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We investigate classical thermal activation (TA) and macroscopic quantum tunneling (MQT) for a Josephson junction coupled with an LC circuit theoretically. The TA and MQT escape rate are calculated analytically by taking into account the…

Superconductivity · Physics 2015-05-14 Shiro Kawabata , Takeo Kato , Thilo Bauch

We investigate classical thermal activation (TA) and macroscopic quantum tunneling (MQT) for a YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO) Josephson junction coupled to an LC circuit theoretically. Due to the coupling between the junction and the LC…

Superconductivity · Physics 2009-11-16 Shiro Kawabata , Thilo Bauch , Takeo Kato

Low-temperature characters of superconducting devices yield definite probes for different superconducting phenomena. We study the macroscopic quantum tunneling (MQT) in a Josephson junction, composed of a single-gap superconductor and a…

Superconductivity · Physics 2014-12-19 Hidehiro Asai , Shiro Kawabata , Yukihiro Ota , Masahiko Machida

We present a quantitative analysis of an escape rate for switching from the superconducting state to a resistive one in series arrays of globally coupled Josephson junctions. A global coupling is provided by an external shunting impedance.…

Superconductivity · Physics 2015-06-25 M. V. Fistul

We theoretically study the macroscopic quantum tunneling (MQT) in a hetero Josephson junction formed by a conventional single-gap superconductor and a multi-gap one such as ${MgB}_{2}$ and iron-based superconductors. In such a Josephson…

Quantum Physics · Physics 2011-02-11 Yukihiro Ota , Masahiko Machida , Tomio Koyama

Collective excitations reveal fundamental properties and potential applications of superconducting states. We theoretically study macroscopic quantum tunneling (MQT) in a Josephson junction composed of multi-band superconductors, focusing…

Superconductivity · Physics 2014-07-14 Hidehiro Asai , Yukihiro Ota , Shiro Kawabata , Masahiko Machida , Franco Nori

We present a theoretical study of an escape rate for switching from the superconducting state to a resistive one in series arrays of strongly interacting Josephson junctions. At low temperatures such a switching is determined by macroscopic…

Superconductivity · Physics 2007-05-23 M. V. Fistul

We performed measurements of switching current distribution in a submicron La$_{2-x}$Sr$_x$CuO$_4$ (LSCO) intrinsic Josephson junction (IJJ) stack in a wide temperature range. The escape rate saturates below approximately 2\,K, indicating…

Superconductivity · Physics 2015-03-19 Yuimaru Kubo , A. O. Sboychakov , Franco Nori , Y. Takahide , S. Ueda , I. Tanaka , A. T. M. N. Islam , Y. Takano

We have measured the influence of shot noise on hysteretic Josephson junctions initially in macroscopic quantum tunnelling (MQT) regime. Escape threshold current into the resistive state decreases monotonically with increasing average…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 J. P. Pekola , T. E. Nieminen , M. Meschke , J. M. Kivioja , A. O. Niskanen , J. J. Vartiainen

We study the phenomenon of macroscopic quantum tunneling (MQT) in small Josephson junctions (JJ) with an externally applied magnetic field. The latter results in the appearance of the Fraunhofer type modulation of the current density along…

Superconductivity · Physics 2009-11-13 Yu. N. Ovchinnikov , A. Barone , A. A. Varlamov

We report a theoretical study of the macroscopic quantum tunneling (MQT) in small Josephson junctions containing randomly distributed two-level systems. We focus on the magnetic field dependent crossover temperature $T_{cr}$ between the…

Superconductivity · Physics 2014-10-17 M. V. Fistul

We study the phenomenon of macroscopic quantum tunneling (MQT) in a finite size Josephson junction (JJ) with an externally applied magnetic field. As it is well known, the problem of MQT in a point-like JJ is reduced to the study of the…

Superconductivity · Physics 2008-07-18 Yu. N. Ovchinnikov , A. Barone , A. A. Varlamov

We have investigated macroscopic quantum tunneling (MQT) in in-plane high-Tc superconductor Josephson junctions and the influence of the nodal-quasiparticle and the zero energy bound states (ZES) on MQT. We have shown that the presence of…

We examine the macroscopic quantum tunneling (MQT) in high-Tc superconductor Josephson junctions with a d-wave order parameter. Using microscopic Hamiltonian and the functional integral method, we analytically obtain the MQT rate (the…

Superconductivity · Physics 2009-11-10 Shiro Kawabata , Satoshi Kashiwaya , Yasuhiro Asano , Yukio Tanaka

In close analogy to quantum electrodynamics, we derive a quantum field theory of Josephson plasma waves (JPWs) in layered superconductors (LSCs), which describes two types of interacting JPW bosonic quanta: one massive and the other…

Superconductivity · Physics 2007-05-23 Sergey Savel'ev , A. L. Rakhmanov , Franco Nori

We have carried out systematic Macroscopic Quantum Tunneling (MQT) experiments on Nb/Al-AlO_x/Nb Josephson junctions (JJs) of different areas. Employing on-chip lumped element inductors, we have decoupled the JJs from their environmental…

Superconductivity · Physics 2010-11-19 Christoph Kaiser , Roland Schäfer , Michael Siegel

The evidence for macroscopic quantum tunneling (MQT) in Josephson junctions at low temperatures has been reassessed. Swept bias escape distributions have been modeled with an algorithm-based simulation and the results compared with data…

Superconductivity · Physics 2017-10-26 James A. Blackburn , Matteo Cirillo , Niels Gronbech-Jensen

We propose a theory for photon-assisted macroscopic quantum tunneling (MQT) in a stack of capacitively-coupled intrinsic Josephson junctions in which the longitudinal Josephson plasma, i.e., longitudinal collective phase oscillation modes,…

Superconductivity · Physics 2009-11-11 Masahiko Machida , Tomio Koyama

We investigate macroscopic dynamical quantum tunneling (MDQT) in the driven Duffing oscillator, charateristic for Josephson junction physics and nanomechanics. Under resonant conditions between stable coexisting states of such systems we…

Superconductivity · Physics 2008-04-01 I. Serban , F. K. Wilhelm

We study macroscopic quantum tunneling (MQT) in c-axis twist Josephson junctions made of high-T_c superconductors in order to clarify the influence of the anisotropic order parameter symmetry (OPS) on MQT. The dependence of the MQT rate on…

Superconductivity · Physics 2009-11-13 Takehito Yokoyama , Shiro Kawabata , Takeo Kato , Yukio Tanaka
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