The Experts below are selected from a list of 5124 Experts worldwide ranked by ideXlab platform
Mio Murao - One of the best experts on this subject based on the ideXlab platform.
-
Reversing Unknown Quantum Transformations: Universal Quantum Circuit for Inverting General Unitary Operations.
Physical review letters, 2019Co-Authors: Marco Túlio Quintino, Akihito Soeda, Qingxiuxiong Dong, Atsushi Shimbo, Mio MuraoAbstract:Given a quantum gate implementing a $d$-dimensional Unitary Operation ${U}_{d}$, without any specific description but $d$, and permitted to use $k$ times, we present a universal probabilistic heralded quantum circuit that implements the exact inverse ${U}_{d}^{\ensuremath{-}1}$, whose failure probability decays exponentially in $k$. The protocol employs an adaptive strategy, proven necessary for the exponential performance. It requires that $k\ensuremath{\ge}d\ensuremath{-}1$, proven necessary for the exact implementation of ${U}_{d}^{\ensuremath{-}1}$ with quantum circuits. Moreover, even when quantum circuits with indefinite causal order are allowed, $k\ensuremath{\ge}d\ensuremath{-}1$ uses are required. We then present a finite set of linear and positive semidefinite constraints characterizing universal Unitary inversion protocols and formulate a convex optimization problem whose solution is the maximum success probability for given $k$ and $d$. The optimal values are computed using semidefinite programing solvers for $k\ensuremath{\le}3$ when $d=2$ and $k\ensuremath{\le}2$ for $d=3$. With this numerical approach we show for the first time that indefinite causal order circuits provide an advantage over causally ordered ones in a task involving multiple uses of the same Unitary Operation.
-
Complex conjugation supermap of Unitary quantum maps and its universal implementation protocol
Physical Review Research, 2019Co-Authors: Jisho Miyazaki, Akihito Soeda, Mio MuraoAbstract:A complex conjugation of Unitary quantum map is a second-order map (supermap) that maps a Unitary operator $U$ to its complex conjugate $U^*$. First, we present a deterministic quantum protocol that universally implements the complex conjugation supermap when we are given a blackbox quantum circuit, guaranteed to implement some Unitary Operation, whose only known description is its dimension. We then discuss the complex conjugation supermap in the context of entanglement theory and derive a conjugation-based expression of the $G$-concurrence. Finally, we present a physical process involving identical fermions from which the complex conjugation protocol is derived as a simulation of the process using qudits.
-
Network Coding for Distributed Quantum Computation Over Cluster and Butterfly Networks
IEEE Transactions on Information Theory, 2016Co-Authors: Seiseki Akibue, Mio MuraoAbstract:To apply network coding for quantum computation , we study the distributed implementation of Unitary Operations over all separated input and output nodes of quantum networks. We consider networks where quantum communication between nodes is restricted to sending a qubit, but classical communication is unrestricted. We analyze which $N$ -qubit Unitary Operations are implementable over cluster networks by investigating transformations of a given cluster network into quantum circuits. We show that any two-qubit Unitary Operation is implementable over the butterfly network and the grail network , which are fundamental primitive networks for classical network coding. We also analyze probabilistic implementations of Unitary Operations over cluster networks.
-
Universal implementation of projective measurement of energy
arXiv: Quantum Physics, 2013Co-Authors: Shojun Nakayama, Akihito Soeda, Mio MuraoAbstract:We present a scheme to asymptotically implement a projective measurement in the energy eigenbasis on a finite dimensional system driven by an unknown Hamiltonian $H$ based on the quantum phase estimation algorithm. Our scheme also provides an outcome associated with an energy eigenvalue of $H$. Two new algorithms are introduced to apply the quantum phase estimation algorithms for unknown Hamiltonian systems. One is for asymptotically but universally implementing a controlled Unitary Operation $C_{U(t)}$ of a Unitary Operation $U(t)=e^{-iHt}$ up to the global phase of $U(t)$ for an unknown Hamiltonian $H$. This algorithm utilizes random Unitary Operations achieve a decoupling effect. The other is an algorithm for evaluating the absolute value of the trace of $U(t)$ without using $C_{U(t)}$ required to run the first algorithm. We analyze the accuracy and the running time of our scheme and show that the running time of our scheme is independent of the dimension of the system for a given accuracy.
-
Delocalization power of global Unitary Operations on quantum information
New Journal of Physics, 2010Co-Authors: Akihito Soeda, Mio MuraoAbstract:We investigate how originally localized two pieces of quantum information represented by a tensor product of two unknown qudit states are delocalized by performing two-qudit global Unitary Operations. To characterize the delocalization power of global Unitary Operations on quantum information, we analyze the necessary and sufficient condition to deterministically relocalize one of the two pieces of quantum information to its original Hilbert space by using only LOCC. We prove that this LOCC one-piece relocalization is possible if and only if the global Unitary Operation is local Unitary equivalent to a controlled-Unitary Operation. The delocalization power and the entangling power characterize different non-local properties of global Unitary Operations.
Brian J Smith - One of the best experts on this subject based on the ideXlab platform.
-
spectral shearing of quantum light pulses by electro optic phase modulation
Physical Review Letters, 2017Co-Authors: Laura J Wright, Michal Karpinski, Christoph Soller, Brian J SmithAbstract:: Frequency conversion of nonclassical light enables robust encoding of quantum information based upon spectral multiplexing that is particularly well-suited to integrated-optics platforms. Here we present an intrinsically deterministic linear-optics approach to spectral shearing of quantum light pulses and show it preserves the wave-packet coherence and quantum nature of light. The technique is based upon an electro-optic Doppler shift to implement frequency shear of heralded single-photon wave packets by ±200 GHz, which can be scaled to an arbitrary shift. These results demonstrate a reconfigurable method to controlling the spectral-temporal mode structure of quantum light that could achieve Unitary Operation.
-
spectral shearing of quantum light pulses by electro optic phase modulation
Physical Review Letters, 2017Co-Authors: Laura J Wright, Michal Karpinski, Christoph Soller, Brian J SmithAbstract:Frequency conversion of nonclassical light enables robust encoding of quantum information based upon spectral multiplexing that is particularly well-suited to integrated-optics platforms. Here we present an intrinsically deterministic linear-optics approach to spectral shearing of quantum light pulses and show it preserves the wave-packet coherence and quantum nature of light. The technique is based upon an electro-optic Doppler shift to implement frequency shear of heralded single-photon wave packets by $\ifmmode\pm\else\textpm\fi{}200\text{ }\text{ }\mathrm{GHz}$, which can be scaled to an arbitrary shift. These results demonstrate a reconfigurable method to controlling the spectral-temporal mode structure of quantum light that could achieve Unitary Operation.
Mingsheng Ying - One of the best experts on this subject based on the ideXlab platform.
-
Optimal simulation of a perfect entangler
Physical Review A, 2010Co-Authors: Runyao Duan, Mingsheng YingAbstract:A $2\ensuremath{\bigotimes}2$ Unitary Operation is called a perfect entangler if it can generate a maximally entangled state from some unentangled input. We study the following question: How many runs of a given two-qubit entangling Unitary Operation are required to simulate some perfect entangler with one-qubit Unitary Operations as free resources? We completely solve this problem by presenting an analytical formula for the optimal number of runs of the entangling Operation. Our result reveals an entanglement strength of two-qubit Unitary Operations.
-
Local distinguishability of multipartite Unitary Operations.
Physical review letters, 2008Co-Authors: Runyao Duan, Yuan Feng, Mingsheng YingAbstract:We show that any two different Unitary Operations acting on an arbitrary multipartite quantum system can be perfectly distinguished by local Operations and classical communication when a finite number of runs is allowed. Intuitively, this result indicates that the lost identity of a nonlocal Unitary Operation can be recovered locally. No entanglement between distant parties is required.
-
Entanglement is not necessary for perfect discrimination between Unitary Operations.
Physical review letters, 2007Co-Authors: Runyao Duan, Yuan Feng, Mingsheng YingAbstract:We show that a Unitary Operation (quantum circuit) secretly chosen from a finite set of Unitary Operations can be determined with certainty by sequentially applying only a finite amount of runs of the unknown circuit. No entanglement or joint quantum Operations are required in our scheme. We further show that our scheme is optimal in the sense that the number of the runs is minimal when discriminating only two Unitary Operations.
Martin B. Plenio - One of the best experts on this subject based on the ideXlab platform.
-
Quantum Remote Control: Teleportation of Unitary Operations
Physical Review A, 2001Co-Authors: Susana F. Huelga, John A. Vaccaro, Anthony Chefles, Martin B. PlenioAbstract:We consider the implementation of an arbitrary Unitary Operation U upon a distant quantum system. This teleportation of U can be viewed as quantum remote control. We investigate protocols that achieve this using local Operations, classical communication, and shared entanglement. Lower bounds on the necessary entanglement and classical communication are determined using causality and the linearity of quantum mechanics. We examine in particular detail the resources required if the remote control is to be implemented as a classical black box. Under these circumstances, we prove that the required resources are, necessarily, those needed for implementation by bidirectional state teleportation.
Qiaoyan Kang - One of the best experts on this subject based on the ideXlab platform.
-
Remote preparation of an arbitrary multi-qubit state via two-qubit entangled states
Quantum Information Processing, 2017Co-Authors: Jiahua Wei, Lei Shi, Yang Xue, Xuchun Zhuang, Qiaoyan KangAbstract:We propose a novel scheme for remote preparation of an arbitrary n-qubit state with the aid of an appropriate local \(2^n\times 2^n\) Unitary Operation and n maximally entangled two-qubit states. The analytical expression of local Unitary Operation, which is constructed in the form of iterative process, is presented for the preparation of n-qubit state in detail. We obtain the total successful probabilities of the scheme in the general and special cases, respectively. The feasibility of our scheme in preparing remotely multi-qubit states is explicitly demonstrated by theoretical studies and concrete examples, and our results show that the novel proposal could enlarge the applied range of remote state preparation.
