IMPLEMENTATION OF NON-LOCAL CNOT WITH MULTIPLE TARGETS OPERATION BY GHZ STATE AND ENTANGLED PURIFICATION

2004 ◽  
Vol 18 (20n21) ◽  
pp. 2953-2961 ◽  
Author(s):  
LIBING CHEN ◽  
HONG LU ◽  
WEICHENG CHEN
Keyword(s):  
Quantum Channel ◽  
Ghz State ◽  
Successful Implementation ◽  
Multiple Targets ◽  
Ghz States ◽  
Physical Resources ◽  
Local Quantum ◽  
Non Local ◽  
Purification Protocol ◽  
Unit Probability

We show how a non-local quantum CNOT with (N-1)-target operation can be implemented with unit fidelity and unit probability by using a N-qubit maximally entangled GHZ state as quantum channel. We also put forward two schemes for probabilistic implementing the operation with unit fidelity by employing a partially entangled pure GHZ state as quantum channel. The overall physical resources required for accomplishing these schemes are different, and the successful implementation probabilities are also different. We also point out the non-local CNOT with (N-1)-target operation can be used as a purification protocol to concentrate entanglement from an ensemble of partially entangled GHZ states into a subensemble of maximally entangled ones.

REMOTE INTERACTIONS ON DISTRIBUTED QUANTUM SYSTEMS: NON-LOCAL CONDITIONAL OPERATIONS AND PRODUCTION OF MULTIPARTICLE ENTANGLED STATE

2005 ◽  
Vol 19 (20) ◽  
pp. 3261-3271 ◽  
Author(s):  
LIBING CHEN ◽  
HONG LU ◽  
WEICHENG CHEN
Keyword(s):  
Quantum Channel ◽  
Quantum Computer ◽  
Entangled State ◽  
Multiple Targets ◽  
Simple Method ◽  
Single Target ◽  
Local Quantum ◽  
Spatially Distributed ◽  
Non Local ◽  
Unit Probability

We present a systematic simple method for constructing non-local quantum conditional rotation with single target and multiple targets operations. We firstly show how a non-local conditional rotation with single target operation can be implemented with unit fidelity and unit probability by using a maximally entangled pair as quantum channel. We also put forward a scheme for probabilistically implementing the operation with unit fidelity by employing a partially entangled pair as quantum channel. The required physical resources for implementation of the non-local operation in these two cases are discussed. We further consider non-local conditional rotation with multiple targets operations on N spatially distributed systems, and show that the number of possible distinct operations increases here exponentially, with the available number of entangled pairs that are initially distributed between systems. We also point out that the non-local conditional rotation operation can be used to generate multiparticle entanglement between particles belonging to distant users in a communication network and distributed quantum computer.

CONTROLLED AND REMOTE IMPLEMENTATION OF A SPLIT QUANTUM ROTATION AND SENDER-ENCODED SECRET SHARING

2010 ◽  
Vol 24 (04n05) ◽  
pp. 431-437 ◽  
Author(s):  
LIBING CHEN ◽  
YUHUA LIU ◽  
HONG LU
Keyword(s):  
Secret Sharing ◽  
Quantum Secret Sharing ◽  
Ghz State ◽  
Quantum Network ◽  
Entanglement Property ◽  
Theoretical Scheme ◽  
Einstein Podolsky Rosen ◽  
Unit Probability

A quantum rotation can be divided into M pieces and teleported from a sender onto M distant receivers via the control of N agents in a quantum network. We utilize the entanglement property of a (2M + N + 1)-qubit Einstein–Podolsky–Rosen (EPR) — Greenberger–Horne–Zeilinger (GHZ) state to design a theoretical scheme for implementing these rotations remotely with unit fidelity and unit probability. The feature of the scheme is that, apart from a sender and M receivers, N agents are included in the process as controllers. Should any one of the N agents not cooperate, the receivers could not gain the original rotations. This scheme can be used to sender-encoded quantum secret sharing. It definitely has the strong security.

Teleportation and dense coding via a multiparticle quantum channel of the GHZ-class

2002 ◽  
Vol 2 (5) ◽  
pp. 367-378
Author(s):  
V.N. Gorbachev ◽  
A.I. Zhiliba ◽  
A.I. Trubilko ◽  
A.A. Rodichkina
Keyword(s):  
Quantum Channel ◽  
Entangled States ◽  
Dense Coding ◽  
Ghz States ◽  
Classical Capacity ◽  
Coding Schemes ◽  
One To One

A set of protocols for teleportation and dense coding schemes based on a multiparticle quantum channel, represented by the $N$-particle entangled states of the GHZ class, is introduced. Using a found representation for the GHZ states, it was shown that for dense coding schemes enhancement of the classical capacity of the channel due from entanglement is $N/N-1$. Within the context of our schemes it becomes clear that there is no one-to one correspondence between teleportation and dense coding schemes in comparison when the EPR channel is exploited. A set of schemes, for which two additional operations as entanglement and disentanglement are permitted, is considered.

scholarly journals Local and Non-Local Invasive Measurements on Two Quantum Spins Coupled via Nanomechanical Oscillations

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1078
Author(s):  
Dimitrios Maroulakos ◽  
Levan Chotorlishvili ◽  
Dominik Schulz ◽  
Jamal Berakdar
Keyword(s):  
Quantum Coherence ◽  
Indirect Measurement ◽  
Quantum Spin ◽  
Quantum States ◽  
Spin Interaction ◽  
First Case ◽  
Composite Quantum System ◽  
Local Quantum ◽  
Non Local ◽  
Quantum Spins

Symmetry plays the central role in the structure of quantum states of bipartite (or many-body) fermionic systems. Typically, symmetry leads to the phenomenon of quantum coherence and correlations (entanglement) inherent to quantum systems only. In the present work, we study the role of symmetry (i.e., quantum correlations) in invasive quantum measurements. We consider the influence of a direct or indirect measurement process on a composite quantum system. We derive explicit analytical expressions for the case of two quantum spins positioned on both sides of the quantum cantilever. The spins are coupled indirectly to each others via their interaction with a magnetic tip deposited on the cantilever. Two types of quantum witnesses can be considered, which quantify the invasiveness of a measurement on the systems’ quantum states: (i) A local quantum witness stands for the consequence on the quantum spin states of a measurement done on the cantilever, meaning we first perform a measurement on the cantilever, and subsequently a measurement on a spin. (ii) The non-local quantum witness signifies the response of one spin if a measurement is done on the other spin. In both cases the disturbance must involve the cantilever. However, in the first case, the spin-cantilever interaction is linear in the coupling constant Ω , where as in the second case, the spin-spin interaction is quadratic in Ω . For both cases, we find and discuss analytical results for the witness.

Quantum dialogue protocol with four-mode continuous variable GHZ state

2019 ◽  
Vol 33 (05) ◽  
pp. 1950033 ◽  
Author(s):  
Ming-Hui Zhang ◽  
Jin-Ye Peng ◽  
Zheng-Wen Cao
Keyword(s):  
Channel Capacity ◽  
Quantum Channel ◽  
Beam Splitter ◽  
Information Leakage ◽  
Continuous Variable ◽  
Ghz State ◽  
Quantum States ◽  
Quantum Dialogue ◽  
Discrete Variable ◽  
Secret Information

Quantum dialogue can realize the mutual transmission of secret information between two legal users. In most of the existing quantum dialogue protocols, the information carriers applied in quantum dialogue are discrete variable (DV) quantum states. However, there are certain limitations on the preparation and detection of DV quantum states with current techniques. Continuous variable (CV) quantum states can overcome these problems effectively while improving the quantum channel capacity. In this paper, we propose a quantum dialogue protocol with four-mode continuous variable GHZ state. Compared with the existing CV-based quantum dialogue protocols, the protocol allows two users to transmit two groups of secret information with different lengths to each other simultaneously. The channel capacity of the protocol has been improved as each traveling mode carries two- or four-bits of information. In addition, the protocol has been proved to be secure against information leakage problem and some common attacks, such as beam splitter attack and intercept-and-resend attack.

scholarly journals Renormalization and conformal invariance of non-local quantum electrodynamics

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Matthew Heydeman ◽  
Christian B. Jepsen ◽  
Ziming Ji ◽  
Amos Yarom
Keyword(s):  
Conformal Invariance ◽  
Quantum Electrodynamics ◽  
Local Quantum ◽  
Non Local

QUANTUM TELEPORTATION OF AN ARBITRARY N-QUBIT STATE VIA NON-MAXIMALLY ENTANGLED STATE

2007 ◽  
Vol 05 (05) ◽  
pp. 673-683 ◽  
Author(s):  
YU-LING LIU ◽  
ZHONG-XIAO MAN ◽  
YUN-JIE XIA
Keyword(s):  
Quantum Teleportation ◽  
Success Probability ◽  
Qubit State ◽  
Bell States ◽  
Entangled State ◽  
Quantum Channels ◽  
Maximally Entangled State ◽  
Ghz States ◽  
Measurement Basis ◽  
Unit Probability

We explicitly present two schemes for quantum teleportation of an arbitrary N-qubit entangled state using, respectively, non-maximally entangled Bell states and GHZ states as the quantum channels, and generalized Bell states as the measurement basis. The scheme succeeds with unit fidelity but less than unit probability. By introducing additional qubit and unitary operations, the success probability of these two schemes can be increased.

scholarly journals Controlled and Secure Direct Communication Using GHZ State and Teleportation

2004 ◽  
Vol 59 (9) ◽  
pp. 597-601 ◽  
Author(s):  
T. Gao
Keyword(s):  
Quantum Channel ◽  
Quantum Teleportation ◽  
Ghz State ◽  
Secret Message ◽  
Controlled Quantum Teleportation ◽  
Direct Communication ◽  
The Public ◽  
Theoretical Scheme ◽  
Secret Communication ◽  
Two Sides

A theoretical scheme for controlled and secure direct communication is proposed. The communication is based on GHZ state and controlled quantum teleportation. After insuring the security of the quantum channel (a set of qubits in the GHZ state), Alice encodes the secret message directly on a sequence of particle states in the GHZ state and transmits them to Bob, supervised by Charlie using controlled quantum teleportation. Bob can read out the encoded messages directly by the measurement on his qubits. In this scheme, the controlled quantum teleportation transmits Alice’s message without revealing any information to a potential eavesdropper. Because there is not a transmission of the qubit carrying the secret messages between Alice and Bob in the public channel, it is completely secure for controlled and direct secret communication if a perfect quantum channel is used. The feature of this scheme is that the communication between two sides depends on the agreement of a third side.

Sign in / Sign up

Export Citation Format

Share Document