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We show a perfect state transfer of an arbitrary unknown two-qubit state can be achieved via a discrete-time quantum walk with various settings of coin flippings, and extend this method to distribution of an arbitrary unknown multi-qubit…

Quantum Physics · Physics 2014-07-23 Xiang Zhan , Hao Qin , Zhi-hao Bian , Jian Li , Peng Xue

We demonstrate a scheme for controlling a large quantum system by acting on a small subsystem only. The local control is mediated to the larger system by some fixed coupling Hamiltonian. The scheme allows to transfer arbitrary and unknown…

Quantum Physics · Physics 2007-09-05 Daniel Burgarth , Vittorio Giovannetti

Uhlmann's theorem is a central result in quantum information theory, which associates the closeness of two quantum states with that of their purifications. The theorem also well characterizes a fundamental task: how close a pure quantum…

Quantum Physics · Physics 2025-11-04 Takeru Utsumi , Yoshifumi Nakata , Qisheng Wang , Ryuji Takagi

In this article we describe a technique to transfer data from classical domain to quantum domain. We consider a set of $N (=2^n)$ classical data in the form of a column matrix and prepare a $n$-qubit quantum state, whose components…

Quantum Physics · Physics 2021-07-21 Kumar Ghosh

Distributed quantum computing combines the computational power of multiple devices to overcome the limitations of individual devices. Circuit cutting techniques enable the distribution of quantum computations through classical…

Quantum Physics · Physics 2023-06-22 Marvin Bechtold , Johanna Barzen , Frank Leymann , Alexander Mandl

Recently bidirectional controlled perfect teleportation using 5-qubit states are reported in (Int. J. Theor. Phys. (2013) DOI 10.1007/s10773-013-1484-8 and ibid, (2013) DOI 10.1007/s10773-012-1208-5). In this paper we have shown that there…

Quantum Physics · Physics 2015-06-15 Chitra Shukla , Anindita Banerjee , Anirban Pathak

The well-known Schmidt decomposition, or equivalently, the complex singular value decomposition, states that a pure quantum state of a bipartite system can always be brought into a "diagonal" form using local unitary transformations. In…

Quantum Physics · Physics 2024-01-17 Emanuel Malvetti

Probabilistic quantum state transformations can be characterized by the degree of state separation they provide. This, in turn, sets limits on the success rate of these transformations. We consider optimum state separation of two known pure…

Quantum Physics · Physics 2016-01-20 Emilio Bagan , Vadim Yerokhin , Andi Shehu , Edgar Feldman , Janos A. Bergou

We present a fast scheme for arbitrary unitary control of interacting bosonic atoms in a double-well. Assuming fixed inter-well tunnelling rate and intra-well interaction strength, we control the many-atom state by a discrete sequence of…

Quantum Physics · Physics 2013-06-26 Malte C. Tichy , Mads Kock Pedersen , Klaus Mølmer , Jacob F. Sherson

A quantum computer based on an asymmetric coupled dot system has been proposed and shown to operate as the controlled-NOT-gate. The basic idea is (1) the electron is localized in one of the asymmetric coupled dots. (2)The electron transfer…

Quantum Physics · Physics 2008-12-18 Tetsufumi Tanamoto

We consider stochastic and open quantum systems with a finite number of states, where a stochastic transition between two specific states is monitored by a detector. The long-time counting statistics of the observed realizations of the…

Quantum Physics · Physics 2014-03-27 M. Bruderer , L. D. Contreras-Pulido , M. Thaller , L. Sironi , D. Obreschkow , M. B. Plenio

As a variant of the original quantum teleportation, the port-based teleportation has been proposed, and its various kinds of useful applications in quantum information processing have been explored. Two users in the port-based teleportation…

Quantum Physics · Physics 2020-07-14 Kabgyun Jeong , Jaewan Kim , Soojoon Lee

We propose and investigate a method to optimize recurrence entanglement purification protocols. The approach is based on a numerical search in the whole set of SU(4) matrices with the aid of a quasi-Newton algorithm. Our method evaluates…

Quantum Physics · Physics 2024-04-17 Francesco Preti , Tommaso Calarco , Juan Mauricio Torres , József Zsolt Bernád

The recently derived input-output relations for the radiation field at a dispersive and absorbing four-port device [T. Gruner and D.-G. Welsch, Phys. Rev. A 54, 1661 (1996)] are used to derive the unitary transformation that relates the…

Quantum Physics · Physics 2009-10-31 L. Knoell , S. Scheel , E. Schmidt , D. -G. Welsch

Most quantum processors requires pulse sequences for controlling quantum states. Here, we present an alternative algorithm for computing an optimal pulse sequence in order to perform a specific task, being an implementation of a quantum…

Quantum Physics · Physics 2020-05-27 John P. S. Peterson , Roberto S. Sarthour , Raymond Laflamme

We present a method for optimizing quantum control in experimental systems, using a subset of randomized benchmarking measurements to rapidly infer error. This is demonstrated to improve single- and two-qubit gates, minimize gate…

Quantum simulators, machines that can replicate the dynamics of quantum systems, are being built as useful devices and are seen as a stepping stone to universal quantum computers. A key difference between the two is that computers have the…

Quantum Physics · Physics 2018-08-09 Benjamin Dive , Alexander Pitchford , Florian Mintert , Daniel Burgarth

The orbit tracking of free-evolutionary target system in closed quantum systems is studied in this paper. Based on the concept of system control theory, the unitary transformation is applied to change the time-dependent target function into…

Mathematical Physics · Physics 2018-08-10 Shuang Cong , Jianxiu Liu , Fei Yang

At present, several models for quantum computation have been proposed. Adiabatic quantum computation scheme particularly offers this possibility and is based on a slow enough time evolution of the system, where no transitions take place. In…

Quantum Physics · Physics 2012-10-12 P. J. Salas Peralta

Quantum computing can be realized with numerous different hardware platforms and computational protocols. A highly promising approach to foster scalability is to apply a photonic platform combined with a measurement-induced quantum…