Initial Decoherence in Solid State Qubits

Falci, G.; D’Arrigo, A.; Mastellone, A.; Paladino, E.

doi:10.1103/physrevlett.94.167002

Cited by 145 publications

(180 citation statements)

References 22 publications

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“…The Born-Markov approximation fails for sub-Ohmic baths due to the presence of low frequency modes which cause large correlation times and strong memory effects. It is generally recognised that non-Markovian effects lead to stronger decoherence than that described by the simple Markov rate, and at present there is much discussion of non-Markovian dynamics in the context of qubit decoherence rates 16,17,18,19 .…”

Section: Tls Dynamics and Limitations Of The Variational Methodsmentioning

confidence: 99%

Coherent-incoherent transition in the sub-Ohmic spin-boson model

Chin

Turlakov

2006

Phys. Rev. B

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We study the spin-boson model with a sub-Ohmic bath using a variational method. The transition from coherent dynamics to incoherent tunneling is found to be abrupt as a function of the coupling strength α and to exist for any power 0 < s < 1, where the bath coupling is described by J(ω) ∼ αω s . We find non-monotonic temperature dependence of the two-level gapK and a re-entrance regime close to the transition due to non-adiabatic low-frequency bath modes. Differences between thermodynamic and dynamic conditions for the transition as well as the limitations of the simplified bath description are discussed.

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Section: Tls Dynamics and Limitations Of The Variational Methodsmentioning

confidence: 99%

Coherent-incoherent transition in the sub-Ohmic spin-boson model

Chin

Turlakov

2006

Phys. Rev. B

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“…The 1/f -noise essentially determines the magnitude of the dephasing part of the decoherence. Thus, it is in turn possible to impose for the zero frequency component J(0) the experimental value of the dephasing rates or a value from a microscopic model 32 . However, in many cases it turns out to be non-Markovian and/or non-Gaussian, leading to non-exponential decay, which can neither be described by Bloch-Redfield theory nor parameterized by a single rate.…”

Section: A One Common Phonon Bathmentioning

confidence: 99%

Intrinsic phonon decoherence and quantum gates in coupled lateral quantum-dot charge qubits

et al. 2005

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Recent experiments by Hayashi et al. [Phys. Rev. Lett. 91, 226804 (2003)] demonstrate coherent oscillations of a charge quantum bit (qubit) in laterally defined quantum dots. We study the intrinsic electron-phonon decoherence and gate performance for the next step: a system of two coupled charge qubits. The effective decoherence model contains properties of local as well as collective decoherence. Decoherence channels can be classified by their multipole moments, which leads to different lowenergy spectra. It is shown that due to the super-Ohmic spectrum, the gate quality is limited by the single-qubit Hadamard gates. It can be significantly improved, by using double-dots with weak tunnel coupling.

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“…In general T 2 < 2T 1 due to dephasing. [33] The pure dephasing time T ϕ is related to T 1 and T 2 by [56] 1…”

Section: Relaxation and Decoherence In The Absence Of Ac Drivingmentioning

confidence: 99%

“…For this reason, environment-induced decoherence has been and is still a main obstacle to the practical application of superconducting qubits in quantum computation. [2,13,14,15,16] The environment-induced decoherence of superconducting qubits has been extensively studied both theoretically [15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33] and experimentally [2,8,13,21,25,34,35,36,37,38,39,40] in the absence of ac driving fields (free decay). Quite a few proposals, such as dynamical decoupling, [41,42,43,44,45,46,47,48] decoherence free subspaces, [49,50,51,52] spin echoes, …”

Section: Introductionmentioning

confidence: 99%

Relaxation and decoherence in a resonantly driven qubit

Zhou

Chu

Han

2008

J. Phys. B: At. Mol. Opt. Phys.

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Relaxation and decoherence of a qubit coupled to environment and driven by a resonant ac field are investigated by analytically solving Bloch equation of the qubit. It is found that the decoherence of a driven qubit can be decomposed into intrinsic and field-dependent ones. The intrinsic decoherence time equals to the decoherence time of the qubit in free decay while the fielddependent decoherence time is identical with the relaxation time of the qubit in driven oscillation. Analytical expressions of the relaxation and decoherence times are derived and applied to study a microwave-driven SQUID flux qubit. The results are in excellent agreement with those obtained by numerically solving the master equation. The relations between the relaxation and decoherence times of a qubit in free decay and driven oscillation can be used to extract the decoherence and thus dephasing times of the qubit by measuring its population evolution in free decay and resonantly driven oscillation.

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Initial Decoherence in Solid State Qubits

Cited by 145 publications

References 22 publications

Coherent-incoherent transition in the sub-Ohmic spin-boson model

Coherent-incoherent transition in the sub-Ohmic spin-boson model

Intrinsic phonon decoherence and quantum gates in coupled lateral quantum-dot charge qubits

Relaxation and decoherence in a resonantly driven qubit

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