Quantum Information and Quantum Control

2005 ◽  
Vol 5 (4&5) ◽  
pp. 723-724
Author(s):  
P. Brumer ◽  
D. Lidar ◽  
H-K Lo ◽  
A. Steinberg
Keyword(s):  
Quantum Information ◽  
Quantum Control

Editorial

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.

The significance of theC-numerical range and the localC-numerical range in quantum control and quantum information

2008 ◽  
Vol 56 (1-2) ◽  
pp. 3-26 ◽  
Author(s):  
Thomas Schulte-herbrüggen ◽  
Gunther Dirr ◽  
Uwe Helmke ◽  
Steffen J. Glaser
Keyword(s):  
Quantum Information ◽  
Quantum Control ◽  
Numerical Range

scholarly journals Genuine quantum networks with superposed tasks and addressing

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
J. Miguel-Ramiro ◽  
A. Pirker ◽  
W. Dür
Keyword(s):  
Quantum Information ◽  
Quantum Control ◽  
Coherent Control ◽  
Quantum Superposition ◽  
Quantum Networks ◽  
Target State

AbstractWe show how to make quantum networks, both standard and entanglement-based, genuine quantum by providing them with the possibility of handling superposed tasks and superposed addressing. This extension of their functionality relies on a quantum control register, which specifies not only the task of the network, but also the corresponding weights in a coherently superposed fashion. Although adding coherent control to classical tasks, such as sending or measuring—or not doing so—is in general impossible, we introduce protocols that are able to mimick this behavior under certain conditions. We achieve this by always performing the classical task, either on the desired state or a properly chosen dummy state. We provide several examples, and show that externally controlling quantum superposition of tasks offers additional possibilities and advantages over usually considered single functionality. For instance, superpositions of different target state configurations shared among different nodes of the network can be prepared, or quantum information can be sent among a superposition of different paths or to different destinations.

scholarly journals Quantum Control and Quantum Information Technology

2013 ◽  
Vol 2013 ◽  
pp. 1-2 ◽  
Author(s):  
Daoyi Dong ◽  
Chunlin Chen ◽  
Min Jiang ◽  
Lin-Cheng Wang
Keyword(s):  
Information Technology ◽  
Quantum Information ◽  
Quantum Control

scholarly journals Quantum control with a multi-dimensional Gaussian quantum invariant

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 409
Author(s):  
Selwyn Simsek ◽  
Florian Mintert
Keyword(s):  
Information Technology ◽  
Quantum Information ◽  
Control Problem ◽  
Ground State ◽  
Quantum Control ◽  
Spatial Dimension ◽  
Time Dependent ◽  
Quantum Invariants ◽  
Quantum Invariant ◽  
Trapped Ion

The framework of quantum invariants is an elegant generalization of adiabatic quantum control to control fields that do not need to change slowly. Due to the unavailability of invariants for systems with more than one spatial dimension, the benefits of this framework have not yet been exploited in multi-dimensional systems. We construct a multi-dimensional Gaussian quantum invariant that permits the design of time-dependent potentials that let the ground state of an initial potential evolve towards the ground state of a final potential. The scope of this framework is demonstrated with the task of shuttling an ion around a corner which is a paradigmatic control problem in achieving scalability of trapped ion quantum information technology.

scholarly journals QUANTUM CONTROL, QUANTUM INFORMATION PROCESSING, AND QUANTUM-LIMITED METROLOGY WITH TRAPPED IONS

2005 ◽  
Author(s):  
D. J. WINELAND ◽  
D. LEIBFRIED ◽  
M. D. BARRETT ◽  
A. BEN-KISH ◽  
J. C. BERGQUIST ◽  
...  
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Control ◽  
Quantum Information Processing ◽  
Trapped Ions
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