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We propose an experimentally feasible scheme to achieve quantum computation based on a pair of orthogonal cyclic states. In this scheme, quantum gates can be implemented based on the total phase accumulated in cyclic evolutions. In…

Quantum Physics · Physics 2009-11-07 Shi-Liang Zhu , Z. D. Wang

Raman qubits, represented by two ground or metastable quantum states coupled via an intermediate state, hold some advantages over directly coupled qubits, most notably much longer radiative lifetimes, shorter gate duration and lower…

Quantum Physics · Physics 2023-10-09 Stancho G. Stanchev , Nikolay V. Vitanov

We describe a method for achieving arbitrary 1-qubit gates and controlled-NOT gates within the context of the Single Cooper Pair Box (SCB) approach to quantum computing. Such gates are sufficient to support universal quantum computation.…

Quantum Physics · Physics 2007-05-23 P. Echternach , C. P. Williams , S. C. Dultz , P. Delsing , S. L. Braunstein , J. P. Dowling

Open quantum systems can undergo dissipative phase transitions, and their critical behavior can be exploited in sensing applications. For example, it can be used to enhance the fidelity of superconducting qubit readout measurements, a…

Quantum Physics · Physics 2021-12-13 Enrico Rinaldi , Roberto Di Candia , Simone Felicetti , Fabrizio Minganti

The optimal quantum control theory is employed to determine electric pulses capable of producing quantum gates with high fidelity (higher than 0.9997). Particularly, these quantum gates were chosen to perform the permutation algorithm (Z.…

Quantum Physics · Physics 2018-03-28 C. M. Rivera-Ruiz , E. F. de Lima , F. F. Fanchini , V. Lopez-Richard , L. K. Castelano

We present a solid-state implementation of ultrafast conditional quantum gates. Our proposal for a quantum-computing device is based on the spin degrees of freedom of electrons confined in semiconductor quantum dots, thus benefiting from…

Condensed Matter · Physics 2015-06-24 E. Pazy , E. Biolatti , T. Calarco , I. D'Amico , P. Zanardi , F. Rossi , P. Zoller

We describe an approach for characterizing the process of quantum gates using quantum process tomography, by first modeling them in an extended Hilbert space, which includes non-qubit degrees of freedom. To prevent unphysical processes from…

Quantum Physics · Physics 2008-11-26 Peter P. Rohde , G. J. Pryde , J. L. O'Brien , Timothy C. Ralph

In this paper, with the weak cross-Kerr nonlinearity, we first present a special experimental scheme called C-path gate with which the realization of all possible bipartite POVMs of two-photon polarization states can be simpler and nearly…

Quantum Physics · Physics 2009-02-26 Qing Lin , Jian Li

Adiabatic state engineering is a powerful technique in quantum information and quantum control. However, its performance is limited by the adiabatic theorem of quantum mechanics. In this scenario, shortcuts to adiabaticity, such as provided…

Quantum Physics · Physics 2015-11-03 Alan C. Santos , Marcelo S. Sarandy

This paper provides necessary and sufficient conditions for constructing a universal quantum computer over continuous variables. As an example, it is shown how a universal quantum computer for the amplitudes of the electromagnetic field…

Quantum Physics · Physics 2009-10-31 Seth Lloyd , Samuel L. Braunstein

The quantum permutation algorithm provides computational speed-up over classical algorithms in determining the parity of a given cyclic permutation. For its $n$-qubit implementations, the number of required quantum gates scales…

Quantum Physics · Physics 2018-01-01 İ. Yalçınkaya , Z. Gedik

Fast entangling gate operations are a fundamental prerequisite for quantum simulation and computation. We propose an entangling scheme for arbitrary pairs of ions in a linear crystal, harnessing the high electric polarizability of highly…

Quantum Physics · Physics 2025-05-01 Han Bao , Jonas Vogel , Ulrich Poschinger , Ferdinand Schmidt-Kaler

We propose a new implementation of a universal set of one- and two-qubit gates for quantum computation using the spin states of coupled single-electron quantum dots. Desired operations are effected by the gating of the tunneling barrier…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 Daniel Loss , David P. DiVincenzo

It is argued that the Aharonov-Casher set up could be used as the basic building block for quantum computation. We demonstrate explicitly in this scenario one- and two-qubit phase shift gates that are fault tolerant to deformations of the…

Quantum Physics · Physics 2016-08-16 Marie Ericsson , Erik Sjöqvist

We perform formal verification of quantum circuits by integrating several techniques specialized to particular classes of circuits. Our verification methodology is based on the new notion of a reversible miter that allows one to leverage…

Quantum Physics · Physics 2013-05-01 Shigeru Yamashita , Igor L. Markov

One-way quantum computing allows any quantum algorithm to be implemented easily using just measurements. The difficult part is creating the universal resource, a cluster state, on which the measurements are made. We propose a radically new…

Quantum Physics · Physics 2008-10-11 Nicolas C. Menicucci , Steven T. Flammia , Olivier Pfister

We report the realization of an elementary quantum processor based on a linear crystal of trapped ions. Each ion serves as a quantum bit (qubit) to store the quantum information in long lived electronic states. We present the realization of…

Coupled Kerr parametric oscillators (KPOs) are a promising resource for classical and quantum analog computation, for example to find the ground state of Ising Hamiltonians. Yet, the state space of strongly coupled KPO networks is very…

Classical Physics · Physics 2025-11-18 Gabriel Margiani , Orjan Ameye , Oded Zilberberg , Alexander Eichler

Quantum computers process information with the laws of quantum mechanics. Current quantum hardware is noisy, can only store information for a short time, and is limited to a few quantum bits, i.e., qubits, typically arranged in a planar…

We show, within the circuit model, how any quantum computation can be efficiently performed using states with only real amplitudes (a result known within the Quantum Turing Machine model). This allows us to identify a 2-qubit (in fact…

Quantum Physics · Physics 2007-05-23 Terry Rudolph , Lov Grover