Speeding up transmissions of unknown quantum information along Ising-type quantum channels

2017 ◽  
Vol 26 (1) ◽  
pp. 010303
Author(s):  
W J Guo ◽  
L F Wei
Keyword(s):  
Quantum Information ◽  
Quantum Channels

scholarly journals Construction of genuinely entangled subspacesand the associated bounds on entanglement measures for mixed states

2021 ◽  
Author(s):  
Konstantin Antipin
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Lower Bounds ◽  
Quantum Information Processing ◽  
Multipartite Entanglement ◽  
Quantum Channels ◽  
Valuable Resource ◽  
Mixed States ◽  
Entanglement Measures ◽  
Pure States

Abstract Genuine entanglement is the strongest form of multipartite entanglement. Genuinely entangled pure states contain entanglement in every bipartition and as such can be regarded as a valuable resource in the protocols of quantum information processing. A recent direction of research is the construction of genuinely entangled subspaces — the class of subspaces consisting entirely of genuinely entangled pure states. In this paper we present methods of construction of such subspaces including those of maximal possible dimension. The approach is based on the composition of bipartite entangled subspaces and quantum channels of certain types. The examples include maximal subspaces for systems of three qubits, four qubits, three qutrits. We also provide lower bounds on two entanglement measures for mixed states, the concurrence and the convex-roof extended negativity, which are directly connected with the projection on genuinely entangled subspaces.

scholarly journals INFORMATION TRANSFER RATES IN SPIN QUANTUM CHANNELS

2007 ◽  
Vol 05 (04) ◽  
pp. 439-455 ◽  
Author(s):  
DAVIDE ROSSINI ◽  
VITTORIO GIOVANNETTI ◽  
ROSARIO FAZIO
Keyword(s):  
Quantum Information ◽  
Information Transfer ◽  
Transmission Efficiency ◽  
Spin Chains ◽  
Quantum Channels ◽  
Transfer Rates ◽  
Temporal Correlations ◽  
Spin Quantum ◽  
Communication Efficiency

We analyze the communication efficiency of quantum information transfer along unmodulated spin chains by computing the communication rates of various protocols. The effects of temporal correlations are discussed, showing that they can be exploited to boost the transmission efficiency.

QUANTUM CHANNELS OF THE QUTRIT STATE TELEPORTATION

2011 ◽  
Vol 09 (03) ◽  
pp. 893-901 ◽  
Author(s):  
XIU-LAO TIAN ◽  
GUO-FANG SHI ◽  
Yong ZHAO
Keyword(s):  
Quantum Information ◽  
Quantum System ◽  
Quantum Channel ◽  
Sufficient Condition ◽  
Quantum Channels ◽  
Necessary And Sufficient Condition ◽  
Measurement Matrix ◽  
Parameter Matrix ◽  
Channel Parameter ◽  
Necessary And Sufficient

Qudit quantum system can carry more information than that of qubit, the teleportation of qudit state has significance in quantum information task. We propose a method to teleport a general qutrit state (three-level state) and discuss the necessary and sufficient condition for realizing a successful and perfect teleportation, which is determined by the measurement matrix Tα and the quantum channel parameter matrix (CPM) X. By using this method, we study the channels of two-qutrit state and three-qutrit state teleportation.

A NOTE ON "SPLITTING FOUR ENSEMBLES OF TWO-QUBIT QUANTUM INFORMATION VIA THREE EINSTEIN–PODOLSKY–ROSEN PAIRS"

2010 ◽  
Vol 08 (03) ◽  
pp. 529-533
Author(s):  
YI-MIN LIU ◽  
MING-LING LI ◽  
HUA-MIN GAO ◽  
XIAN-SONG LIU ◽  
ZHAN-JUN ZHANG
Keyword(s):  
Quantum Information ◽  
Recent Literature ◽  
Qubit State ◽  
The Novel ◽  
Quantum Channels ◽  
Einstein Podolsky Rosen

Enlightened by the novel idea in recent literature, we improve the tripartite quantum scheme to be a more economical and efficient one for splitting any two-qubit state in the four specific ensembles with only two Einstein–Podolsky–Rosen pairs as quantum channels.

scholarly journals Graph Approach to Quantum Teleportation Dynamics

2020 ◽  
Vol 2 (3) ◽  
pp. 352-377
Author(s):  
Efrén Honrubia ◽  
Ángel S. Sanz
Keyword(s):  
Quantum Information ◽  
Quantum Teleportation ◽  
Entangled States ◽  
Quantum Channels ◽  
Qubit System ◽  
Alternative Approaches ◽  
Maximally Entangled States ◽  
Usual State ◽  
Vector Description ◽  
Direct Correspondence

Quantum teleportation plays a key role in modern quantum technologies. Thus, it is of much interest to generate alternative approaches or representations that are aimed at allowing us a better understanding of the physics involved in the process from different perspectives. With this purpose, here an approach based on graph theory is introduced and discussed in the context of some applications. Its main goal is to provide a fully symbolic framework for quantum teleportation from a dynamical viewpoint, which makes explicit at each stage of the process how entanglement and information swap among the qubits involved in it. In order to construct this dynamical perspective, it has been necessary to define some auxiliary elements, namely virtual nodes and edges, as well as an additional notation for nodes describing potential states (against nodes accounting for actual states). With these elements, not only the flow of the process can be followed step by step, but they also allow us to establish a direct correspondence between this graph-based approach and the usual state vector description. To show the suitability and versatility of this graph-based approach, several particular teleportation examples are examined in detail, which include bipartite, tripartite, and tetrapartite maximally entangled states as quantum channels. From the analysis of these cases, a general protocol is devised to describe the sharing of quantum information in presence of maximally entangled multi-qubit system.

TRIPARTITION OF ARBITRARY SINGLE-QUBIT QUANTUM INFORMATION BY USING ASYMMETRIC FOUR-QUBIT W STATE

2009 ◽  
Vol 07 (01) ◽  
pp. 349-355 ◽  
Author(s):  
YI-MIN LIU ◽  
XIAO-FENG YIN ◽  
WEN ZHANG ◽  
ZHAN-JUN ZHANG
Keyword(s):  
Quantum Information ◽  
The Other ◽  
W State ◽  
Unitary Operation ◽  
Quantum Channels ◽  
Single Qubit

In this paper we propose a four-party scheme for a sender to achieve the tripartition of his/her arbitrary single-qubit quantum information among three recipients via an asymmetric four-qubit W state as quantum channels. In the scheme, if and only if, the three recipients cooperate together, they can perfectly retrieve the sender's quantum information by performing first two 2-qubit collective unitary operations and then a single-qubit unitary operation. The scheme is symmetric with respect to the reconstruction for any recipient can conclusively recover the quantum information with the other two's helps.

ON THE SECURITY OF DECOHERENCE-FREE SUBSPACES AND SUBSYSTEMS FOR CLASSICAL INFORMATION CONVEYING THROUGH QUANTUM CHANNELS

2013 ◽  
Vol 11 (02) ◽  
pp. 1350022
Author(s):  
ELLOÁ B. GUEDES ◽  
FRANCISCO M. DE ASSIS
Keyword(s):  
Quantum Information ◽  
Communication Systems ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Information Leakage ◽  
Practical Implementation ◽  
Quantum Channels ◽  
Quantum Properties ◽  
Message Exchange ◽  
Decoherence Free Subspaces

Decoherence is one of the main obstacles in quantum information processing. In cryptographic scenarios, in particular, decoherence is not only responsible for the loss of the quantum properties but also for information leakage out to a wiretapper. Given that decoherence must be fought in real-world quantum communication systems, we present a scheme, using decoherence-free subspaces and subsystems, to perform secure classical communications through noisy quantum channels. Using quantum information and wiretap theories, we establish a proof of unconditional security of our scheme. We illustrate our proposal with a non-trivial example and discuss some of its impacts on already existing quantum secure message exchange protocols. Furthermore, we present some up-to-date technologies that can be used for practical implementation of the scheme proposed.

scholarly journals Environmental Effects on Nonlocal Correlations

Quanta ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 57-67
Author(s):  
Tamal Guha ◽  
Bihalan Bhattacharya ◽  
Debarshi Das ◽  
Some Sankar Bhattacharya ◽  
Amit Mukherjee ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Information Processing ◽  
Quantum Information ◽  
Quantum Information Processing ◽  
Classical Mechanics ◽  
Complete Loss ◽  
Quantum Channels ◽  
Output State ◽  
Environmental Interactions ◽  
Nonlocal Correlations

Environmental interactions are ubiquitous in practical instances of any quantum information processing protocol. The interaction results in depletion of various quantum resources and even complete loss in numerous situations. Nonlocality, which is one particular quantum resource marking a significant departure of quantum mechanics from classical mechanics, meets the same fate. In the present work we study the decay in nonlocality to the extent of the output state admitting a local hidden state model. Using some fundamental quantum channels we also demonstrate the complete decay in the resources in the purview of the Bell–Clauser–Horne–Shimony–Holt inequality and a three-settings steering inequality. We also obtain bounds on the parameter of the depolarizing map for which it becomes steerability breaking pertaining to a general class of two qubit states.Quanta 2019; 8: 57–67.

QUANTUM INFORMATION SPLITTING OF TWO-QUBIT STATE WITH MINIMAL CLASSICAL COMMUNICATION AND MEASUREMENT COMPLEXITY

2008 ◽  
Vol 06 (05) ◽  
pp. 1101-1113 ◽  
Author(s):  
GUI-XIA PAN ◽  
YI-MIN LIU ◽  
XUE-QIN ZUO ◽  
WEN ZHANG ◽  
ZHAN-JUN ZHANG
Keyword(s):  
Quantum Information ◽  
Success Probability ◽  
Communication Cost ◽  
Qubit State ◽  
Quantum Information Splitting ◽  
Quantum Channels ◽  
Classical Communication ◽  
Classical Communication Cost ◽  
Special Cases ◽  
Information Splitting

We present a quantum information splitting scheme of a two-qubit state by using two Greenberger–Horne–Zeilinger (GHZ) states as quantum channels. In this scheme, since the sender Alice knows the quantum information in priori, she only needs to perform a two-qubit measurement and publish two classical bits for her two agents Bob and Charlie to reconstruct the quantum information via their mutual assistance. We calculate the success probability and classical communication cost within the scheme. In the general case, Alice can successfully split the state with probability 25% (probabilistic) and the classical communication cost is 4 classical bits. However, in some special cases, the secret states are chosen from a special ensemble, the success probability of our scheme can be increased to 50% or even to 100% (deterministic) after consuming some extra classical bits.

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