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We investigated macroscopic quantum tunneling (MQT) of Bi$_2$Sr$_2$CaCu$_2$O$_y$ intrinsic Josephson junctions (IJJs) with two device structures. One is a nanometer-thick small mesa structure with only two or three IJJs and the other is a…

Superconductivity · Physics 2009-11-13 K. Ota , K. Hamada , R. Takemura , M. Ohmaki , T. Machi , K. Tanabe , M. Suzuki , A. Maeda , H. Kitano

Quantum phase diffusion in a small underdamped Nb/AlO$_x$/Nb junction ($\sim$ 0.4 $\mu$m$^2$) is demonstrated in a wide temperature range of 25-140 mK where macroscopic quantum tunneling (MQT) is the dominant escape mechanism. We propose a…

Superconductivity · Physics 2015-05-27 H. F. Yu , X. B. Zhu , Z. H. Peng , Ye Tian , D. J. Cui , G. H. Chen , D. N. Zheng , X. N. Jing , Li Lu , S. P. Zhao , Siyuan Han

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 have investigated macroscopic quantum tunneling in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ intrinsic Josephson junctions at millikelvin temperatures using microwave irradiation. Measurements show that the escape rate for uniformly switching…

Superconductivity · Physics 2007-05-23 X. Y. Jin , J. Lisenfeld , Y. Koval , A. Lukashenko , A. V. Ustinov , P. Müller

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 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 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

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

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 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 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

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

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 switching dynamics of current-biased Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ intrinsic Josephson junctions (IJJs) was studied to clarify the effect of d-wave superconductivity and the stack structure on the switching properties. High…

Superconductivity · Physics 2008-11-07 H. Kashiwaya , T. Matsumoto , H. Shibata , S. Kashiwaya , H. Eisaki , Y. Yoshida , S. Kawabata , Y. Tanaka

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

Stochastic switching-current distribution in a graphene-based Josephson junction exhibits a crossover from the classical to quantum regime, revealing the macroscopic quantum tunneling (MQT) of a Josephson phase particle at low temperatures.…

Mesoscale and Nanoscale Physics · Physics 2012-11-15 Gil-Ho Lee , Dongchan Jeong , Jae-Hyun Choi , Yong-Joo Doh , Hu-Jong Lee

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 the intrinsic Josephson properties in slightly underdoped (Hg,Re)Ba2Ca2Cu3Oy [Hg(Re)1223] intrinsic Josephson junctions (IJJs) with a dimension of 1.0x1.5x0.11 um^3. The current-voltage characteristics of the IJJs…

Superconductivity · Physics 2009-11-10 S. Ueda , T. Yamaguchi , Y. Kubo , S. Tsuda , J. Shimoyama , K. Kishio , Y. Takano

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

Macroscopic quantum tunneling (MQT) for a single fluxon moving along a long Josephson junction is studied theoretically. To introduce a fluxon-pinning force, we consider inhomogeneities made by modifying thickness of an insulating layer…

Condensed Matter · Physics 2009-10-28 Takeo Kato , Masatoshi Imada
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