Showing papers by "Paul Seidel published in 2017"
19 citations
TL;DR: In this article, a model of intrinsic Josephson junctions shunted by LC-elements (L-inductance, C-capacitance) is studied and the phase dynamics and IV-characteristics are investigated in detail when the Josephson frequency approaches the frequency of the resonance circuit.
Abstract: Resonance phenomena in a model of intrinsic Josephson junctions shunted by LC-elements (L-inductance, C-capacitance) are studied. The phase dynamics and IV-characteristics are investigated in detail when the Josephson frequency approaches the frequency of the resonance circuit. A realization of parametric resonance through the excitation of a longitudinal plasma wave, within the bias current interval corresponding to the resonance circuit branch, is demonstrated. It is found that the temporal dependence of the total voltage of the stack, and the voltage measured across the shunt capacitor, reflect the charging of superconducting layers, a phenomenon which might be useful as a means of detecting such charging experimentally. Thus, based on the voltage dynamics, a novel method for the determination of charging in the superconducting layers of coupled Josephson junctions is proposed. A demonstration and discussion of the influence of external electromagnetic radiation on the IV-characteristics and charge-time dependence is given. Over certain parameter ranges the radiation causes an interesting new type of temporal splitting in the charge-time oscillations within the superconducting layers.
19 citations
TL;DR: In this paper, the properties of stacks of two inductively interacting long Josephson junctions with the homogeneous and inhomogeneous distributions of critical currents were investigated numerically, and strong coherent emission was found at the step which corresponds to the frequency of in-phase oscillations.
Abstract: IV-characteristics of stacks of two inductively interacting long Josephson junctions with the homogeneous and inhomogeneous distributions of critical currents were investigated numerically. It was assumed that the inhomogeneous linear distribution of critical currents along the junction was created by heating of one end of the stack. Even zero-field steps were found in the IV-curve of the stack with the homogeneous distribution of critical currents, whereas odd zero-field steps appeared in the IV-curve of the stack with the heated end. Due to the inductive interaction between junctions in a stack of two junctions, each of the zero-field steps splits into two steps which correspond to frequencies of collective excitations in the system. Strong coherent emission was found at the step which corresponds to the frequency of in-phase oscillations.
7 citations
TL;DR: In this article, the authors investigated numerically ac power of emission at zero-field steps in IV-characteristics of a stack of two inductively coupled long Josephson junctions as well as emission from the solitary long junction.
Abstract: In order to study the origin of coherent emission of intrinsic junctions in high-temperature superconductors, we investigated numerically ac power of emission at zero-field steps in IV-characteristics of a stack of two inductively coupled long Josephson junctions as well as emission from the solitary long junction. We found that zero-field steps appeared due to noise, random distribution of critical currents or due to normal edges of junctions in the stack. Due to the formation of collective excitations in the stack of coupled junctions, the zero-field step was split into two steps, which correspond to two normal modes of excitations. We investigated the dependence of heights of steps on the length of the stack and found that there existed two different threshold values of the length, so above the threshold length the zero-field step existed and below the threshold length it vanished. We calculated the dependence of ac power on the length of the stack and found the optimal value of the length for larger emission.
6 citations
Posted Content•
TL;DR: In this paper, the authors show that the differential conductance-vs-voltage spectrum of the hybrid fork structure varies considerably when the extra link between the two superconducting leads is added and it can serve as an indicator of quantum correlations which manifest themselves in the quantum Braess paradox.
Abstract: The Braess paradox encountered in classical networks is a counterintuitive phenomenon when the flow in a road network can be impeded by adding a new road or, more generally, the overall net performance can degrade after addition of an extra available choice. In this work, we discuss the possibility of a similar effect in a phase-coherent quantum transport and demonstrate it by example of a simple Y-shaped metallic fork. To reveal the Braess-like partial suppression of the charge flow in such device, it is proposed to transfer two outgoing arms into a superconducting state. We show that the differential conductance-vs-voltage spectrum of the hybrid fork structure varies considerably when the extra link between the two superconducting leads is added and it can serve as an indicator of quantum correlations which manifest themselves in the quantum Braess paradox.
1 citations
TL;DR: In this article, the authors discuss the possibility of a similar effect in a phase-coherent quantum transport and demonstrate it by example of a simple Y-shaped metallic fork, and reveal the Braess-like partial suppression of the charge flow in such device, it is proposed to transfer two outgoing arms into a superconducting state.
Abstract: The Braess paradox encountered in classical user-optimized network system, such as a transportation network, is a counter intuitive phenomenon when the travel cost (time) for every user can be increased by adding a new road or, more generally, when the overall net performance can degrade after addition of an extra available choice. In this work, we discuss the possibility of a similar effect in a phase-coherent quantum transport and demonstrate it by example of a simple Y-shaped metallic fork. To reveal the Braess-like partial suppression of the charge flow in such device, it is proposed to transfer two outgoing arms into a superconducting state. We show that the differential conductance-vs. voltage spectrum of the hybrid fork structure varies considerably when the extra link between the two superconducting leads is added and it can serve as an indicator of quantum correlations which manifest themselves in the quantum Braess paradox.
1 citations
Posted Content•
TL;DR: In this article, the phase dynamics and IV-characteristics of DC-SQUIDs consisting of Josephson junctions with topologically nontrivial barriers, which cause the appearance of Majorana bound state are studied.
Abstract: We study the phase dynamics and IV--characteristics of DC--SQUIDs consisting of Josephson junctions with topologically nontrivial barriers, which cause the appearance of Majorana bound state. Its comparative analysis with the trivial case is performed. The influence of external electromagnetic radiation is considered and the analysis of the amplitude dependence of the Shapiro step widths is performed. We have shown that in nontrivial case the width of even harmonic of Shapiro step is larger than width of odd harmonic. In the presence of external dc magnetic field a beating state is realized in the DC--SQUID, which leads to a resonance branch in the IV--curve. We show that in the presence of resonance branch the maximum width of Shapiro step and periods of its amplitude dependence are decreased in comparison of situation without resonance in both trivial and nontrivial cases. We demonstrate that in the presence of the resonance branch the chaotic behavior of IV--curve is reduced.
24 Nov 2017
TL;DR: In this article, the authors proposed a new method for solid state physics and applied it at the CERN European Organization for Nuclear Research (CERN) European Organization of Nuclear Research, CH-1211 Geneva, Switzerland
Abstract: Institute for Solid State Physics, Friedrich Schiller University, D-07743 Jena, Germany 1 Institute for Solid State Physics, Friedrich Schiller University, D-07743 Jena, Germany 2 Institute for Optics and Quantum Electronics, Friedrich Schiller University, D-07743 Jena, Germany 3 Helmholtz Institute Jena, D-07743 Jena, Germany 4 GSI Helmholtz Center for Heavy Ion Research, D-64291 Darmstadt, Germany 5 The Cockcroft Institute, University of Liverpool, Daresbury, Cheshire WA4 4AD, U.K 6 CERN European Organization for Nuclear Research, CH-1211 Geneva, Switzerland