scholarly journals Bound entangled states fit for robust experimental verification

Quantum ◽  
2018 ◽  
Vol 2 ◽  
pp. 113 ◽  
Author(s):  
Gael Sentís ◽  
Johannes N. Greiner ◽  
Jiangwei Shang ◽  
Jens Siewert ◽  
Matthias Kleinmann
Keyword(s):  
Density Matrix ◽  
Experimental Verification ◽  
Hypothesis Test ◽  
Statistical Significance ◽  
Tomographic Reconstruction ◽  
Entangled States ◽  
Entangled State ◽  
Full Reconstruction ◽  
Bound Entanglement ◽  
Extra Assumption

Preparing and certifying bound entangled states in the laboratory is an intrinsically hard task, due to both the fact that they typically form narrow regions in state space, and that a certificate requires a tomographic reconstruction of the density matrix. Indeed, the previous experiments that have reported the preparation of a bound entangled state relied on such tomographic reconstruction techniques. However, the reliability of these results crucially depends on the extra assumption of an unbiased reconstruction. We propose an alternative method for certifying the bound entangled character of a quantum state that leads to a rigorous claim within a desired statistical significance, while bypassing a full reconstruction of the state. The method is comprised by a search for bound entangled states that are robust for experimental verification, and a hypothesis test tailored for the detection of bound entanglement that is naturally equipped with a measure of statistical significance. We apply our method to families of states of3×3and4×4systems, and find that the experimental certification of bound entangled states is well within reach.

The Construction and Simulation Analysis of Three-Qubit Hxx Chain Refrigerator Based on Quantum Entangled States

2013 ◽  
Vol 380-384 ◽  
pp. 4849-4855
Author(s):  
Xing Kui Huang
Keyword(s):  
Field Strength ◽  
Simulation Analysis ◽  
Heat Engine ◽  
State Theory ◽  
Entangled States ◽  
Entangled State ◽  
Working Process ◽  
Mapping Analysis ◽  
Quantum Entangled States ◽  
Working Efficiency

Quantum entangled state theory is combined with quantum thermodynamics theory to build quantum entangled state heat engine. The basic nature of three-qubit Hxx chain, and all parameters of the orbit are analyzed. Energy model of quantum entangled state refrigerator in working process is taken as as a theoretical basis to construct three qubits Hxx chain refrigerator based on quantum entangled states. The working nature of the new quantum entangled state refrigerator under different field strength is studied. Compaired with two-qubit Hxxx chain refrigerator based on quantum entangled states and mapping analysis, the working efficiency of three qubits Hxx chain refrigerator based on quantum entangled states is much higher when the field strength is not zero and its working state is more stable.

Infinitely entangled states

2003 ◽  
Vol 3 (4) ◽  
pp. 281-306
Author(s):  
M. Keyl ◽  
D. Schlingemann ◽  
R.F. Werner
Keyword(s):  
Hilbert Spaces ◽  
Degrees Of Freedom ◽  
Entangled States ◽  
Entangled State ◽  
Bounded Operators ◽  
Infinite Dimensional ◽  
Infinite Dimensional Hilbert Space ◽  
Density Operators ◽  
Fundamental Paper ◽  
Extended Notion

For states in infinite dimensional Hilbert spaces entanglement quantities like the entanglement of distillation can become infinite. This leads naturally to the question, whether one system in such an infinitely entangled state can serve as a resource for tasks like the teleportation of arbitrarily many qubits. We show that appropriate states cannot be obtained by density operators in an infinite dimensional Hilbert space. However, using techniques for the description of infinitely many degrees of freedom from field theory and statistical mechanics, such states can nevertheless be constructed rigorously. We explore two related possibilities, namely an extended notion of algebras of observables, and the use of singular states on the algebra of bounded operators. As applications we construct the essentially unique infinite analogue of maximally entangled states, and the singular state used heuristically in the fundamental paper of Einstein, Rosen and Podolsky.

scholarly journals Probabilistic Resumable Quantum Teleportation of a Two-Qubit Entangled State

Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 352 ◽  
Author(s):  
Zhan-Yun Wang ◽  
Yi-Tao Gou ◽  
Jin-Xing Hou ◽  
Li-Ke Cao ◽  
Xiao-Hui Wang
Keyword(s):  
Quantum Channel ◽  
Quantum Teleportation ◽  
The State ◽  
Entangled States ◽  
Entangled State ◽  
Quantum Channels ◽  
Unknown State ◽  
Optimal Probability

We explicitly present a generalized quantum teleportation of a two-qubit entangled state protocol, which uses two pairs of partially entangled particles as quantum channel. We verify that the optimal probability of successful teleportation is determined by the smallest superposition coefficient of these partially entangled particles. However, the two-qubit entangled state to be teleported will be destroyed if teleportation fails. To solve this problem, we show a more sophisticated probabilistic resumable quantum teleportation scheme of a two-qubit entangled state, where the state to be teleported can be recovered by the sender when teleportation fails. Thus the information of the unknown state is retained during the process. Accordingly, we can repeat the teleportion process as many times as one has available quantum channels. Therefore, the quantum channels with weak entanglement can also be used to teleport unknown two-qubit entangled states successfully with a high number of repetitions, and for channels with strong entanglement only a small number of repetitions are required to guarantee successful teleportation.

MULTIPARTY REMOTELY PREPARING MULTIPARTITE EQUATORIAL ENTANGLED STATES IN HIGH DIMENSIONS

2011 ◽  
Vol 09 (06) ◽  
pp. 1437-1448
Author(s):  
YI-BAO LI ◽  
KUI HOU ◽  
SHOU-HUA SHI
Keyword(s):  
Quantum State ◽  
Quantum Channel ◽  
Success Probability ◽  
Quantum States ◽  
Remote State Preparation ◽  
Entangled States ◽  
Entangled State ◽  
High Dimensions ◽  
Original State ◽  
State Preparation

We propose two kinds of schemes for multiparty remote state preparation (MRSP) of the multiparticle d-dimensional equatorial quantum states by using partial entangled state as the quantum channel. Unlike more remote state preparation scheme which only one sender knows the original state to be remotely prepared, the quantum state is shared by two-party or multiparty in this scheme. We show that if and only if all the senders agree to collaborate with each other, the receiver can recover the original state with certain probability. It is found that the total success probability of MRSP is only by means of the smaller coefficients of the quantum channel and the dimension d.

Bidirectional quantum teleportation and cyclic quantum teleportation of multi-qubit entangled states via G-state

2020 ◽  
Vol 34 (28) ◽  
pp. 2050261
Author(s):  
Vikram Verma
Keyword(s):  
Quantum Channel ◽  
Quantum Teleportation ◽  
The Other ◽  
Entangled States ◽  
Entangled State ◽  
Bidirectional Quantum Teleportation

We propose a novel scheme for faithful bidirectional quantum teleportation (BQT) in which Alice can transmit an unknown N-qubit entangled state to Bob and at the same time Bob can transmit an unknown M-qubit entangled state to Alice by using a four-qubit entangled G-state as a quantum channel. We also propose a new scheme for cyclic QT of multi-qubit entangled states by using two G-states as a quantum channel. The advantage of our schemes is that it seems to be much simpler and requires reduced number of qubits in quantum channel as compared with the other proposed schemes.

A novel semi-quantum secret sharing scheme using entangled states

2018 ◽  
Vol 32 (22) ◽  
pp. 1850256 ◽  
Author(s):  
Ai Han Yin ◽  
Yan Tong
Keyword(s):  
Secret Sharing ◽  
Quantum Secret Sharing ◽  
Entangled States ◽  
Entangled State ◽  
Secret Sharing Scheme ◽  
Sharing Scheme ◽  
State Formula ◽  
Quantum Secret Sharing Scheme

Semi-quantum secret sharing (SQSS) can transmit secret messages. Most existing SQSS protocols can only use one or two specific entangled states to share unspecific or specific classical message. In this paper, we propose a novel SQSS protocol using N different unspecific two-particle entangled state [Formula: see text], [Formula: see text] to share unspecific message, in which quantum Alice can transmit classical messages with classical Bob and Charlie. In addition, we have proved that the protocol can strongly resist some forms of eavesdropping.

scholarly journals MAXIMALLY ENTANGLED STATES AND BELL'S INEQUALITY IN RELATIVISTIC REGIME

2009 ◽  
Vol 07 (01) ◽  
pp. 395-401 ◽  
Author(s):  
SHAHPOOR MORADI
Keyword(s):  
Ghz State ◽  
Entangled States ◽  
Entangled State ◽  
Maximally Entangled State ◽  
Expectation Value ◽  
Spin Observables ◽  
Chsh Inequality ◽  
Relativistic Regime ◽  
Maximal Violation ◽  
Maximally Entangled States

In this letter we show that in the relativistic regime, maximally entangled state of two spin-1/2 particles not only gives maximal violation of the Bell-CHSH inequality but also gives the largest violation attainable for any pairs of four spin observables that are noncommuting for both systems. Also, we extend our results to three spin-1/2 particles. We obtain the largest eigenvalue of Bell operator and show that this value is equal to the expectation value of Bell operator on GHZ state.

scholarly journals Clocks without “Time” in Entangled-State Experiments

Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 434
Author(s):  
F. Hadi Madjid ◽  
John M. Myers
Keyword(s):  
General Relativity ◽  
Special Relativity ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Entangled States ◽  
Entangled State ◽  
Definition Of ◽  
Do So

Entangled states of light exhibit measurable correlations between light detections at separated locations. These correlations are exploited in entangled-state quantum key distribution. To do so involves setting up and maintaining a rhythm of communication among clocks at separated locations. Here, we try to disentangle our thinking about clocks as used in actual experiments from theories of time, such as special relativity or general relativity, which already differ between each other. Special relativity intertwines the concept of time with a particular definition of the synchronization of clocks, which precludes synchronizing every clock to every other clock. General relativity imposes additional barriers to synchronization, barriers that invite seeking an alternative depending on any global concept of time. To this end, we focus on how clocks are actually used in some experimental situations. We show how working with clocks without worrying about time makes it possible to generalize some designs for quantum key distribution and also clarifies the need for alternatives to the special-relativistic definition of synchronization.

Experimental verification of full reconstruction of the near-field with a metamaterial lens

2010 ◽  
Vol 97 (14) ◽  
pp. 144102 ◽  
Author(s):  
Tiago A. Morgado ◽  
João S. Marcos ◽  
Mário G. Silveirinha ◽  
Stanislav I. Maslovski
Keyword(s):  
Experimental Verification ◽  
Near Field ◽  
Full Reconstruction

Generalized three-party sharing of operations on remote single qutrit

2014 ◽  
Vol 12 (03) ◽  
pp. 1450011 ◽  
Author(s):  
Pengfei Xing ◽  
Yimin Liu ◽  
Chuanmei Xie ◽  
Xiansong Liu ◽  
Zhanjun Zhang
Keyword(s):  
Success Probability ◽  
Entangled States ◽  
Entangled State ◽  
Quantum Channels ◽  
Channel State ◽  
Classical Communication ◽  
Maximally Entangled State ◽  
Quantum Operations ◽  
Local Operation ◽  
Maximally Entangled States

Two three-party schemes are put forward for sharing quantum operations on a remote qutrit with local operation and classical communication as well as shared entanglements. The first scheme uses a two-qutrit and three-qutrit non-maximally entangled states as quantum channels, while the second replaces the three-qutrit non-maximally entangled state with a two-qutrit. Both schemes are treated and compared from the four aspects of quantum and classical resource consumption, necessary-operation complexity, success probability and efficiency. It is found that the latter is overall more optimal than the former as far as a restricted set of operations is concerned. In addition, comparisons of both schemes with other four relevant ones are also made to show their two features, including degree generalization and channel-state generalization. Furthermore, some concrete discussions on both schemes are made to expose their important features of security, symmetry and experimental feasibility. Particularly, it is revealed that the success probabilities and intrinsic efficiencies in both schemes are completely determined by the shared entanglement.

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