scholarly journals Quantum information processing with quantum zeno many-body dynamics

2010 ◽  
Vol 10 (3&4) ◽  
pp. 201-222
Author(s):  
A. Monras ◽  
O. Romero-Isart
Keyword(s):  
Quantum Information ◽  
Quantum Information Processing ◽  
Quantum Zeno Effect ◽  
Quantum State Transfer ◽  
Many Body ◽  
One Dimensional ◽  
Zeno Effect ◽  
State Transfer ◽  
Body Dynamics ◽  
Universal Quantum

We show how the quantum Zeno effect can be exploited to control quantum many-body dynamics for quantum information and computation purposes. In particular, we consider a one dimensional array of three level systems interacting via a nearest-neighbour interaction. By encoding the qubit on two levels and using simple projective frequent measurements yielding the quantum Zeno effect, we demonstrate how to implement a well defined quantum register, quantum state transfer on demand, universal two-qubit gates and two-qubit parity measurements. Thus, we argue that the main ingredients for universal quantum computation can be achieved in a spin chain with an {\em always-on} and {\em constant} many-body Hamiltonian. We also show some possible modifications of the initially assumed dynamics in order to create maximally entangled qubit pairs and single qubit gates.

QUANTUM INFORMATION PROCESSING IN AN ARRAY OF SUPERCONDUCTING TRANSMISSION LINE RESONATORS

2009 ◽  
Vol 07 (06) ◽  
pp. 1255-1267
Author(s):  
JIAN LI ◽  
JIAN ZOU ◽  
BIN SHAO
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Transmission Line ◽  
Quantum State ◽  
Quantum Information Processing ◽  
Quantum State Transfer ◽  
Superconducting Qubit ◽  
One Dimensional ◽  
Dimensional Array ◽  
State Transfer

We consider a one-dimensional array of superconducting transmission line resonators (TLRs). The TLRs are coupled by current-biased Josephson junctions, which act as tunable couplers between each two nearest TLRs, and a superconducting qubit is fabricated in the center of each TLR. We show that some important quantum information processing, such as quantum state transfer and preparation of remote entanglement, can be achieved in this system, and we also propose a scheme for generating the W-class states.

scholarly journals Quantum networks: topology and spectral characterization

2018 ◽  
Vol 182 ◽  
pp. 02014
Author(s):  
Vesna Berec
Keyword(s):  
Quantum Information Processing ◽  
Theoretic Approach ◽  
Quantum State Transfer ◽  
Complexity Measures ◽  
Quantum Networks ◽  
Graph Theoretic ◽  
Topological Features ◽  
State Transfer ◽  
Quantum Complexity ◽  
And Control

To utilize a scalable quantum network and perform a quantum state transfer within distant arbitrary nodes, coherence and control of the dynamics of couplings between the information units must be achieved as a prerequisite ingredient for quantum information processing within a hierarchical structure. Graph theoretic approach provides a powerful tool for the characterization of quantum networks with non-trivial clustering properties. By encoding the topological features of the underlying quantum graphs, relations between the quantum complexity measures are presented revealing the intricate links between a quantum and a classical networks dynamics.

scholarly journals Non-Hermitian fractional quantum Hall states

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tsuneya Yoshida ◽  
Koji Kudo ◽  
Yasuhiro Hatsugai
Keyword(s):  
Ground State ◽  
Cold Atoms ◽  
Quantum Hall ◽  
Quantum Zeno Effect ◽  
Many Body ◽  
Fractional Quantum ◽  
Fractional Quantum Hall ◽  
Zeno Effect ◽  
Quantum Hall States ◽  
The Many

AbstractWe demonstrate the emergence of a topological ordered phase for non-Hermitian systems. Specifically, we elucidate that systems with non-Hermitian two-body interactions show a fractional quantum Hall (FQH) state. The non-Hermitian Hamiltonian is considered to be relevant to cold atoms with dissipation. We conclude the emergence of the non-Hermitian FQH state by the presence of the topological degeneracy and by the many-body Chern number for the ground state multiplet showing Ctot = 1. The robust topological degeneracy against non-Hermiticity arises from the manybody translational symmetry. Furthermore, we discover that the FQH state emerges without any repulsive interactions, which is attributed to a phenomenon reminiscent of the continuous quantum Zeno effect.

scholarly journals Ultracold quantum wires with localized losses: Many-body quantum Zeno effect

2020 ◽  
Vol 101 (14) ◽  
Author(s):  
Heinrich Fröml ◽  
Christopher Muckel ◽  
Corinna Kollath ◽  
Alessio Chiocchetta ◽  
Sebastian Diehl
Keyword(s):  
Quantum Wires ◽  
Quantum Zeno Effect ◽  
Many Body ◽  
Zeno Effect

scholarly journals Many-Body Quantum Zeno Effect and Measurement-Induced Subradiance Transition

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 528
Author(s):  
Alberto Biella ◽  
Marco Schiró
Keyword(s):  
Continuous Monitoring ◽  
Transverse Field ◽  
Body System ◽  
Ising Chain ◽  
Quantum Zeno Effect ◽  
Many Body ◽  
Unitary Evolution ◽  
Zeno Effect ◽  
Quantum Ising Model ◽  
Sharp Phase Transition

It is well known that by repeatedly measuring a quantum system it is possible to completely freeze its dynamics into a well defined state, a signature of the quantum Zeno effect. Here we show that for a many-body system evolving under competing unitary evolution and variable-strength measurements the onset of the Zeno effect takes the form of a sharp phase transition. Using the Quantum Ising chain with continuous monitoring of the transverse magnetization as paradigmatic example we show that for weak measurements the entanglement produced by the unitary dynamics remains protected, and actually enhanced by the monitoring, while only above a certain threshold the system is sharply brought into an uncorrelated Zeno state. We show that this transition is invisible to the average dynamics, but encoded in the rare fluctuations of the stochastic measurement process, which we show to be perfectly captured by a non-Hermitian Hamiltonian which takes the form of a Quantum Ising model in an imaginary valued transverse field. We provide analytical results based on the fermionization of the non-Hermitian Hamiltonian in supports of our exact numerical calculations.

Non-local universal gates generated within a resonant magnetic cavity

2018 ◽  
Vol 18 (13&14) ◽  
pp. 1081-1094
Author(s):  
Francisco Delgado
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Information Processing ◽  
Complex Dynamics ◽  
Time Dependent ◽  
Quantum Evolution ◽  
Basic Block ◽  
Precise Control ◽  
Universal Quantum ◽  
Set Up

Quantum Information is a quantum resource being advised as a useful tool to set up information processing. Despite physical components being considered are normally two-level systems, still the combination of some of them together with their entangling interactions (another key property in the quantum information processing) become in a complex dynamics needing be addressed and modeled under precise control to set programmed quantum processing tasks. Universal quantum gates are simple controlled evolutions resembling some classical computation gates. Despite their simple forms, not always become easy fit the quantum evolution to them. SU(2) decomposition is a mechanism to reduce the dynamics on SU(2) operations in composed quantum processing systems. It lets an easier control of evolution into the structure required by those gates by the adequate election of the basis for the computation grammar. In this arena, SU(2) decomposition has been studied under piecewise magnetic field pulses. Despite, it is completely applicable for time-dependent pulses, which are more affordable technologically, could be continuous and then possibly free of resonant effects. In this work, we combine the SU(2) reduction with linear and quadratic numerical approaches in the solving of time-dependent Schr\"odinger equation to model and to solve the controlled dynamics for two-qubits, the basic block for composite quantum systems being analyzed under the SU(2) reduction. A comparative benchmark of both approaches is presented together with some useful outcomes for the dynamics in the context of quantum information processing operations.

Mesoscopic Continuous and Discrete Channels for Quantum Information Transfer

2006 ◽  
Vol 13 (03) ◽  
pp. 273-280
Author(s):  
Ferdinando de Pasquale ◽  
Gian Luca Giorgi ◽  
Simone Paganelli
Keyword(s):  
Quantum Information ◽  
Finite Number ◽  
Infinite Number ◽  
Anderson Model ◽  
Weak Coupling ◽  
Information Transfer ◽  
Degrees Of Freedom ◽  
Quantum State Transfer ◽  
State Transfer ◽  
Discrete Channels

We study the possibility of realizing perfect quantum state transfer in mesoscopic devices. We discuss the case of the Fano-Anderson model extended to two impurities in a single excitation regime. For a channel with an infinite number of degrees of freedom, we obtain coherent behaviour in the case of strong coupling or in weak coupling off-resonance. For a finite number of degrees of freedom, coherent behaviour is associated to weak coupling and resonance conditions.

SCHEME FOR QUANTUM CLONING AND QUANTUM INFORMATION PROCESSING WITH TRAPPED IONS

2007 ◽  
Vol 21 (12) ◽  
pp. 729-735
Author(s):  
ZHI-MING ZHAN
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Information Processing ◽  
Vibrational Mode ◽  
Trapped Ions ◽  
Distinct Advantage ◽  
Quantum Cloning ◽  
Universal Quantum ◽  
Data Bus

In this paper, a scheme is presented to implement the 1→2 universal quantum cloning machine (UQCM) with trapped ions. In this way, we also show that quantum information can be directly transferred from one ion to another. The distinct advantage of the scheme lies in the fact that it does not use the vibrational mode as the data bus. The vibrational mode is only virtually excited, which makes our scheme insensitive to heating, provided the system remains in the Lamb–Dicke regime.

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