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The performance of modern quantum devices in communication, metrology or microscopy relies on the quantum-classical interaction which is generally described by the theory of decoherence. Despite the high relevance for long coherence times…

Quantum Physics · Physics 2020-08-26 Nicole Kerker , Robin Röpke , Lea-Marina Steinert , Andreas Pooch , Alexander Stibor

We describe how the effect of charge noise on a pair of spins coupled via the exchange interaction can be calculated by modelling charge fluctuations as a random telegraph noise process using probability density functions. We develop…

Quantum Physics · Physics 2013-05-29 M. J. Testolin , J. H. Cole , L. C. L. Hollenberg

Two-level systems (TLS) are the major source of dephasing of spin qubits in numerous quantum computing platforms. In spite of much effort, it has been difficult to substantially mitigate the effects of this noise or, in many cases, to fully…

Quantum Physics · Physics 2025-07-25 Yujun Choi , S. N. Coppersmith , Robert Joynt

The interference pattern of coherent electrons is effected by coupling to the quantized electromagnetic field. The amplitudes of the interference maxima are changed by a factor which depends upon a double line integral of the photon…

High Energy Physics - Theory · Physics 2011-04-15 L. H. Ford

We discuss the various manifestations of quantum decoherence in the forms of dephasing, entanglement with the environment, and revelation of "which-path" information. As a specific example, we consider an electron interference experiment.…

Quantum Physics · Physics 2015-05-13 Jen-Tsung Hsiang , L. H. Ford

We study decoherence of an electron spin qubit in a quantum dot due to charge noise. We find that at the lowest order, the pure dephasing channel is suppressed for both $1/f$ charge noise and Johnson noise, so that charge noise leads to a…

Mesoscale and Nanoscale Physics · Physics 2014-05-23 Peihao Huang , Xuedong Hu

In this paper, we study the quantum decoherence induced by accumulation of electron tunnelings during the quantum measurement of a charge qubit. The charge qubit is a single electron confined in coupled quantum dots. The measurement of the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Ming-Tsung Lee , Wei-Min Zhang

We study the charge noise $S_Q$ in Josephson qubits produced by fluctuating two level systems (TLS) with electric dipole moments in the substrate. The TLS are driven by an alternating electric field of angular frequency $\Omega$ and…

Superconductivity · Physics 2009-11-13 Magdalena Constantin , Clare C. Yu , John M. Martinis

Entanglement behavior for different classes of two qubit systems passing through a generalized amplitude damping channel is discussed. The phenomena of sudden single, double changes and the sudden death of entanglement are reported for…

Quantum Physics · Physics 2015-06-18 Nasser Metwally

We study intrinsic noise of current in a superconducting single-electron transistor, taking into account both coherence effects and Coulomb interaction near a Cooper-pair resonance. Due to this interplay, the statistics of tunneling events…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Mahn-Soo Choi , Francesco Plastina , Rosario Fazio

We investigate quantum noise effect on the transportation of nonlocal Cooper pairs accross the realistic Andreev entangler which consists of an s-wave superconductor coupled to two small quantum dots at resonance which themselves are…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Emilie Dupont , Karyn Le Hur

We have measured flux-noise correlations in a tunable superconducting flux qubit. The device consists of two loops that independently control the qubit's energy splitting and tunnel coupling. Low frequency flux noise in the loops causes…

We consider pure dephasing of Bell states of electron spin qubits interacting with a sparse bath of nuclear spins. Using the newly developed two-qubit generalization of cluster correlation expansion method, we calculate the spin echo decay…

Mesoscale and Nanoscale Physics · Physics 2018-10-09 Damian Kwiatkowski , Łukasz Cywiński

Fluctuations of electric fields can change the position of a gate-defined quantum dot in a semiconductor heterostructure. In the presence of magnetic field gradient, these stochastic shifts of electron's wavefunction lead to fluctuations of…

Mesoscale and Nanoscale Physics · Physics 2024-08-09 Marcin Kępa , Łukasz Cywiński , Jan A. Krzywda

Addressing the feasibilty of quantum communication with electrons we consider entangled spin states of electrons in a double-dot which is weakly coupled to in--and outgoing leads. We show that the entanglement of two electrons in the…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Daniel Loss , Eugene V. Sukhorukov

We review different attempts to show the decoherence process in double-slit-like experiments both for charged particles (electrons) and neutral particles with permanent dipole moments. Interference is studied when electrons or atomic…

Quantum Physics · Physics 2009-11-11 Fernando C. Lombardo , Paula I. Villar

Quantum entanglement and decoherence are the two counterforces of many quantum technologies and protocols. For example, while quantum teleportation is fueled by a pair of maximally entangled resource qubits, it is vulnerable to decoherence.…

The efficiency of the future devices for quantum information processing will be limited mostly by the finite decoherence rates of the individual qubits and quantum gates. Recently, substantial progress was achieved in enhancing the time…

Mesoscale and Nanoscale Physics · Physics 2014-04-10 E. Paladino , Y. M. Galperin , G. Falci , B. L. Altshuler

By use of a generalized Bloch vector construction, we study the decoherence of a system composed of two interacting qubits in a general noisy environment. In particular, we investigate the effects of correlations in the noise acting on…

Mesoscale and Nanoscale Physics · Physics 2012-07-03 Håkon Brox , Joakim Bergli , Yuri Galperin

Using the axiomatic definition of the coherence measure, such as the $l_{1}$ norm and the relative entropy, we study the phenomena of two-qubit system quantum coherence through quantum channels where successive uses of the channels are…

Quantum Physics · Physics 2016-12-30 You-neng Guo , Ke Zeng , Qing-long Tian , Zheng-da Li