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Related papers: Decoherence in qubits due to low-frequency noise

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It has been proposed that a quantum computer can be constructed based on electron spins in quantum dots or based on a superconducting nanocircuit. During two-qubit operations, the fluctuation of the coupling parameters is a critical factor.…

Materials Science · Physics 2009-11-10 Toshifumi Itakura

In this report, we examine the decoherence of a spin qubits system coupled to counted spin chain with a $1/r^2$ interaction by using influence functional. We also examine the time evolution of density matrix numerically when environment is…

Mesoscale and Nanoscale Physics · Physics 2008-12-20 Toshifumi Itakura

Markovian regime decoherence effects in quantum computers are studied in terms of the fidelity for the situation where the number of qubits N becomes large. A general expression giving the decoherence time scale in terms of Markovian…

Quantum Physics · Physics 2015-06-26 B J Dalton

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

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…

We consider quantum decoherence in solid-state systems by studying the transverse dynamics of a single qubit interacting with a fermionic bath and driven by external pulses. Our interest is in investigating the extent to which the lost…

Mesoscale and Nanoscale Physics · Physics 2008-07-10 R. M. Lutchyn , L. Cywinski , Cody P. Nave , S. Das Sarma

Low-frequency noise presents a serious source of decoherence in solid-state qubits. When combined with a continuous weak measurement of the eigenstates, the low-frequency noise induces a second-order relaxation between the qubit states.…

Quantum Physics · Physics 2011-07-26 L. Tian

When subjected to a classical fluctuating field characterized by a Gaussian process, we examine the {purity} and coherence protection in a three-level quantum system. This symmetry of the three-level system is examined when the local random…

Quantum Physics · Physics 2022-11-30 Sultan Mahmood Zangi , Atta ur Rahman , ZhaoXu Ji , Hazrat Ai , HuanGuo Zhang

We discuss fluctuations in the measurement process and how these fluctuations are related to the dissipational parameter characterising quantum damping or decoherence. On the example of the measuring current of the variable-barrier or QPC…

Quantum Physics · Physics 2008-11-26 L. Stodolsky

Squeezed states of the harmonic oscillator are a common resource in applications of quantum technology. If the noise is suppressed in a nonlinear combination of quadrature operators below threshold for all possible up-to-quadratic…

Quantum Physics · Physics 2023-06-13 Vojtěch Kala , Petr Marek , Radim Filip

Decoherence-Free Subsystems (DFS) are a powerful means of protecting quantum information against noise with known symmetry properties. Although Hamiltonians theoretically exist that can implement a universal set of logic gates on DFS…

Quantum Physics · Physics 2007-05-23 P. Cappellaro , J. S. Hodges , T. F. Havel , D. G. Cory

On the way to solid-state quantum computing, overcoming decoherence is the central issue. In this contribution, we discuss the modeling of decoherence of a superonducting flux qubit coupled to dissipative electronic circuitry. We discuss…

Superconductivity · Physics 2015-06-24 F. K. Wilhelm , M. J. Storcz , C. H. van der Wal , C. J. P. M. Harmans , J. E. Mooij

Reliable processing of quantum information is a milestone to achieve for the deployment of quantum technologies. Uncontrolled, out-of-equilibrium sources of decoherence need to be characterized in detail for designing the control of quantum…

Quantum Physics · Physics 2023-10-26 Martin Kuffer , Analia Zwick , Gonzalo A. Alvarez

When modeling the effects of noise on quantum circuits, one often makes the assumption that these effects can be accounted for by individual decoherence events following an otherwise noise-free gate. In this work, we address the validity of…

Quantum Physics · Physics 2023-12-19 Keith R. Fratus , Juha Leppäkangas , Michael Marthaler , Jan-Michael Reiner

For many implementations of quantum computing, 1/f and other types of broad-spectrum noise are an important source of decoherence. An important step forward would be the ability to back out the characteristics of this noise from qubit…

Quantum Physics · Physics 2013-05-29 Dong Zhou , Robert Joynt

A quantum computer that can be constructed based on a superconducting nanocircuits has previously been proposed. We examine the effect of background charge fluctuations on a coupled Josephson charge qubit system used in such a computer. In…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Toshifumi Itakura , Yasuhiro Tokura

In the past two decades, one of the fascinating subjects in quantum physics has been quantum bits (qubits). Thanks to the superposition principle, the qubits can perform many calculations simultaneously, which will significantly increase…

Quantum Physics · Physics 2023-09-12 H. Zarrabi , S. Hajihosseini , M. Fardmanesh , S. I. Mirzaei

We outline selected trends and results in theoretical modeling of quantum systems in support of the developing research field of quantum information processing. The resulting modeling tools have been applied to semiconductor materials and…

Mesoscale and Nanoscale Physics · Physics 2010-10-12 Vladimir Privman

Noise in entangled quantum systems is difficult to characterize due to many-body effects involving multiple degrees of freedom. This noise poses a challenge to quantum computing, where two-qubit gate performance is critical. Here, we…

Accurate characterization of the noise influencing a quantum system of interest has far-reaching implications across quantum science, ranging from microscopic modeling of decoherence dynamics to noise-optimized quantum control. While the…

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