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Using a circuit QED device, we demonstrate a simple qubit measurement pulse shape that yields fast ring-up and ring-down of the readout resonator regardless of the qubit state. The pulse differs from a square pulse only by the inclusion of…

Quantum Physics · Physics 2016-02-03 D. T. McClure , Hanhee Paik , L. S. Bishop , M. Steffen , Jerry M. Chow , Jay M. Gambetta

A fundamental goal in the manipulation of quantum systems is the achievement of many coherent oscillations within the characteristic dephasing time T2*[1]. Most manipulations of electron spins in quantum dots have focused on the…

High-fidelity control of superconducting qubits requires carefully shaped microwave pulses that account for multiple error channels. In this work, we present a pedagogical introduction to pulse-shaping techniques for transmon qubits, aiming…

Quantum Physics · Physics 2026-04-24 Animesh Patra , Ankur Raina

We explore the physical limits of pulsed dynamical decoupling methods for decoherence control as determined by finite timing resources. By focusing on a decohering qubit controlled by arbitrary sequences of $\pi$-pulses, we establish a…

Quantum Physics · Physics 2011-04-11 Kaveh Khodjasteh , Tamás Erdélyi , Lorenza Viola

We evaluate various sources of errors that occur when attempting to produce a specified coherent change of a two-state quantum system using six popular coherent control techniques: resonant excitation, adiabatic following, composite…

Quantum Physics · Physics 2021-03-24 Boyan T. Torosov , Bruce W. Shore , Nikolay V. Vitanov

Implementing fast and high-fidelity quantum operations using open-loop quantum optimal control relies on having an accurate model of the quantum dynamics. Any deviations between this model and the complete dynamics of the device, such as…

Quantum Physics · Physics 2024-10-31 Elie Genois , Noah J. Stevenson , Noah Goss , Irfan Siddiqi , Alexandre Blais

The evolution of the quantum wave packet describing an atom trapped in the surface-tip junction of the scanning tunneling microscope is investigated by using the time-dependent Schroedinger equation, and by a quasi-classical Hamiltonian…

Quantum Physics · Physics 2008-02-21 M. Grigorescu

We show that quantum computation can be performed in a system at thermal equilibrium if a spontaneous symmetry breaking occurs. The computing process is associated to the time evolution of the statistical average of the qubit coherence…

Statistical Mechanics · Physics 2007-05-23 F. de Pasquale , S. M. Giampaolo

Qubit readout is a critical part of any quantum computer including the superconducting-qubit-based one. The readout fidelity is affected by the readout pulse width, readout pulse energy, resonator design, qubit design, qubit-resonator…

Quantum Physics · Physics 2024-01-09 Hiu Yung Wong , Yaniv Jacob Rosen , Kristin M. Beck , Prabjot Dhillon

By quickly modifying the shape of the effective potential of a double SQUID flux qubit from a single-well to a double-well condition, we experimentally observe an anomalous behavior, namely an alternance of resonance peaks, in the…

Superconductivity · Physics 2015-06-17 F. Chiarello , S. Spilla , M. G. Castellano , C. Cosmelli , A. Messina , R. Migliore , A. Napoli , G. Torrioli

We analyze a two-level quantum system, describing the phase qubit, during a single-pulse readout process by a numerical solution of the time-dependent Schroedinger equation. It has been demonstrated that the readout error has a minimum for…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Leonid S. Revin , Andrey L. Pankratov

We present a general and exact formalism for finding the evolution of a quantum system subject to external telegraph noise. The various qubit decoherence rates are determined by the eigenvalues of a transfer matrix. The formalism can be…

Quantum Physics · Physics 2009-11-13 Bin Cheng , Qiang-Hua Wang , Robert Joynt

In this paper, we numerically investigate the propulsive performance of three-dimensional pitching flexible plates with varying flexibility and trailing edge shapes. To eliminate the effect of other geometric parameters, only the trailing…

Fluid Dynamics · Physics 2021-10-08 Guojun Li , Gael Kemp , Rajeev Kumar Jaiman , Boo Cheong Khoo

Exact simulations of quantum circuits (QCs) are currently limited to $\sim$50 qubits because the memory and computational cost required to store the QC wave function scale exponentially with qubit number. Therefore, developing efficient…

Quantum Physics · Physics 2025-02-18 Marco Bernardi

We study the quatum to classical transition process in the context of quantum field theory. Extending the influence functional formalism of Feynman and Vernon, we study the decoherence process for self-interacting quantum fields in flat…

General Relativity and Quantum Cosmology · Physics 2009-09-25 Fernando C. Lombardo

A non-equilibrium theory describing the charge qubit dynamics measured by a quantum point contact is developed based on Schwinger-Keldysh's approach. Using the real-time diagram technique, we derive the master equation to all orders in…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Ming-Tsung Lee , Wei-Min Zhang

We present a remarkable finding that a recently discovered [G. S. Uhrig, Phys. Rev. Lett. 98, 100504 (2007)] series of pulse sequences, designed to optimally restore coherence to a qubit in the spin-boson model of decoherence, is in fact…

Quantum Physics · Physics 2009-11-13 B. Lee , W. M. Witzel , S. Das Sarma

We extend profile domain pulsar timing to incorporate wide-band effects such as frequency-dependent profile evolution and broadband shape variation in the pulse profile. We also incorporate models for temporal variations in both pulse width…

Quantum computers, which process information encoded in quantum mechanical systems, hold the potential to solve some of the hardest computational problems. A substantial obstacle for the further development of quantum computers is the fact…

Quantum Physics · Physics 2012-11-02 Alexandre M. Souza , Gonzalo A. Álvarez , Dieter Suter

We describe the coherent manipulation of harmonic oscillator and qubit modes using resonant trains of single flux quantum pulses in place of microwaves. We show that coherent rotations are obtained for pulse-to-pulse spacing equal to the…

Quantum Physics · Physics 2014-08-05 R. McDermott , M. G. Vavilov