Quantum Computation

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Tomoyuki Morimae - One of the best experts on this subject based on the ideXlab platform.

  • Arbitrable blind Quantum Computation
    Quantum Information Processing, 2019
    Co-Authors: Go Sato, Takeshi Koshiba, Tomoyuki Morimae
    Abstract:

    Blind Quantum Computation (of a single-server case) is a two-party cryptographic protocol which involves a Quantum Computation server Bob and a client Alice who wants to delegate her Quantum Computation to Bob without revealing her Quantum algorithms and her input to and output from the algorithms. Since Bob may be truant and pretend to execute some Computation, Alice wants to verify Bob’s honesty on Computation. To resolve this problem, the notion of the verifiability has been considered in the literature and several protocols of verifiable blind Computation have been developed. Verifiable blind Quantum Computation enables Alice to check whether Bob is cheating or not. In addition to the above problem, another problem could arise. If Alice pretends to be a client and is actually a competitor against Bob, then she might slander Bob by fabricating his dishonesty. Therefore, if either Alice or Bob is cheating, then a “neutral” referee other than Alice and Bob should judge which is honest. The standard definition of the verifiability guarantees that only Alice can verify Bob’s Computation, and thus, it should be called private verifiability. If Bob claims his innocence though he is actually cheating, then Alice cannot persuade any others that Bob is really cheating while Alice can recognize Bob’s cheating. In this paper, we incorporate arbitrators as the third party into blind Quantum Computation to resolve the above problems and give an arbitrable blind Quantum Computation scheme, which provides public verifiability in some sense.

  • Arbitrable Blind Quantum Computation
    arXiv: Quantum Physics, 2017
    Co-Authors: Go Sato, Takeshi Koshiba, Tomoyuki Morimae
    Abstract:

    Blind Quantum Computation is a two-party protocol which involves a server Bob who has rich Quantum Computational resource and provides Quantum Computation service and a client Alice who wants to delegate her Quantum Computation to Bob without revealing her Quantum algorithms and her input to (resp., output from) the algorithms. Since Bob may be truant and pretend to execute some Computation, Alice wants to verify Bob's Computation. Verifiable blind Quantum Computation enables Alice to check whether Bob is cheating or not. If Bob is cheating and claims his innocence, Alice can refute the denial of Bob's cheating but she cannot persuade any others that Bob is cheating. In this paper, we incorporate arbitrators as the third party into blind Quantum Computation to resolve the above problem and give an arbitrable blind Quantum Computation scheme.

  • Ancilla-driven universal blind Quantum Computation
    Physical Review A - Atomic Molecular and Optical Physics, 2013
    Co-Authors: Takahiro Sueki, Takeshi Koshiba, Tomoyuki Morimae
    Abstract:

    Blind Quantum Computation is a new Quantum secure protocol, which enables Alice who does not have enough Quantum technology to delegate her Computation to Bob who has a fully fledged Quantum power without revealing her input, output, and algorithm. So far, blind Quantum Computation has been considered only for the circuit model and the measurement-based model. Here we consider the possibility and the limitation of blind Quantum Computation in the ancilla-driven model, which is a hybrid of the circuit and the measurement-based models. © 2013 American Physical Society.

  • Blind topological measurement-based Quantum Computation
    Nature Communications, 2012
    Co-Authors: Tomoyuki Morimae, Keisuke Fujii
    Abstract:

    Blind Quantum Computation is a novel secure Quantum-computing protocol that enables Alice, who does not have sufficient Quantum technology at her disposal, to delegate her Quantum Computation to Bob, who has a fully fledged Quantum computer, in such a way that Bob cannot learn anything about Alice's input, output and algorithm. A recent proof-of-principle experiment demonstrating blind Quantum Computation in an optical system has raised new challenges regarding the scalability of blind Quantum Computation in realistic noisy conditions. Here we show that fault-tolerant blind Quantum Computation is possible in a topologically protected manner using the Raussendorf-Harrington-Goyal scheme. The error threshold of our scheme is 4.3 × 10(-3), which is comparable to that (7.5 × 10(-3)) of non-blind topological Quantum Computation. As the error per gate of the order 10(-3) was already achieved in some experimental systems, our result implies that secure cloud Quantum Computation is within reach.

  • Continuous-variable blind Quantum Computation
    Physical Review Letters, 2012
    Co-Authors: Tomoyuki Morimae
    Abstract:

    Blind Quantum Computation is a secure delegated Quantum computing protocol where Alice who does not have sufficient Quantum technology at her disposal delegates her Computation to Bob who has a fully-fledged Quantum computer in such a way that Bob cannot learn anything about Alice's input, output, and algorithm. Protocols of blind Quantum Computation have been proposed for several qubit measurement-based Computation models, such as the graph state model, the Affleck-Kennedy-Lieb-Tasaki model, and the Raussendorf-Harrington-Goyal topological model. Here, we consider blind Quantum Computation for the continuous-variable measurement-based model. We show that blind Quantum Computation is possible for the infinite squeezing case. We also show that the finite squeezing causes no additional problem in the blind setup apart from the one inherent to the continuous-variable measurement-based Quantum Computation.

M Van Den Nest - One of the best experts on this subject based on the ideXlab platform.

  • measurement based Quantum Computation
    Nature Physics, 2009
    Co-Authors: Hans J. Briegel, Dan E Browne, Robert Raussendorf, M Van Den Nest
    Abstract:

    Quantum Computation offers a promising new kind of information processing, where the non-classical features of Quantum mechanics are harnessed and exploited. A number of models of Quantum Computation exist. These models have been shown to be formally equivalent, but their underlying elementary concepts and the requirements for their practical realization can differ significantly. A particularly exciting paradigm is that of measurement-based Quantum Computation, where the processing of Quantum information takes place by rounds of simple measurements on qubits prepared in a highly entangled state. We review recent developments in measurement-based Quantum Computation with a view to both fundamental and practical issues, in particular the power of Quantum Computation, the protection against noise (fault tolerance) and steps towards experimental realization. Finally, we highlight a number of connections between this field and other branches of physics and mathematics. So-called one-way schemes have emerged as a powerful model to describe and implement Quantum Computation. This article reviews recent progress, highlights connections to other areas of physics and discusses future directions.

Hans J. Briegel - One of the best experts on this subject based on the ideXlab platform.

  • Hybrid architecture for encoded measurement-based Quantum Computation
    Scientific Reports, 2014
    Co-Authors: Markus Zwerger, Hans J. Briegel, W. Dür
    Abstract:

    We present a hybrid scheme for Quantum Computation that combines the modular structure of elementary building blocks used in the circuit model with the advantages of a measurement-based approach to Quantum Computation. We show how to construct optimal resource states of minimal size to implement elementary building blocks for encoded Quantum Computation in a measurement-based way, including states for error correction and encoded gates. The performance of the scheme is determined by the quality of the resource states, where within this error model we find a threshold of the order of 10% local noise per particle for fault-tolerant Quantum Computation and Quantum communication.

  • measurement based Quantum Computation
    Nature Physics, 2009
    Co-Authors: Hans J. Briegel, Dan E Browne, Robert Raussendorf, M Van Den Nest
    Abstract:

    Quantum Computation offers a promising new kind of information processing, where the non-classical features of Quantum mechanics are harnessed and exploited. A number of models of Quantum Computation exist. These models have been shown to be formally equivalent, but their underlying elementary concepts and the requirements for their practical realization can differ significantly. A particularly exciting paradigm is that of measurement-based Quantum Computation, where the processing of Quantum information takes place by rounds of simple measurements on qubits prepared in a highly entangled state. We review recent developments in measurement-based Quantum Computation with a view to both fundamental and practical issues, in particular the power of Quantum Computation, the protection against noise (fault tolerance) and steps towards experimental realization. Finally, we highlight a number of connections between this field and other branches of physics and mathematics. So-called one-way schemes have emerged as a powerful model to describe and implement Quantum Computation. This article reviews recent progress, highlights connections to other areas of physics and discusses future directions.

Keisuke Fujii - One of the best experts on this subject based on the ideXlab platform.

  • Quantum Computation with Topological Codes - Quantum Computation with Topological Codes
    SpringerBriefs in Mathematical Physics, 2020
    Co-Authors: Keisuke Fujii
    Abstract:

    This book presents a self-consistent review of Quantum Computation with topological Quantum codes. The book covers everything required to understand topological fault-tolerant Quantum Computation, ranging from the definition of the surface code to topological Quantum error correction and topological fault-tolerant operations. The underlying basic concepts and powerful tools, such as universal Quantum Computation, Quantum algorithms, stabilizer formalism, and measurement-based Quantum Computation, are also introduced in a self-consistent way. The interdisciplinary fields between Quantum information and other fields of physics such as condensed matter physics and statistical physics are also explored in terms of the topological Quantum codes. This book thus provides the first comprehensive description of the whole picture of topological Quantum codes and Quantum Computation with them

  • Topologically Protected Measurement-Based Quantum Computation
    Quantum Computation with Topological Codes, 2015
    Co-Authors: Keisuke Fujii
    Abstract:

    In this chapter, we reformulate topological fault-tolerant Quantum Computation explained in the previous chapter in terms of meausrement-based Quantum Computation.

  • Blind topological measurement-based Quantum Computation
    Nature Communications, 2012
    Co-Authors: Tomoyuki Morimae, Keisuke Fujii
    Abstract:

    Blind Quantum Computation is a novel secure Quantum-computing protocol that enables Alice, who does not have sufficient Quantum technology at her disposal, to delegate her Quantum Computation to Bob, who has a fully fledged Quantum computer, in such a way that Bob cannot learn anything about Alice's input, output and algorithm. A recent proof-of-principle experiment demonstrating blind Quantum Computation in an optical system has raised new challenges regarding the scalability of blind Quantum Computation in realistic noisy conditions. Here we show that fault-tolerant blind Quantum Computation is possible in a topologically protected manner using the Raussendorf-Harrington-Goyal scheme. The error threshold of our scheme is 4.3 × 10(-3), which is comparable to that (7.5 × 10(-3)) of non-blind topological Quantum Computation. As the error per gate of the order 10(-3) was already achieved in some experimental systems, our result implies that secure cloud Quantum Computation is within reach.

Michael A. Nielsen - One of the best experts on this subject based on the ideXlab platform.

  • cluster state Quantum Computation
    Reports on Mathematical Physics, 2006
    Co-Authors: Michael A. Nielsen
    Abstract:

    This article is a short introduction to and review of the cluster-state model of Quantum Computation, in which coherent Quantum information processing is accomplished via a sequence of single-qubit measurements applied to a fixed Quantum state known as a cluster state. We also discuss a few novel properties of the model, including a proof that the cluster state cannot occur as the exact ground state of any naturally occurring physical system, and a proof that measurements on any Quantum state which is linearly prepared in one dimension can be efficiently simulated on a classical computer, and thus are not candidates for use as a substrate for Quantum Computation.

  • Cluster-state Quantum Computation
    Reports on Mathematical Physics, 2006
    Co-Authors: Michael A. Nielsen
    Abstract:

    This article is a short introduction to and review of the cluster-state model of Quantum Computation, in which coherent Quantum information processing is accomplished via a sequence of single-qubit measurements applied to a fixed Quantum state known as a cluster state. We also discuss a few novel properties of the model, including a proof that the cluster state cannot occur as the exact ground state of any naturally occurring physical system, and a proof that measurements on any Quantum state which is linearly prepared in one dimension can be efficiently simulated on a classical computer, and thus are not candidates for use as a substrate for Quantum Computation. © 2006 Polish Scientific Publishers PWN, Warszawa.

  • Optical Quantum Computation using cluster states
    Physical Review Letters, 2004
    Co-Authors: Michael A. Nielsen
    Abstract:

    We propose an approach to optical Quantum Computation in which a deterministic entangling Quantum gate may be performed using, on average, a few hundred coherently interacting optical elements (beamsplitters, phase shifters, single photon sources, and photodetectors with feedforward). This scheme combines ideas from the optical Quantum computing proposal of Knill, Laflamme and Milburn [Nature 409 (6816), 46 (2001)], and the abstract cluster-state model of Quantum Computation proposed by Raussendorf and Briegel [Phys. Rev. Lett. 86, 5188 (2001)].

  • Quantum Computation by measurement and Quantum memory
    Physics Letters A, 2003
    Co-Authors: Michael A. Nielsen
    Abstract:

    What resources are universal for Quantum Computation? In the standard model of a Quantum computer, a Computation consists of a sequence of unitary gates acting coherently on the qubits making up the computer. This requirement for coherent unitary dynamical operations is widely believed to be the critical element of Quantum Computation. Here we show that a very different model involving only projective measurements and Quantum memory is also universal for Quantum Computation. In particular, no coherent unitary dynamics are involved in the Computation. (C) 2003 Elsevier Science B.V. All rights reserved.

  • Theory of Quantum Computation
    arXiv: Quantum Physics, 2000
    Co-Authors: E. Knill, Michael A. Nielsen
    Abstract:

    Short review article on Quantum Computation accepted for Supplement III, Encyclopaedia of Mathematics (publication expected Summer 2001). See also this http URL