Entangled coherent states versus entangled photon pairs for quantum information processing under photon loss effects

2011 ◽  
Author(s):  
Kimin Park ◽  
Hyunseok Jeong ◽  
Timothy Ralph ◽  
Ping Koy Lam
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Coherent States ◽  
Quantum Information Processing ◽  
Photon Pairs ◽  
Entangled Photon Pairs ◽  
Photon Loss ◽  
Entangled Coherent States

Ququats as superposition of coherent states and their application in quantum information processing

2021 ◽  
pp. 2150013
Author(s):  
Manoj K. Mishra ◽  
Hari Prakash ◽  
Vibhuti B. Jha
Keyword(s):  
Hilbert Space ◽  
Information Processing ◽  
Quantum Information ◽  
Quantum Channel ◽  
Coherent States ◽  
Beam Splitter ◽  
Quantum Information Processing ◽  
Key Distribution ◽  
Dimensional Hilbert Space ◽  
Entangled Coherent States

Superposition of optical coherent states (SCS) [Formula: see text], possessing opposite phases, plays an important role as qubits in quantum information processing tasks like quantum computation, teleportation, key distribution, etc. and are of fundamental importance in testing quantum mechanics. Passage of such SCS from a 50:50 beam splitter leads to generation of entangled coherent states. Recently, ququats and qutrits defined in four- and three-dimensional Hilbert space, respectively, have attracted much attention as they offer advantage in secure quantum communication. However, practical utilization of these advantages essentially requires physical realization of quantum optical ququats and qutrits. Here, we define four new multi-photonic states (MPS) with [Formula: see text] (here, [Formula: see text] or 3 and [Formula: see text]) numbers of photon and show how the SCS can be used to encode ququat using these MPS as basis vectors of a four-dimensional Hilbert space. When these MPS fall upon a 50:50 beam splitter, the resulting states are bipartite four-component entangled coherent states (BFECS) equivalently representing the entangled ququats. We briefly discuss the photon statistical properties of such MPS and BFECS. We show that these MPS and BFECS can be synthesized using even coherent states as input to an interferometer. We give a simple linear optical protocol for almost perfect teleportation of a ququat encoded in SCS with the aid of BFECS as quantum channel. We also describe how these ququats can be used for realization of higher-dimensional BB84 protocol to increase the security of quantum key distribution. Finally, we discuss the possible advantages of using SCS as ququats and BFECS as quantum channel in different quantum information processing tasks.

Entangled coherent states for quantum information processing

Optik ◽  
2014 ◽  
Vol 125 (15) ◽  
pp. 3788-3790 ◽  
Author(s):  
Syed Hamad Bukhari ◽  
Samia Aslam ◽  
Faiza Mustafa ◽  
Ayesha Jamil ◽  
Salman Naeem Khan ◽  
...  
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Coherent States ◽  
Quantum Information Processing ◽  
Entangled Coherent States

scholarly journals Heralded orthogonalisation of coherent states and their conversion to discrete-variable superpositions

2017 ◽  
Vol 4 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Regina Kruse ◽  
Christine Silberhorn ◽  
Tim Bartley
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Coherent States ◽  
Quantum Information Processing ◽  
Fundamental Property ◽  
Discrete Variable ◽  
Successful Operation ◽  
State Discrimination ◽  
Unambiguous State Discrimination

Abstract The nonorthogonality of coherent states is a fundamental property which prevents them from being perfectly and deterministically discriminated. Here, we present an experimentally feasible protocol for the probabilistic orthogonalisation of a pair of coherent states, independent of their amplitude and phase. In contrast to unambiguous state discrimination, a successful operation of our protocol is heralded without measuring the states. As such, they remain suitable for further manipulation and the obtained orthogonal states serve as a discretevariable basis. Therefore, our protocol doubles as a simple continuous-to-discrete variable converter, which may find application in hybrid continuous-discrete quantum information processing protocols.

scholarly journals A versatile waveguide source of photon pairs for chip-scale quantum information processing

2009 ◽  
Vol 17 (8) ◽  
pp. 6727 ◽  
Author(s):  
Jun Chen ◽  
Aaron J. Pearlman ◽  
Alexander Ling ◽  
Jingyun Fan ◽  
Alan L. Migdall
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Information Processing ◽  
Photon Pairs

scholarly journals Coherent preorder of quantum states

2020 ◽  
Vol 20 (13&14) ◽  
pp. 1124-1137
Author(s):  
Zhaofang Bai ◽  
Shuanping Shuanping Du
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Coherent States ◽  
Quantum Coherence ◽  
Quantum Information Processing ◽  
Quantum States ◽  
Mixed States ◽  
Quantum Hypothesis ◽  
Quantum Hypothesis Testing

As an important quantum resource, quantum coherence play key role in quantum information processing. It is often concerned with manipulation of families of quantum states rather than individual states in isolation. Given two pairs of coherent states $(\rho_1,\rho_2)$ and $(\sigma_1,\sigma_2)$, we are aimed to study how can we determine if there exists a strictly incoherent operation $\Phi$ such that $\Phi(\rho_i) =\sigma_i,i = 1,2$. This is also a classic question in quantum hypothesis testing. In this note, structural characterization of coherent preorder under strongly incoherent operations is provided. Basing on the characterization, we propose an approach to realize coherence distillation from rank-two mixed coherent states to $q$-level maximally coherent states. In addition, one scheme of coherence manipulation between rank-two mixed states is also presented.

scholarly journals Almost minimum error discrimination of N-ary weak coherent states by Jaynes-Cummings Hamiltonian dynamics

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Min Namkung ◽  
Younghun Kwon
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum State ◽  
Coherent States ◽  
Quantum Information Processing ◽  
Hamiltonian Dynamics ◽  
Quantum State Discrimination ◽  
Minimum Error ◽  
State Discrimination

AbstractQuantum state discrimination of coherent states has been one of important problems in quantum information processing. Recently, R. Han et al. showed that minimum error discrimination of two coherent states can be nearly done by using Jaynes-Cummings Hamiltonian. In this paper, based on the result of R. Han et al., we propose the methods where minimum error discrimination of more than two weak coherent states can be nearly performed. Specially, we construct models which can do almost minimum error discrimination of three and four coherent states. Our result can be applied to quantum information processing of various coherent states.

scholarly journals Photon engineering for quantum information processing

2003 ◽  
Vol 3 (special) ◽  
pp. 480-502
Author(s):  
A.B. U'Ren ◽  
K. Banaszek ◽  
I.A. Walmsley
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Interference ◽  
Quantum Information Processing ◽  
Logic Gate ◽  
Optical Systems ◽  
Two Photon ◽  
Entangled Photon Pairs ◽  
Available Technology ◽  
Photon States

We study distinguishing information in the context of quantum interference involving more than one parametric downconversion (PDC) source and in the context of generating polarization-entangled photon pairs based on PDC. We arrive at specific design criteria for two-photon sources so that when used as part of complex optical systems, such as photon-based quantum information processing schemes, distinguishing information between the photons is eliminated guaranteeing high visibility interference. We propose practical techniques which lead to suitably engineered two-photon states that can be realistically implemented with available technology. Finally, we study an implementation of the nonlinear-sign shift (NS) logic gate with PDC sources and show the effect of distinguishing information on the performance of the gate.

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