Adiabatic Neural Network That Implements XOR and OR Boolean Functions. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:854. [PMID: 38786810 PMCID: PMC11124324 DOI: 10.3390/nano14100854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/01/2024] [Accepted: 05/11/2024] [Indexed: 05/25/2024]
Abstract
In this article, we consider designs of simple analog artificial neural networks based on adiabatic Josephson cells with a sigmoid activation function. A new approach based on the gradient descent method is developed to adjust the circuit parameters, allowing efficient signal transmission between the network layers. The proposed solution is demonstrated on the example of a system that implements XOR and OR logical operations.
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Affiliation(s)
- Dmitrii S. Pashin
- Faculty of Physics, Lobachevsky State University of Nizhni Novgorod, 603022 Nizhny Novgorod, Russia
| | - Marina V. Bastrakova
- Faculty of Physics, Lobachevsky State University of Nizhni Novgorod, 603022 Nizhny Novgorod, Russia
- Russian Quantum Centre, 143025 Moscow, Russia
| | - Dmitrii A. Rybin
- Faculty of Physics, Lobachevsky State University of Nizhni Novgorod, 603022 Nizhny Novgorod, Russia
| | - Igor. I. Soloviev
- Russian Quantum Centre, 143025 Moscow, Russia
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991 Moscow, Russia;
- National University of Science and Technology MISIS, 119049 Moscow, Russia;
| | - Nikolay V. Klenov
- National University of Science and Technology MISIS, 119049 Moscow, Russia;
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Andrey E. Schegolev
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991 Moscow, Russia;
- Science Department, Moscow Technical University of Communication and Informatics (MTUCI), 111024 Moscow, Russia
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Neilo A, Bakurskiy S, Klenov N, Soloviev I, Kupriyanov M. Spin-Valve-Controlled Triggering of Superconductivity. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:245. [PMID: 38334516 PMCID: PMC11154576 DOI: 10.3390/nano14030245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/13/2024] [Accepted: 01/14/2024] [Indexed: 02/10/2024]
Abstract
We have studied the proximity effect in an SF1S1F2s superconducting spin valve consisting of a massive superconducting electrode (S) and a multilayer structure formed by thin ferromagnetic (F1,2) and superconducting (S1, s) layers. Within the framework of the Usadel equations, we have shown that changing the mutual orientation of the magnetization vectors of the F1,2 layers from parallel to antiparallel serves to trigger superconductivity in the outer thin s-film. We studied the changes in the pair potential in the outer s-film and found the regions of parameters with a significant spin-valve effect. The strongest effect occurs in the region of parameters where the pair-potential sign is changed in the parallel state. This feature reveals new ways to design devices with highly tunable inductance and critical current.
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Affiliation(s)
- Alexey Neilo
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow 119991, Russia; (A.N.); (S.B.); (M.K.)
- National University of Science and Technology MISIS, Moscow 119049, Russia;
| | - Sergey Bakurskiy
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow 119991, Russia; (A.N.); (S.B.); (M.K.)
- National University of Science and Technology MISIS, Moscow 119049, Russia;
| | - Nikolay Klenov
- National University of Science and Technology MISIS, Moscow 119049, Russia;
- Dukhov All-Russia Research Institute of Automatics, Moscow 101000, Russia
- Faculty of Physics, Moscow State University, Moscow 119991, Russia
| | - Igor Soloviev
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow 119991, Russia; (A.N.); (S.B.); (M.K.)
- National University of Science and Technology MISIS, Moscow 119049, Russia;
- Dukhov All-Russia Research Institute of Automatics, Moscow 101000, Russia
| | - Mikhail Kupriyanov
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow 119991, Russia; (A.N.); (S.B.); (M.K.)
- National University of Science and Technology MISIS, Moscow 119049, Russia;
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Pashin DS, Pikunov PV, Bastrakova MV, Schegolev AE, Klenov NV, Soloviev II. A bifunctional superconducting cell as flux qubit and neuron. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2023; 14:1116-1126. [PMID: 38034474 PMCID: PMC10682513 DOI: 10.3762/bjnano.14.92] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/01/2023] [Indexed: 12/02/2023]
Abstract
Josephson digital or analog ancillary circuits are an essential part of a large number of modern quantum processors. The natural candidate for the basis of tuning, coupling, and neromorphic co-processing elements for processors based on flux qubits is the adiabatic (reversible) superconducting logic cell. Using the simplest implementation of such a cell as an example, we have investigated the conditions under which it can optionally operate as an auxiliary qubit while maintaining its "classical" neural functionality. The performance and temperature regime estimates obtained confirm the possibility of practical use of a single-contact inductively shunted interferometer in a quantum mode in adjustment circuits for q-processors.
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Affiliation(s)
- Dmitrii S Pashin
- Faculty of Physics, Lobachevsky State University of Nizhni Novgorod, 603022 Nizhny Novgorod, Russia
| | - Pavel V Pikunov
- Faculty of Physics, Lobachevsky State University of Nizhni Novgorod, 603022 Nizhny Novgorod, Russia
| | - Marina V Bastrakova
- Faculty of Physics, Lobachevsky State University of Nizhni Novgorod, 603022 Nizhny Novgorod, Russia
- Russian Quantum Center, 143025 Skolkovo, Moscow, Russia
| | - Andrey E Schegolev
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
- Moscow Technical University of Communication and Informatics (MTUCI), 111024 Moscow, Russia
| | - Nikolay V Klenov
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
- National University of Science and Technology MISIS, 119049 Moscow, Russia
| | - Igor I Soloviev
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
- National University of Science and Technology MISIS, 119049 Moscow, Russia
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Karabassov T, Pashkovskaia VD, Parkhomenko NA, Guravova AV, Kazakova EA, Lvov BG, Golubov AA, Vasenko AS. Density of states in the presence of spin-dependent scattering in SF bilayers: a numerical and analytical approach. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2022; 13:1418-1431. [PMID: 36540701 PMCID: PMC9732889 DOI: 10.3762/bjnano.13.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 11/07/2022] [Indexed: 06/17/2023]
Abstract
We present a quantitative study of the density of states (DOS) in SF bilayers (where S is a bulk superconductor and F is a ferromagnetic metal) in the diffusive limit. We solve the quasiclassical Usadel equations in the structure considering the presence of magnetic and spin-orbit scattering. For practical reasons, we propose the analytical solution for the density of states in SF bilayers in the case of a thin ferromagnet and low transparency of the SF interface. This solution is confirmed by numerical calculations using a self-consistent two-step iterative method. The behavior of DOS dependencies on magnetic and spin-orbit scattering times is discussed.
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Affiliation(s)
| | | | | | | | - Elena A Kazakova
- Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | | | - Alexander A Golubov
- Faculty of Science and Technology and MESA Institute for Nanotechnology, University of Twente, 7500 AE Enschede, Netherlands
- Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
| | - Andrey S Vasenko
- HSE University, 101000 Moscow, Russia
- I. E. Tamm Department of Theoretical Physics, P. N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia
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Schegolev AE, Klenov NV, Bakurskiy SV, Soloviev II, Kupriyanov MY, Tereshonok MV, Sidorenko AS. Tunable superconducting neurons for networks based on radial basis functions. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2022; 13:444-454. [PMID: 35655940 PMCID: PMC9127244 DOI: 10.3762/bjnano.13.37] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
The hardware implementation of signal microprocessors based on superconducting technologies seems relevant for a number of niche tasks where performance and energy efficiency are critically important. In this paper, we consider the basic elements for superconducting neural networks on radial basis functions. We examine the static and dynamic activation functions of the proposed neuron. Special attention is paid to tuning the activation functions to a Gaussian form with relatively large amplitude. For the practical implementation of the required tunability, we proposed and investigated heterostructures designed for the implementation of adjustable inductors that consist of superconducting, ferromagnetic, and normal layers.
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Affiliation(s)
- Andrey E Schegolev
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
- Moscow Technical University of Communication and Informatics (MTUCI), 111024 Moscow, Russia
| | - Nikolay V Klenov
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
- Lobachevsky State University of Nizhni Novgorod Faculty of Physics, 603950 Nizhny Novgorod, Russia
| | - Sergey V Bakurskiy
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
- Dukhov All-Russia Research Institute of Automatics, 101000 Moscow, Russia
| | - Igor I Soloviev
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Mikhail Yu Kupriyanov
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Maxim V Tereshonok
- Moscow Technical University of Communication and Informatics (MTUCI), 111024 Moscow, Russia
| | - Anatoli S Sidorenko
- Institute of Electronic Engineering and Nanotechnologies ASM, MD2028 Kishinev, Moldova
- Laboratory of Functional Nanostructures, Orel State University named after I.S. Turgenev, 302026, Orel, Russia
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Kapran OM, Morari R, Golod T, Borodianskyi EA, Boian V, Prepelita A, Klenov N, Sidorenko AS, Krasnov VM. In situ transport characterization of magnetic states in Nb/Co superconductor/ferromagnet heterostructures. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:913-923. [PMID: 34497739 PMCID: PMC8381831 DOI: 10.3762/bjnano.12.68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/25/2021] [Indexed: 06/13/2023]
Abstract
Employment of the non-trivial proximity effect in superconductor/ferromagnet (S/F) heterostructures for the creation of novel superconducting devices requires accurate control of magnetic states in complex thin-film multilayers. In this work, we study experimentally in-plane transport properties of microstructured Nb/Co multilayers. We apply various transport characterization techniques, including magnetoresistance, Hall effect, and the first-order-reversal-curves (FORC) analysis. We demonstrate how FORC can be used for detailed in situ characterization of magnetic states. It reveals that upon reduction of the external field, the magnetization in ferromagnetic layers first rotates in a coherent scissor-like manner, then switches abruptly into the antiparallel state and after that splits into the polydomain state, which gradually turns into the opposite parallel state. The polydomain state is manifested by a profound enhancement of resistance caused by a flux-flow phenomenon, triggered by domain stray fields. The scissor state represents the noncollinear magnetic state in which the unconventional odd-frequency spin-triplet order parameter should appear. The non-hysteretic nature of this state allows for reversible tuning of the magnetic orientation. Thus, we identify the range of parameters and the procedure for in situ control of devices based on S/F heterostructures.
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Affiliation(s)
- Olena M Kapran
- Department of Physics, Stockholm University, AlbaNova University Center, SE-10691 Stockholm, Sweden
| | - Roman Morari
- Institute of Electronic Engineering and Nanotechnologies, MD2028 Chisinau, Moldova
- Moscow Institute of Physics and Technology, State University, 141700 Dolgoprudny, Russia
| | - Taras Golod
- Department of Physics, Stockholm University, AlbaNova University Center, SE-10691 Stockholm, Sweden
| | - Evgenii A Borodianskyi
- Department of Physics, Stockholm University, AlbaNova University Center, SE-10691 Stockholm, Sweden
| | - Vladimir Boian
- Institute of Electronic Engineering and Nanotechnologies, MD2028 Chisinau, Moldova
| | - Andrei Prepelita
- Institute of Electronic Engineering and Nanotechnologies, MD2028 Chisinau, Moldova
| | - Nikolay Klenov
- Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991, Russia
- Moscow Technical University of Communication and Informatics, 111024 Moscow, Russia
| | - Anatoli S Sidorenko
- Institute of Electronic Engineering and Nanotechnologies, MD2028 Chisinau, Moldova
- Moscow Institute of Physics and Technology, State University, 141700 Dolgoprudny, Russia
- Laboratory of Functional Nanostructures, Orel State University named after I.S. Turgenev, 302026, Russia
| | - Vladimir M Krasnov
- Department of Physics, Stockholm University, AlbaNova University Center, SE-10691 Stockholm, Sweden
- Moscow Institute of Physics and Technology, State University, 141700 Dolgoprudny, Russia
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Theoretical Basis of Quantum-Mechanical Modeling of Functional Nanostructures. Symmetry (Basel) 2021. [DOI: 10.3390/sym13050883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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.
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Sidorenko AS. Functional nanostructures for electronics, spintronics and sensors. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1704-1706. [PMID: 33224700 PMCID: PMC7670112 DOI: 10.3762/bjnano.11.152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 07/25/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Anatolie S Sidorenko
- D. Ghitu Institute of Electronic Engineering and Nanotechnologies, Chisinau, Moldova and Orel State University, Orel, Russia
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