scholarly journals Entangling identical bosons in optical tweezers via exchange interaction

2008 ◽  
Vol 86 (4) ◽  
pp. 549-555 ◽  
Author(s):  
N S Babcock ◽  
R Stock ◽  
M G Raizen ◽  
B C Sanders
Keyword(s):  
Quantum Information ◽  
Optical Tweezers ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Weighted Graph ◽  
Selective Excitation ◽  
Composite Particles ◽  
Graph States ◽  
03.65 Ud ◽  
03.67 Mn

We first devise a scheme to perform a universal entangling gate via controlled collisions between pairs of atomic qubits trapped with optical tweezers. Second, we present a modification to this scheme to allow for the preparation of atomic Bell pairs via selective excitation, suitable for quantum-information-processing applications that do not require universality. Both these schemes are enabled by the inherent symmetries of identical composite particles, as originally proposed by Hayes et al. Our scheme provides a technique for producing weighted graph states, entangled resources for quantum communication, and a promising approach to performing a “loophole free” Bell test in a single laboratory.PACS Nos.: 03.65.Ud, 03.67.Mn, 32.80.Pj, 42.50.Vk

On the classical character of control fields in quantum information processing

2002 ◽  
Vol 2 (1) ◽  
pp. 1-13
Author(s):  
S.J. van Enk ◽  
H.J. Kimble
Keyword(s):  
Quantum Computing ◽  
Information Processing ◽  
Quantum Information ◽  
Laser Beam ◽  
Quantum State ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Laser Fields ◽  
Undesirable Property

Control fields in quantum information processing are almost by definition assumed to be classical. In reality, however, when such a field is used to manipulate the quantum state of qubits, the qubits always become slightly entangled with the field. For quantum information processing this is an undesirable property, as it precludes perfect quantum computing and quantum communication. Here we consider the interaction of atomic qubits with laser fields and quantify atom-field entanglement in various cases of interest. We find that the entanglement decreases with the average number of photons \bar{n} in a laser beam as $E\propto\log_2 \bar{n}/\bar{n}$ for $\bar{n}\rightarrow\infty$.

Quantum non-gaussianity from an indefnite causal order of Gaussian operations

2021 ◽  
Author(s):  
Seid Koudia ◽  
Abdelhakim Gharbi
Keyword(s):  
Quantum Information ◽  
Quantum Key Distribution ◽  
Degrees Of Freedom ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Quantum Metrology ◽  
Causal Order ◽  
Gaussian States ◽  
Control Qubit ◽  
Non Gaussian

Quantum non-Gaussian states are considered a useful resource for many tasks in quantum information processing, from quantum metrology and quantum sensing to quantum communication and quantum key distribution. Another useful tool that is gaining attention is the newly constructed quantum switch. Its applications in many tasks in quantum information have been proved to outperform many existing schemes in quantum communication and quantum thermometry. In this contribution, we demonstrate this to be very useful for engineering highly non-Gaussian states from Gaussian operations whose order is controlled by degrees of freedom of a control qubit. The nonconvexity of the set of Gaussian states and the set of Gaussian operations guarantees the emergence of non-Gaussianity after post-selection on the control qubit deterministically, in contrast to existing protocols in the literature. The nonclassicality of the resulting states is discussed accordingly.

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 Harnessing the Exchange Interaction for Quantum Information Processing

2018 ◽  
Author(s):  
Mrittunjoy Guha Majumdar
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Exchange Interaction ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Invariant Subspaces ◽  
Permutation Symmetry ◽  
Physical Systems ◽  
Definition Of ◽  
Swap Operator

In this paper, I propose new models of quantum information processing using the exchange interaction in physical systems. The partial SWAP operator that can be realized using the exchange interaction is used as the underlying resource for defining models of quantum computation, quantum communication, quantum memory and decoherence-free subspaces. Given the non-commutativity of these operators (for adjacent operators operating on a common qubit), a number of quantum states and entanglement patters can be obtained. This zoo of states can be classified, due to the parity constraints and permutation symmetry of the states, into invariant subspaces that are used for the definition of some of the applications in this paper.

scholarly journals PROBLEMS AND PROSPECTS OF CREATION OF QUANTUM COMMUNICATION SYSTEMS

2020 ◽  
pp. 27-33
Author(s):  
I.I. Ryabtsev ◽  
S.P. Yurkevichyus ◽  
A.E. Gritsenko
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Communication Systems ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Scientific Research ◽  
The State ◽  
Processing Technology

Scientific and technological problems and prospects for creating quantum communication systems are herein outlined. A brief analysis of the state of scientific research in this area abroad is carried out. The strengths and weaknesses of the implementation of quantum information processing technology are reflected.

scholarly journals Entanglement of two distant quantum dots with the flip-flop interaction coupled to plasmonic waveguide

2019 ◽  
Vol 33 (21) ◽  
pp. 1950235 ◽  
Author(s):  
Myong-Chol Ko ◽  
Nam-Chol Kim ◽  
Ju-Song Ryom ◽  
Su-Ryon Ri ◽  
Jian-Bo Li
Keyword(s):  
Quantum Dots ◽  
Quantum Information ◽  
Surface Plasmon ◽  
Coupling Strength ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Analytic Solutions ◽  
Flip Flop ◽  
Quantum Device ◽  
Metallic Waveguide

The entanglement of two distant quantum dots coupled to metallic waveguide has been investigated theoretically in the presence of the flip-flop interaction with the analytic solutions of eigenvalue equations of the system. High entanglement of two quantum dots could be achieved by adjusting the direct-coupling strength of two quantum dots, the coupling strength of quantum dots with surface plasmon along metallic waveguide, the group velocity of surface plasmon and detuning. The discussed system with the flip-flop interaction provides us with a rich way to realize the quantum device for quantum information processing, such as quantum communication and quantum computation.

Highlights from the Asia Pacific Region

2014 ◽  
Vol 03 (01) ◽  
pp. 28-38
Author(s):  
APPN Editorial Team
Keyword(s):  
Quantum Information ◽  
Quantum Teleportation ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Logic Gates ◽  
Building Blocks ◽  
Asia Pacific ◽  
Quantum Computers ◽  
Asia Pacific Region ◽  
Quantum Logic Gates

The laws of quantum mechanics enable optical communications with the ultimate capacity and quantum computers to solve certain problems with unprecedented speed. A key ingredient in such quantum information processing is quantum teleportation: the act of transferring quantum information from a sender to a spatially distant receiver by utilizing shared entanglement and classical communications. For example, optical quantum teleportation is essential for various quantum communication protocols. Quantum logic gates based on optical quantum teleportation are one of the building blocks of optical quantum computers.

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