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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

Controlling the energy spectrum of quantum-coherent superconducting circuits, i.e. the energies of excited states, the circuit anharmonicity and the states' charge dispersion, is essential for designing performant qubits. This control is…

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 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 developed a scheme for a high resolution measurement of the switching current distribution of a current biased Josephson tunnel junction using a timing technique. The measurement setup is implemented such that the digital control…

Superconductivity · Physics 2009-11-07 A. Wallraff , A. Lukashenko , C. Coqui , T. Duty , A. V. Ustinov

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

We theoretically propose and analyze a Josephson-like magnetic tunnel junction (MTJ) structure that exhibits quantum spin dynamics analogous to those in superconducting Josephson junctions. By exploiting the isomorphism between the…

Mesoscale and Nanoscale Physics · Physics 2026-02-17 V. V. Yurlov , P. N. Skirdkov , K. A. Zvezdin , A. K. Zvezdin

With microwave irradiation, the switching current of a Josephson junction coupled to a microscopic two-level system jumps randomly between two discrete states. We modeled the switching process of the coupled system with quantum jump…

Quantum Physics · Physics 2015-05-13 Xueda Wen , Yiwen Wang , Ning Dong , Guozhu Sun , Jian Chen , Lin Kang , Weiwei Xu , Peiheng Wu , Yang Yu

Scaling superconducting quantum processors to large qubit counts faces challenges in control signal delivery, thermal management, and hardware complexity, particularly in achieving microwave signal multiplexing and long-distance quantum…

Quantum Physics · Physics 2025-09-30 Mustafa Bakr

We have theoretically investigated macroscopic quantum tunneling (MQT) and the influence of nodal quasiparticles and zero energy bound states (ZES) on MQT in s-wave/d-wave hybrid Josephson junctions. In contrast to d-wave/d-wave junctions,…

Mesoscale and Nanoscale Physics · Physics 2017-08-23 Shiro Kawabata

We propose to use a time-dependent imaginary potential to describe quantum mechanical tunneling through time-varying potential barriers. We use Gamow solutions for stationary tunneling problems to justify our choice of potential, and we…

Quantum Physics · Physics 2013-05-20 Christian Kraglund Andersen , Klaus Mølmer

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 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 investigate, by experiments and numerical simulations, thermal activation processes of Josephson tunnel junctions in the presence of microwave radiation. When the applied signal resonates with the Josephson plasma frequency oscillations,…

Statistical Mechanics · Physics 2007-08-28 N. Grønbech-Jensen , M. G. Castellano , F. Chiarello , M. Cirillo , C. Cosmelli , V. Merlo , R. Russo , G. Torrioli

Gate-tunable Josephson junctions (JJs) are the backbone of superconducting classical and quantum computation. Typically, these systems exploit low charge concentration materials, and present technological diffculties limiting their…

Mesoscale and Nanoscale Physics · Physics 2019-09-24 Federico Paolucci , Francesco Vischi , Giorgio De Simoni , Claudio Guarcello , Paolo Solinas , Francesco Giazotto

In this paper we discuss solid-state nanoelectronic realizations of Josephson flux qubits with large tunneling amplitude between the two macroscopic states. The latter can be controlled via the height and wells form of the potential…

Superconductivity · Physics 2013-04-02 V. I. Shnyrkov , A. A. Soroka , S. I. Melnik

We report an experimental study on the tuning of supercurrent in a ballistic graphene-based Josephson junction by applying a control voltage to a transverse normal channel. In this four-terminal geometry, the control voltage changes the…

Mesoscale and Nanoscale Physics · Physics 2022-12-21 P. Pandey , D. Beckmann , R. Danneau

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 experimentally investigate the stochastic phase dynamics of planar Josephson junctions (JJs) and superconducting quantum interference devices (SQUIDs) defined in epitaxial InAs/Al heterostructures, and characterized by a large ratio of…

Mesoscale and Nanoscale Physics · Physics 2023-04-27 D. Z. Haxell , E. Cheah , F. Křížek , R. Schott , M. F. Ritter , M. Hinderling , W. Belzig , C. Bruder , W. Wegscheider , H. Riel , F. Nichele

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