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Temporal fluctuations in the superconducting qubit lifetime, $T_1$, bring up additional challenges in building a fault-tolerant quantum computer. While the exact mechanisms remain unclear, $T_1$ fluctuations are generally attributed to the…

Spin qubits in Silicon quantum dots can have long coherence times, yet their manipulation relies on the exchange interaction, through which charge noise can induce decoherence. Charge traps near the interface of a Si heterostructure lead to…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Dimitrie Culcer , Xuedong Hu , S. Das Sarma

In this study, we examine decoherence of qubits system coupled independently by using influence functional. We especially concentrated on the effect of qubit flip process. We examine the zero-dimensional qubit and one-dimensional qubits…

Quantum Physics · Physics 2008-09-30 Toshifumi Itakura

Few studies explored the dynamics of non-classical correlations besides entanglement in open multipartite quantum systems. Here, we address the time-evolution of quantum discord and entanglement in a model of three non-interacting qubits…

Quantum Physics · Physics 2013-04-11 Fabrizio Buscemi , Paolo Bordone

Electron spins in silicon quantum dots are excellent qubits due to their long coherence times, scalability, and compatibility with advanced semiconductor technology. Although high gate fidelities can be achieved with spin qubits, charge…

Mesoscale and Nanoscale Physics · Physics 2024-12-13 Feiyang Ye , Ammar Ellaboudy , Dylan Albrecht , Rohith Vudatha , N. Tobias Jacobson , John M. Nichol

We investigate a method for entangling two singlet-triplet qubits in adjacent double quantum dots via capacitive interactions. In contrast to prior work, here we focus on a regime with strong interactions between the qubits. The interplay…

Mesoscale and Nanoscale Physics · Physics 2015-12-09 V. Srinivasa , J. M. Taylor

The effects of magnetic and charge noises on the dynamical evolution of the double-dot exchange-only qubit (DEOQ) is theoretically investigated. The DEOQ consisting of three electrons arranged in an electrostatically defined double quantum…

Quantum Physics · Physics 2019-11-14 E. Ferraro , M. Fanciulli , M. De Michielis

We study the dissipative dynamics of a qubit that is afflicted by classical random telegraph noise and it is subject to dynamical decoupling. We derive exact formulas for the qubit dynamics at arbitrary working points in the limit of…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 Joakim Bergli , Lara Faoro

Charge noise in semiconducting quantum dots has been observed to have a 1/f spectrum. We propose a model in which a pair of quantum dots are coupled to a 2D bath of fluctuating two level systems (TLS) that have electric dipole moments and…

Mesoscale and Nanoscale Physics · Physics 2024-03-15 D. L. Mickelsen , Herve M. Carruzzo , Clare C. Yu

In quantum computing, characterizing the full noise profile of qubits can aid in increasing coherence times and fidelities by developing error-mitigating techniques specific to the noise present. This characterization also supports efforts…

We investigate the decay of two-qubit entanglement caused by the influence of classical noise. We consider the whole spectrum of cases ranging from independent to fully correlated noise affecting each qubit. We take into account different…

Quantum Physics · Physics 2015-10-21 P. Szańkowski , M. Trippenbach , Ł. Cywiński , Y. B. Band

Quantum dot-based quantum computation employs extensively the exchange interaction between nearby electronic spins in order to manipulate and couple different qubits. The exchange interaction, however, couples the qubit states to charge…

Mesoscale and Nanoscale Physics · Physics 2021-12-29 Jordi Picó-Cortés , Gloria Platero

The use of single electron spins in quantum dots as qubits requires detailed knowledge about the processes involved in their initialization and operation as well as their relaxation and decoherence. In optical schemes for such spin qubits,…

Mesoscale and Nanoscale Physics · Physics 2024-02-19 Eric Kleinherbers , Hendrik Mannel , Jens Kerski , Martin Geller , Axel Lorke , Jürgen König

We study the entanglement dynamics for two independent superconducting qubits each affected by a bistable impurity generating random telegraph noise (RTN) at pure dephasing. The relevant parameter is the ratio $g$ between qubit-RTN coupling…

We measure telegraph noise of current fluctuations in an electrostatically defined quantum dot in bilayer graphene by real-time detection of single electron tunneling with a capacitively coupled neighboring quantum dot. Suppression of the…

We investigate background charge fluctuation in a GaAs quantum dot device by measuring 1/f noise in the single-electron tunneling current through the dot. The current noise is understood as fluctuations of the confinement potential and…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 S. W. Jung , T. Fujisawa , Y. H. Jeong , Y. Hirayama

Qubit noise and fluctuations of the noise over time are key factors limiting the performance of quantum computers. Characterising them with high temporal resolution is challenging due to multiple overlapping stochastic processes such as…

We propose a model based on a generalized effective Hamiltonian for studying the effect of noise in quantum computations. The system-environment interactions are taken into account by including stochastic fluctuating terms in the system…

Quantum Physics · Physics 2007-05-23 Y. C. Cheng , R. J. Silbey

We consider two interacting electrons in a semiconductor quantum dot structure which consists of a small dot within a larger dot, and demonstrate a singlet-triplet filtering mechanism which involves spin-dependent resonances and can…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 G. Giavaras , J. H. Jefferson , M. Fearn , C. J. Lambert

We study dynamical decoupling of a qubit from non gaussian quantum noise due to discrete sources, as bistable fluctuators and 1/f noise. We obtain analytic and numerical results for generic operating point. For very large pulse frequency,…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 G. Falci , A. D'Arrigo , A. Mastellone , E. Paladino