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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 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

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 the observation of quantum jumps between macroscopic quantum states in a superconducting phase qubit coupled to the two-level systems in the Josephson tunnel junction, and all key features of quantum jumps are confirmed in the…

Quantum Physics · Physics 2009-11-13 Yang Yu , Shi-Liang Zhu , Guozhu Sun , Xueda Wen , Ning Dong , Jian Chen , Peiheng Wu , Siyuan Han

There is a wide recognition that Josephson-junction-like structures intrinsic to the layered cuprate high temperature superconductors offer an attractive stage for exploiting possible applications to new quantum technologies. On the other…

Superconductivity · Physics 2007-05-23 K. Inomata , S. Sato , K. Nakajima , A. Tanaka , Y. Takano , H. B. Wang , M. Nagao , S. Kawabata , T. Hatano

Theoretically, Josephson junction (JJ) arrays can exhibit either a superconducting or insulating state, separated by a quantum phase transition (QPT). In this work, we analyzed published data on QPTs in three one-dimensional arrays and two…

Superconductivity · Physics 2024-11-12 Samuel Feldman , Andrey Rogachev

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

Prototype Josephson-junction based qubit coherence times are too short for quantum computing. Recent experiments probing superconducting phase qubits have revealed previously unseen fine splittings in the transition energy spectra. These…

Macroscopic quantum tunneling of the phase is a fundamental phenomenon in the quantum dynamics of superconducting nanocircuits. The tunneling rate can be controlled in such circuits, where the potential landscape for the phase can be tuned…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 Nicolas Didier , Frank W. J. Hekking

We investigate the effects of high-Q_c resonant cavity on macroscopic quantum tunneling (MQT) of fluxon both from a metastable state to continuum and from one degenerate ground-state of a double-well potential to the other. By using a set…

Superconductivity · Physics 2015-05-27 Ju H. Kim , Ramesh P. Dhungana

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,…

Superconductivity · Physics 2009-11-17 S. Kawabata , A. A. Golubov , Ariando , C. J. M. Verwijs , H. Hilgenkamp , J. R. Kirtley

We consider a symmetric 0-pi Josephson junction of length $L$, which classically can be in one of two degenerate ground states up or down, corresponding to supercurrents circulating clockwise or counterclockwise around the 0-pi boundary.…

Superconductivity · Physics 2010-03-02 E. Goldobin , K. Vogel , W. P. Schleich , D. Koelle , R. Kleiner

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

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

The non-dissipative non-linearity of a Josephson junction converts macroscopic superconducting circuits into artificial atoms, enabling some of the best controlled quantum bits (qubits) today. Three fundamental types of superconducting…

The macroscopic quantum tunneling (MQT) in the current biased high-Tc superconductor Josephson junctions and the effect of the zero energy bound states (ZES) on the MQT are theoretically investigated. We obtained the analytical formula of…

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

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

Mesoscopic multi-terminal Josephson junctions are novel devices that provide weak coupling between several bulk superconductors through a common normal layer. Because of the nonlocal coupling of the superconducting banks, a current flow…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 M. H. S. Amin , A. N. Omelyanchouk , A. Blais , A. Maassen van den Brink , G. Rose , T. Duty , A. M. Zagoskin

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 study quantum phase-slip (QPS) processes in a superconducting ring containing N Josephson junctions and threaded by an external static magnetic flux. In a such system, a QPS consists of a quantum tunneling event connecting two distinct…

Superconductivity · Physics 2015-03-19 G. Rastelli , I. M. Pop , F. W. J. Hekking