Phase control for entanglement preparation in two-qubit systems

2005 ◽  
Vol 5 (4&5) ◽  
pp. 364-379
Author(s):  
V.S. Malinovsky ◽  
I.R. Sola
Keyword(s):  
Quantum Information ◽  
Quantum Computation ◽  
Quantum Control ◽  
Phase Control ◽  
Adiabatic Passage ◽  
Pulse Parameters ◽  
Qubit System ◽  
Phase Manipulation ◽  
Laser Control ◽  
Pi Pulses

The theory of Quantum Control is starting to lay bridges with the field of Quantum Information and Quantum Computation. Using key ideas of laser control of the dynamics by means of phase manipulation and adiabatic passage, we review laser schemes that allow entanglement preparation in a two-qubit system. The schemes are based on sequences that use four time-delayed pulses, with or without concerted decay, in or off resonance with the intermediate levels of the qubit space. We show how to control the fidelity and phase of the entanglement, as well as the sensitivity of the preparation to the different pulse parameters. In general the schemes provide an improvement in robustness and in the finesse of the control to phase, with respect to previously proposed schemes based on sequences of $\pi$ pulses.

scholarly journals CONTROL OF QUANTUM SYSTEMS

2003 ◽  
Vol 17 (28) ◽  
pp. 5397-5411 ◽  
Author(s):  
JOHN W. CLARK ◽  
DENNIS G. LUCARELLI ◽  
TZYH-JONG TARN
Keyword(s):  
Quantum Computation ◽  
Quantum Control ◽  
Sufficient Conditions ◽  
The State ◽  
Dimensional Manifold ◽  
Infinite Dimensional ◽  
Many Body Theory ◽  
Laser Control ◽  
Control Of Quantum Systems ◽  
The Impact

A quantum system subject to external fields is said to be controllable if these fields can be adjusted to guide the state vector to a desired destination in the state space of the system. Fundamental results on controllability are reviewed against the background of recent ideas and advances in two seemingly disparate endeavours: (i) laser control of chemical reactions and (ii) quantum computation. Using Lie-algebraic methods, sufficient conditions have been derived for global controllability on a finite-dimensional manifold of an infinite-dimensional Hilbert space, in the case that the Hamiltonian and control operators, possibly unbounded, possess a common dense domain of analytic vectors. Some simple examples are presented. A synergism between quantum control and quantum computation is creating a host of exciting new opportunities for both activities. The impact of these developments on computational many-body theory could be profound.

QUANTUM CONTROL BASED ON QUANTUM INFORMATION

2007 ◽  
Vol 21 (07) ◽  
pp. 969-977 ◽  
Author(s):  
ZONGHAI CHEN ◽  
CHENBIN ZHANG ◽  
DAOYI DONG
Keyword(s):  
Quantum Information ◽  
Quantum Computation ◽  
Quantum Control ◽  
Quantum Error Correction ◽  
State Recognition ◽  
Quantum Control Theory ◽  
Control Schemes ◽  
Quantum Feedback ◽  
Potential Applications ◽  
Quantum Error

Quantum control strategy is discussed from the perspective of quantum information. First, the constraints imposed on quantum control by quantum theory are analyzed. Then some quantum control schemes based on quantum information are discussed, such as teleportation-based distant quantum control, quantum feedback control using quantum cloning and state recognition, quantum control based on measurement and Grover iteration. Finally, some applications of quantum control theory in quantum information and quantum computation such as quantum error correction coding, universality analysis of quantum computation, feedback-induced entanglement enhancement, etc., are presented and the potential applications of quantum control are also prospected.

INTEGRABILITY, ENTROPY AND QUANTUM COMPUTATION

1999 ◽  
Vol 10 (07) ◽  
pp. 1205-1228 ◽  
Author(s):  
E. V. KRISHNAMURTHY
Keyword(s):  
Quantum Computation ◽  
Quantum Chaos ◽  
Quantum Control ◽  
Dynamical Evolution ◽  
Open Problems ◽  
Quantum Integrability ◽  
Feynman Path Integrals ◽  
Exact Integrability ◽  
Time Arrow ◽  
Computational Systems

The important requirements are stated for the success of quantum computation. These requirements involve coherent preserving Hamiltonians as well as exact integrability of the corresponding Feynman path integrals. Also we explain the role of metric entropy in dynamical evolutionary system and outline some of the open problems in the design of quantum computational systems. Finally, we observe that unless we understand quantum nondemolition measurements, quantum integrability, quantum chaos and the direction of time arrow, the quantum control and computational paradigms will remain elusive and the design of systems based on quantum dynamical evolution may not be feasible.

BOOK REVIEW: "PRINCIPLES OF QUANTUM COMPUTATION AND QUANTUM INFORMATION, Vol. I: BASIC CONCEPTS, VOL. II: BASIC TOOLS AND SPECIAL TOPICS" BY G. BENENTI, G. CASATI AND G. STRINI

2007 ◽  
Vol 05 (06) ◽  
pp. 913-921
Author(s):  
JÁNOS A. BERGOU
Keyword(s):  
Quantum Information ◽  
Quantum Computation ◽  
Current Literature ◽  
Reference Book ◽  
Introductory Course ◽  
Basic Concepts

This two-volume book is a great addition to the growing number of books devoted to the field. It is very clearly written by classroom professionals, always with the students in mind. The tutorial presentation is supplemented with a number of exercises whose solutions are also given at the end of each volume. The first volume can serve as a textbook for a one semester introductory course in quantum computation and quantum information. The second volume is more technical and brings the reader to the level of the current literature. It is useful for the specialist, can serve as a textbook for a more advanced course, or has its place as a reference book. In summary, I can highly recommend this book to anyone interested in this field.

scholarly journals Holistic logical arguments in quantum computation

2016 ◽  
Vol 66 (2) ◽  
Author(s):  
Maria Luisa Dalla Chiara ◽  
Roberto Giuntini ◽  
Roberto Leporini ◽  
Giuseppe Sergioli
Keyword(s):  
Quantum Information ◽  
Quantum Computation ◽  
Essential Role ◽  
Circuit Theory ◽  
Logical Connectives ◽  
Quantum Computational Logics

AbstractQuantum computational logics represent a logical abstraction from the circuit-theory in quantum computation. In these logics formulas are supposed to denote pieces of quantum information (qubits, quregisters or mixtures of quregisters), while logical connectives correspond to (quantum logical) gates that transform quantum information in a reversible way. The characteristic holistic features of the quantum theoretic formalism (which play an essential role in entanglement-phenomena) can be used in order to develop a

scholarly journals Rydberg-interaction gates via adiabatic passage and phase control of driving fields

2017 ◽  
Vol 96 (2) ◽  
Author(s):  
Huaizhi Wu ◽  
Xi-Rong Huang ◽  
Chang-Sheng Hu ◽  
Zhen-Biao Yang ◽  
Shi-Biao Zheng
Keyword(s):  
Phase Control ◽  
Adiabatic Passage

EFFICIENT ALGORITHM FOR INITIALIZING AMPLITUDE DISTRIBUTION OF A QUANTUM REGISTER

2001 ◽  
Vol 15 (27) ◽  
pp. 1259-1264 ◽  
Author(s):  
M. ANDRECUT ◽  
M. K. ALI
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Computation ◽  
Quantum State ◽  
Efficient Algorithm ◽  
Quantum Information Processing ◽  
Amplitude Distribution ◽  
Quantum Register

The preparation of a quantum register in an arbitrary superposed quantum state is an important operation for quantum computation and quantum information processing. Here, we present an efficient algorithm which requires a polynomial number of elementary operations for initializing the amplitude distribution of a quantum register.

scholarly journals Quantum Switchboard with Coupled-Cavity Array

2021 ◽  
Author(s):  
Wai-Keong Mok ◽  
Leong-Chuan Kwek
Keyword(s):  
Quantum Information ◽  
Quantum Computation ◽  
Scaling Up ◽  
Quantum Network ◽  
Quantum Cloning ◽  
Physical Implementation ◽  
Large Quantum ◽  
Coupled Cavity ◽  
Cavity Array

The ability to control the flow of quantum information deterministically is useful for scaling up quantum computation. In this paper, we demonstrate a controllable quantum switchboard which directs the teleportation protocol to one of two targets, fully dependent on the sender’s choice. The quantum switchboard additionally acts as a optimal quantum cloning machine. We also provide a physical implementation of the proposal using a coupled-cavity array. The proposed switchboard can be utilized for the efficient routing of quantum information in a large quantum network.

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