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Superconducting circuits rank among the most interesting architectures for the implementation of quantum information processing devices. The recently proposed 0-$\pi$ qubit [Brooks et al., Phys. Rev. A ${\bf 87}$, 52306 (2013)] promises…

Quantum Physics · Physics 2018-05-23 Peter Groszkowski , A. Di Paolo , A. L. Grimsmo , A. Blais , D. I. Schuster , A. A. Houck , Jens Koch

We describe a set up for measurements of low frequency (1 mHz < f < 20 Hz) conductance fluctuations in a solid conductor. The set-up uses a five probe a.c. measurement technique and extensive digital signal processing to reach a noise floor…

Other Condensed Matter · Physics 2007-05-23 Arindam Ghosh , Swastik Kar , Aveek Bid , A. K. Raychaudhuri

Intensity fluctuations in supercontinuum generation are studied in polarization-maintaining (PM) and non-PM all-normal dispersion tellurite photonic crystal fibers. Dispersive Fourier transformation is used to resolve the shot-to-shot…

Liquid-state NMR quantum computer has demonstrated the possibility of quantum computation and supported its development. Using NMR quantum computer techniques, we observed phase decoherence under two kinds of artificial noise fields; one a…

Quantum Physics · Physics 2007-05-23 Yasushi Kondo , Mikio Nakahara , Shogo Tanimura

Conductance fluctuation is usually unavoidable in graphene nanoribbons (GNR) due to the presence of disorder along its edges. By measuring the low-frequency noise in GNR devices, we find that the conductance fluctuation is strongly…

Mesoscale and Nanoscale Physics · Physics 2010-10-12 Guangyu Xu , Carlos M. Torres , Emil B. Song , Jianshi Tang , Jingwei Bai , Xiangfeng Duan , Yuegang Zhang , Kang L. Wang

Continuing our work on the nature and existence of fluctuation-dissipation relations (FDR) in linear and nonlinear open quantum systems [1-3], here we consider such relations when a linear system is in a nonequilibrium steady state (NESS).…

Quantum Physics · Physics 2020-11-11 Jen-Tsung Hsiang , Bei-Lok Hu

Random fluctuations caused by environmental noise can lead to decoherence in quantum systems. Exploring and controlling such dissipative processes is both fundamentally intriguing and essential for harnessing quantum systems to gain…

We consider whether quantum coherence in the form of mutual entanglement between a pair of qubits is susceptible to decay that may be more rapid than the decay of the coherence of either qubit individually. An instance of potential…

Quantum Physics · Physics 2009-11-10 Ting Yu , J. H. Eberly

We report an experimental and theoretical analysis of the energy exchanged between two conductors kept at different temperature and coupled by the electric thermal noise. Experimentally we determine, as functions of the temperature…

Statistical Mechanics · Physics 2015-06-12 Sergio Ciliberto , Alberto Imparato , Antoine Naert , Marius Tanase

Quantum circuits interact with the environment via several temperature-dependent degrees of freedom. Yet, multiple experiments to-date have shown that most properties of superconducting devices appear to plateau out at $T\approx 50$ mK --…

Seemingly unrelated experiments such as electrolyte transport through nanotubes, nano-scale electrochemistry, NMR relaxometry and Surface Force Balance measurements, all probe electrical fluctuations: of the electric current, the charge and…

We investigate the current noise of a charge qubit coupled to a phonon bath in different parameter regimes. We find, using the theory of Full Counting Statistics of non-Markovian systems, that the current fluctuations are strongly…

Mesoscale and Nanoscale Physics · Physics 2008-03-27 Alessandro Braggio , Christian Flindt , Tomas Novotny

Decoherence of quantum objects is critical to modern quantum sciences and technologies. It is generally believed that stronger noises cause faster decoherence. Strikingly, recent theoretical research discovers the opposite case for spins in…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Pu Huang , Xi Kong , Nan Zhao , Fazhan Shi , Pengfei Wang , Xing Rong , Ren-Bao Liu , Jiangfeng Du

We report on critical currents and voltage noise measurements in Niobium strips in the superconducting state, in the presence of a bulk vortex lattice ($B < B_{C2}$) and in the surface superconducting state ($B_{c2}< B < B_{C3}$). For…

Superconductivity · Physics 2009-11-11 J. Scola , A. Pautrat , C. Goupil , Ch. Simon

We calculate the average persistent current in a normal conducting, mesoscopic ring in the diffusive regime. In the presence of magnetic impurities, a contribution to the persistent current is identified, which is related to fluctuations in…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 P. Schwab , U. Eckern

Superconducting circuits fabricated using the widely used shadow evaporation technique can contain unintended junctions which change their quantum dynamics. We discuss a superconducting flux qubit design that exploits the symmetries of a…

Superconductivity · Physics 2007-05-23 Guido Burkard , David P. DiVincenzo , P. Bertet , I. Chiorescu , J. E. Mooij

Qubits based on the magnetic flux degree of freedom require a flux bias, whose stability and precision strongly affect the qubit performance, up to a point of forbidding the qubit operation. Moreover, in the perspective of multiqubit…

Superconductivity · Physics 2009-11-11 Maria Gabriella Castellano , Fabio Chiarello , Guido Torrioli , Pasquale Carelli

The electronic transport in a system of two quantum rings side-coupled to a quantum wire is studied via a single-band tunneling tight-binding Hamiltonian. We derived analytical expressions for the conductance, density of states and the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 P. A. Orellana , M. Pacheco

Noise affects the coherence of qubits and thereby places a bound on the performance of quantum computers. We theoretically study a generic two-level system with fluctuating control parameters in a photonic cavity and find that basic…

Mesoscale and Nanoscale Physics · Physics 2022-06-22 Philipp M. Mutter , Guido Burkard

We investigated decoherence of a Josephson vortex quantum bit (qubit) in dissipative and noisy environment. As the Josephson vortex qubit (JVQ) is fabricated by using a long Josephson junction (LJJ), we use the perturbed sine-Gordon…

Superconductivity · Physics 2009-11-11 Ju H. Kim , Ramesh P. Dhungana , Kee-Su Park