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Related papers: Implementing quantum logic operations, pseudo-pure…

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Since the first demonstration of coherent control of a quantum state of a superconducting charge qubit a variety of Josephson-junction-based qubits have been implemented with remarkable progress in coherence time and read-out schemes.…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 T. Yamamoto , Yu. A. Pashkin , O. Astafiev , Y. Nakamura , J. S. Tsai

We calculate the propagator and the transition probabilities for a coherently driven three-state quantum system. The energies of the three states change linearly in time, whereas the interactions between them are pulse-shaped. We derive a…

Quantum Physics · Physics 2009-11-13 S. S. Ivanov , N. V. Vitanov

We proposed a scheme to realize a controlled-NOT quantum logic gate in a dimer of exchange coupled single-molecule magnets, $[\textrm{Mn}_4]_2$. We chosen the ground state and the three low-lying excited states of a dimer in a finite…

Quantum Physics · Physics 2015-06-26 Jing-Min Hou , Li-Jun Tian , Mo-lin Ge

The development of efficient algorithms that generate robust quantum controls is crucial for the realization of quantum technologies. The commonly used gradient-based optimization algorithms are limited by their sensitivity to the initial…

Quantum Physics · Physics 2021-12-03 M. Harshanth Ram , V. R. Krithika , Priya Batra , T. S. Mahesh

We present a genetic algorithm for finding a set of pulse sequences, or rotations, for a given quantum logic gate, as implemented by NMR. We demonstrate the utility of the method by showing that shorter sequences than have been previously…

Quantum Physics · Physics 2012-07-31 M. J. Rethinam , A. K. Javali , E. C. Behrman , J. E. Steck , S. R. Skinner

The preparation of pseudo-pure states plays a central role in the implementation of quantum information processing in high temperature ensemble systems, such as nuclear magnetic resonance. Here we describe a simple approach based on…

Quantum Physics · Physics 2010-09-21 Minaru Kawamura , Benjamin Rowland , Jonathan A. Jones

We report successful manipulation of non-classical atomic spin states. We generate squeezed spin states by a spin quantum nondemolition measurement, and apply an off-resonant circularly-polarized light pulse to the atoms. By changing the…

Quantum Physics · Physics 2015-05-14 Tetsushi Takano , Shin-Ichi-Ro Tanaka , Ryo Namiki , Yoshiro Takahashi

We have taken significant steps towards the realization of a practical quantum computer: using nuclear spins and magnetic resonance techniques at room temperature, we provided proof of principle of quantum computing in a series of…

Quantum Physics · Physics 2009-09-29 Lieven M. K. Vandersypen

Systematic errors in spin rotation operations using simple RF pulses place severe limitations on the usefulness of the pulsed magnetic resonance methods in quantum computing applications. In particular, the fidelity of quantum logic…

We demonstrate how NMR can in principle be used to implement all the elements required to build quantum computers, and briefly discuss the potential applications of insights from quantum logic to the development of novel pulse sequences…

Quantum Physics · Physics 2009-10-31 J. A. Jones , R. H. Hansen , M. Mosca

We propose and demonstrate a quantum control scheme for hybrid quantum registers that can reduce the operation time, and therefore the effects of relaxation, compared to existing implementations. It combines resonant excitation pulses with…

Quantum Physics · Physics 2018-10-10 Jingfu Zhang , Swathi S Hegde , Dieter Suter

We present a continuous-time, neural-network-based approach to optimal control in quantum systems, with a focus on pulse engineering for quantum gates. Leveraging the framework of neural ordinary differential equations, we construct control…

Quantum computers can solve certain problems more efficiently than any possible conventional computer. Small quantum algorithms have been demonstrated on multiple quantum computing platforms, many specifically tailored in hardware to…

Quantum Physics · Physics 2016-08-05 S. Debnath , N. M. Linke , C. Figgatt , K. A. Landsman , K. Wright , C. Monroe

Implementing quantum algorithms is essential for quantum computation. We study the implementation of three quantum algorithms by performing homodyne measurements on a two-dimensional temporal continuous-variable cluster state. We first…

The prospect of building quantum circuits using advanced semiconductor manufacturing positions quantum dots as an attractive platform for quantum information processing. Extensive studies on various materials have led to demonstrations of…

Mesoscale and Nanoscale Physics · Physics 2021-04-14 N. W. Hendrickx , W. I. L. Lawrie , M. Russ , F. van Riggelen , S. L. de Snoo , R. N. Schouten , A. Sammak , G. Scappucci , M. Veldhorst

We present an original model of paraconsistent Turing machines (PTMs), a generalization of the classical Turing machines model of computation using a paraconsistent logic. Next, we briefl y describe the standard models of quantum…

Quantum Physics · Physics 2007-05-23 Juan C. Agudelo , Walter Carnielli

We describe in detail the application of four qubit cluster states, built on the simultaneous entanglement of two photons in the degrees of freedom of polarization and linear momentum, for the realization of a complete set of basic one-way…

Quantum Physics · Physics 2008-11-05 Giuseppe Vallone , Enrico Pomarico , Francesco De Martini , Paolo Mataloni

Quantum information processing by liquid-state NMR spectroscopy uses pseudo-pure states to mimic the evolution and observations on true pure states. A new method of preparing pseudo-pure states is described, which involves the selection of…

Quantum Physics · Physics 2009-11-06 Yehuda Sharf , Timothy F. Havel , David G. Cory

We present a method of using a nuclear magnetic resonance computer to solve the Deutsch-Jozsa problem in which: (1) the number of molecules in the NMR sample is irrelevant to the number of qubits available to an NMR quantum computer, and…

Quantum Physics · Physics 2009-11-13 Amr F. Fahmy , Raimund Marx , Wolfgang Bermel , Steffen J. Glaser

High-fidelity control of quantum systems is essential for scalable quantum technologies. We introduce a shooting-based method which yields smooth control pulses designed to implement gates on discrete quantum systems, and demonstrate its…

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