Learning from evaluation: A conversation with Hallie Preskill

Preskill, Hallie; Martineau, Jennifer

doi:10.1002/lia.1045

Cited by 44 publications

(75 citation statements)

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“…The technique uses selective excitation of subsystems, and is easily scalable to higher qubit systems provided the spectrum is well resolved. Since the non-adiabatic geometric phase does not depend on the details of the path traversed, it is insusceptible to certain errors yielding inherently fault-tolerant quantum computation [45,46]. The controlled geometric phase gates were also used to implement DJ-algorithm and Grover's search algorithm in a two-qubit system.…”

Section: Discussionmentioning

confidence: 99%

Use of non-adiabatic geometric phase for quantum computing by NMR

Das

Kumar

2005

Journal of Magnetic Resonance

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Geometric phases have stimulated researchers for its potential applications in many areas of science. One of them is fault-tolerant quantum computation. A preliminary requisite of quantum computation is the implementation of controlled logic gates by controlled dynamics of qubits. In controlled dynamics, one qubit undergoes coherent evolution and acquires appropriate phase, depending on the state of other qubits. If the evolution is geometric, then the phase acquired depend only on the geometry of the path executed, and is robust against certain types of errors. This phenomenon leads to an inherently fault-tolerant quantum computation. Here we suggest a technique of using non-adiabatic geometric phase for quantum computation, using selective excitation. In a two-qubit system, we selectively evolve a suitable subsystem where the control qubit is in state |1 , through a closed circuit. By this evolution, the target qubit gains a phase controlled by the state of the control qubit. Using these geometric phase gates we demonstrate implementation of Deutsch-Jozsa algorithm and Grover's search algorithm in a two-qubit system.

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Section: Discussionmentioning

confidence: 99%

Use of non-adiabatic geometric phase for quantum computing by NMR

Das

Kumar

2005

Journal of Magnetic Resonance

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“…For much more detail, the reader may consult, for instance, Refs. [23][24][25][26]. First of all, we assume that the theory has a finite number of topological sectors, labeled by some finite set of labels.…”

Section: A Fusion Rules Spin and Monodromymentioning

confidence: 99%

Condensate-induced transitions between topologically ordered phases

2009

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We investigate transitions between topologically ordered phases in two spatial dimensions induced by the condensation of a bosonic quasiparticle. To this end, we formulate an extension of the theory of symmetrybreaking phase transitions which applies to phases with topological excitations described by quantum groups or modular tensor categories. This enables us to deal with phases whose quasiparticles have noninteger quantum dimensions and obey braid statistics. Many examples of such phases can be constructed from two-dimensional rational conformal field theories, and we find that there is a beautiful connection between quantum group symmetry breaking and certain well-known constructions in conformal field theory, notably the coset construction, the construction of orbifold models, and more general conformal extensions. Besides the general framework, many representative examples are worked out in detail.

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“…Control of quantum processes [1] such as quantum storage in open quantum system [2] collects a number of separate concepts, and has a variety of manifestations in different areas of physics [3,4]. Quantum storage is concerned with a quantum state stored in open systems in presence of leakage [5] and diffusion processes induced by either the system-environment interaction or inner-coupling between the target storage subspace and the rest of the system space.…”

Section: Introductionmentioning

confidence: 99%

Overview of quantum memory protection and adiabaticity induction by fast signal control

Jing

2015

Science Bulletin

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A quantum memory or information processing device is subject to disturbance from its surrounding environment or inevitable leakage due to its contact with other systems. To tackle these problems, several control protocols have been proposed for quantum memory or storage. Among them, the fast-signal control or dynamical decoupling based on external pulse sequences provides a prevailing strategy aimed at suppressing decoherence and preventing the target systems from the leakage or diffusion process. In this paper, we review the applications of this protocol in protecting quantum memory under the non-Markovian dissipative noise and maintaining systems on finite speed adiabatic passages without leakage therefrom. We analyze leakage and control perturbative and nonperturbative dynamical equations including second-order master equation, quantum-state-diffusion equation, and one-component master equation derived from Feshbach PQ-partitioning technique. It turns out that the quality of fast-modulated signal control is insensitive to configurations of the applied pulse sequences. Specifically, decoherence and leakage will be greatly suppressed as long as the control sequence is able to effectively shift the system beyond the bath cutoff frequency, almost independent of the details of the control sequences which could be ideal pulses, regular rectangular pulses, random pulses and even noisy pulses.

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Learning from evaluation: A conversation with Hallie Preskill

Cited by 44 publications

References 0 publications

Use of non-adiabatic geometric phase for quantum computing by NMR

Use of non-adiabatic geometric phase for quantum computing by NMR

Condensate-induced transitions between topologically ordered phases

Overview of quantum memory protection and adiabaticity induction by fast signal control

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