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We analyze theoretically the decoherence of two interacting electrons in a double self-assembled quantum dot due to a random telegraph noise. For this purpose we have examined the pure dephasing rate by evaluating the decoherence factor.…

Mesoscale and Nanoscale Physics · Physics 2014-03-03 A. Ayachi , W. Ben Chouikha , S. Jaziri , R. Bennaceur

Singlet-triplet qubits in lateral quantum dots in semiconductor heterostructures exhibit high-fidelity single-qubit gates via exchange interactions and magnetic field gradients. High-fidelity two-qubit entangling gates are challenging to…

Mesoscale and Nanoscale Physics · Physics 2017-12-06 M. A. Wolfe , F. A. Calderon-Vargas , J. P. Kestner

Electron spins in silicon quantum dots are promising qubits due to their long coherence times, scalable fabrication, and potential for all-electrical control. However, charge noise in the host semiconductor presents a major obstacle to…

Mesoscale and Nanoscale Physics · Physics 2022-02-21 Elliot J. Connors , JJ Nelson , Lisa F. Edge , John M. Nichol

Within a numerically exact simulation technique, the dissipative dynamics of a two-qubit architecture is considered in which each qubit couples to its individual noise source (reservoir). The goal is to reveal the role of subtle…

Quantum Physics · Physics 2026-04-14 Kiyoto Nakamura , Joachim Ankerhold

We study the dynamics of quantum dissension for three qubit states in various dissipative channels such as amplitude damping, dephasing and depolarizing. Our study is solely based on Markovian environments where quantum channels are without…

Quantum Physics · Physics 2014-12-01 Pratik K. Sarangi , Indranil Chakrabarty

We theoretically consider the temporal dynamics of two coupled spin qubits (e.g., semiconductor quantum dots) driven by the inter-qubit spin-spin coupling. The presence of environmental noise (e.g., charge traps, nuclear spins, random…

Mesoscale and Nanoscale Physics · Physics 2016-07-29 S. Das Sarma , Robert E. Throckmorton , Yang-Le Wu

Entangled qubit pairs can serve as a quantum memory or as a resource for quantum communication. The utility of such pairs is measured by how long they take to disentangle or decohere. To answer the question of whether qubit-qubit…

Mesoscale and Nanoscale Physics · Physics 2013-03-05 Amrit De , Alex Lang , Dong Zhou , Robert Joynt

We study competition between the dissipative and coherent effects in the entanglement dynamics of two qubits. The coherent interactions are needed for designing logic gate operations with systems like ion traps, semicondutor quantum dots…

Quantum Physics · Physics 2009-11-23 Sumanta Das , G S Agarwal

Understanding error mechanisms in two-qubit gate operations is essential for building high-fidelity quantum processors. While prior studies predominantly treat dephasing noise as either Markovian or predominantly low-frequency, realistic…

Superconducting circuits are a leading platform for quantum computing. However, their coherence times are still limited and exhibit temporal fluctuations. Those phenomena are often attributed to the coupling between qubits and material…

Quantum Physics · Physics 2022-10-13 Xinyuan You , Ziwen Huang , Ugur Alyanak , Alexander Romanenko , Anna Grassellino , Shaojiang Zhu

We consider dissipative dynamics of a flux qubit caused by 1/f noises, which act both on the shunting LC-contour and on the SQUID loop. These classical Gaussian noises modulate of the level splitting and of the tunnel coupling,…

Mesoscale and Nanoscale Physics · Physics 2018-07-25 F. T. Vasko

Singlet-triplet spin qubits in six-electron double quantum dots, in moderate magnetic fields, can show superior immunity to charge noise. This immunity results from the symmetry of orbitals in the second energy shell of circular quantum…

Mesoscale and Nanoscale Physics · Physics 2014-08-06 Sebastian Mehl , David P. DiVincenzo

Quantum dots are nanometer-scale semiconductor particles that exhibit size-dependent quantum mechanical properties. In this work, we investigate the dynamics of quantum correlations, quantified by the concurrence and the quantum coherence,…

We study a pair of capacitively coupled singlet-triplet spin qubits. We characterize the two-qubit decoherence through two complementary measures, the decay time of coupled-qubit oscillations and the fidelity of entangled state preparation.…

Mesoscale and Nanoscale Physics · Physics 2017-10-11 Yang-Le Wu , S. Das Sarma

Decoherence due to charge noise is one of the central challenges in using spin qubits in semiconductor quantum dots as a platform for quantum information processing. Recently, it has been experimentally demonstrated in both Si and GaAs…

Mesoscale and Nanoscale Physics · Physics 2017-05-30 Chengxian Zhang , Robert E. Throckmorton , Xu-Chen Yang , Xin Wang , Edwin Barnes , S. Das Sarma

We analyze local spin-echo procedures to protect entanglement between two non-interacting qubits, each subject to pure-dephasing random telegraph noise. For superconducting qubits this simple model captures characteristic features of the…

Spin-orbit coupling is ubiquitous in quantum dot quantum computing architectures, and makes spin qubits susceptible to charge noise. We derive a Hamiltonian describing the effect of spin-orbit and noise on a single-spin qubit in a quantum…

Mesoscale and Nanoscale Physics · Physics 2014-11-14 Adam Bermeister , Daniel Keith , Dimitrie Culcer

We present a quantum open-system approach to analyze the nonunitary dynamics of a superconducting qubit when it evolves under the influence of external noise. We consider the presence of longitudinal and transverse environmental…

Quantum Physics · Physics 2015-06-18 Fernando C. Lombardo , Paula I. Villar

Two level systems that can be reliably controlled and measured hold promise in both metrology and as qubits for quantum information science (QIS). When prepared in a superposition of two states and allowed to evolve freely, the state of the…

Mesoscale and Nanoscale Physics · Physics 2013-04-09 O. E. Dial , M. D. Shulman , S. P. Harvey , H. Bluhm , V. Umansky , A. Yacoby

Quantum information transport over micron to millimeter scale distances is critical for the operation of practical quantum processors based on spin qubits. One method of achieving a long-range interaction is by coherent electron spin…

Mesoscale and Nanoscale Physics · Physics 2024-12-18 Natalie D. Foster , Jacob D. Henshaw , Martin Rudolph , Dwight R. Luhman , Ryan M. Jock