Condition on n-Qubit State For Getting Perfect Quantum Teleportation
Shamiya Javed, Phool Singh Yadav, Ranjana Prakash, Hari Prakash
备注：
The prelim version of this paper has been presented in a national conference, Student Conference on Optics and Photonics (SCOP-2018) held during 4-6 October 2018 at PRL, Ahmadabad
研究表明，采用多量子比特资源的标准量子隐形传态（SQT）的保真度为$(2+C)/3$，其中$C$为传输至接收方的量子比特与其余量子比特之间的两体纠缠资源的并发度。显然，要实现完美SQT，需满足$C=1$。针对一般3量子比特资源，我们推导了以任意基矢表示的态实现完美SQT的条件。Zha等人[Mod. Phys. Lett. B 22, 2523-2528 (2008)]曾研究利用3量子比特资源的完美SQT，但仅给出了以Acin表示的3量子比特标准形式给出的资源态的完美SQT条件。我们提出了一种更易推导的替代表示形式，可得到更具普适性的结果。为说明两种方案的差异，我们构建了一个3量子比特纠缠态实例，该态可实现完美SQT，但未被纳入Zha等人的研究结果中。
英文摘要：
It is shown that standard quantum teleportation (SQT) with multi-qubit resource result in fidelity $(2+C)/3$ where $C$ is concurrence of the resource in bipartite entanglement between qubit going to receiver and rest of the qubits. For perfect SQT, obviously, $C=1$. For a general 3-qubit resource, we find conditions for getting perfect SQT for state expressed in any basis states. Zha et al. [Mod. Phys. Lett. B 22, 2523-2528 (2008)], who studied perfect SQT using 3-qubit resource, reported conditions for perfect SQT for only those resource states which are given in the 3-qubit canonical form of Acin representation. We show that there is an alternative easily derivable representation which gives more generalized results. To illustrate the difference between the two schemes, we build an example of 3-qubit entangled state, giving perfect SQT and not included in Zha et al. results.
Recently, Agrawal and Pati [Phys. Rev. A 74, 062320 (2006)] have given a class of W-states that can be used for perfect teleportation. Here, two canonical forms of perfect quantum channel are presented by transformation operator and the GHZ state and the W state are special case of those two canonical forms of perfect quantum channel. Furthermore, the orthogonal complete measurement bases are given.
We study the possibility of performing perfect teleportation of unknown quantum states from multiple senders to a single receiver with a previously shared stabilizer state. In the model we considered, the utilized stabilizer state is partitioned into several subsystems and then each subsystem is distributed to a distinct party. We present two sufficient conditions for a stabilizer state to achieve a given nonzero teleportation capacity with respect to a given partition plan. The corresponding teleportation protocols are also explicitly given. Interestingly, we find that even mixed stabilizer s…
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Following the previous paper in which quantum teleportation is rig orously discussed with coherent entangled states given by beam splittings, we further discuss two types of models, perfect teleportation model and non-perfect teleportation model, in general scheme. Then the difference among several models, i.e., the perfect models and the non-perfect models, is studied. Our teleportation models are constructed by means of coherent states in some Fock space with counting measures, so that our model can be treated in the frame of usual optical communication.
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Classical and Quantum Resources in Perfect Teleportation
Theoretical Physics Division, Chern Institute of Mathematics, Nankai University（南开大学陈省身数学研究所理论物理部）；Department of Physics, School of Science, Tianjin University（天津大学理学院物理系）
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Quantum teleportation provides a way to transfer unknown quantum states from one system to another via an entangled state as a quantum channel without physical transmission of the object itself. The entangled channel, measurement performed by the sender (Alice), and classical information sent to the receiver (Bob) are three key ingredients in the procedure, which need to cooperate with each other. To study the relationship among the three parts, we propose a scheme for perfect teleportation of a qubit through a high-dimensional quantum channel in a pure state with two equal largest Schmidt coe…
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Impossibility via W states and feasibility via W-like states for perfect quantum teleportation
Graduate School of Science and Engineering, Chiba University（千叶大学理工学研究科）；Department of Physics, Graduate School of Science, Chiba University（千叶大学理学研究科物理系）；Research and Education Center for Natural Sciences, Keio University（庆应义塾大学自然科学与教育研究中心）
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The necessary and sufficient condition for perfect teleportation and superdense coding and all the suitable states for teleportation and superdense coding
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We study teleportation with identical massive particles. Indistinguishability imposes that the relevant degrees of freedom to be teleported are not particles, but rather addressable orthogonal modes. We discuss the performances of teleportation under the constraint of conservation of the total number of particles. The latter inevitably decreases the teleportation fidelity. Moreover, even though a phase reference, given by the coupling to a reservoir, circumverts the constraint, it does not restore perfect deterministic teleportation. The latter is only achievable with some special resource ent…
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The long distance entanglement in finite size open Fermi-Hubbard chains, together with the end-to-end quantum teleportation are investigated. We show the peculiarity of the ground state of the Fermi-Hubbard model to support maximum long distance entanglement, which allows it to operate as a quantum resource for high fidelity long distance quantum teleportation. We determine the physical properties and conditions for creating scalable long distance entanglement and analyze its stability under the effect of the Coulomb interaction and the hopping amplitude. Furthermore, we show that the choice o…
There are a few obstacles, which bring about imperfect quantum teleportation of a continuous variable state, such as unavailability of maximally entangled two-mode squeezed states, inefficient detection and imperfect unitary transformation at the receiving station. We show that all those obstacles can be understood by a combination of an {\it asymmetrically-decohered} quantum channel and perfect apparatuses for other operations. For the asymmetrically-decohered quantum channel, we find some counter-intuitive results; one is that teleportation does not necessarily get better as the channel is i…
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The entanglement dynamics of an anisotropic two-qubit Heisenberg XYZ system in the presence of intrinsic decoherence is studied. The usefulness of such system for performance of the quantum teleportation protocol ${\cal T}_0$ and entanglement teleportation protocol ${\cal T}_1$ is also investigated. The results depend on the initial conditions and the parameters of the system. For the product and maximally entangled initial states, increasing the size of spin-orbit interaction parameter $D$ amplifies the effects of dephasing and hence decreases the asymptotic entanglement and fidelity of telep…
We review and compare Bell-state measurement and quantum teleportation schemes using linear optics with three different types of resources, i.e., two-photon pairs, entangled coherent states and hybrid entangled states. Remarkably, perfect teleportation with linear optics is possible in principle based on a hybrid approach that combines two-photon pairs and entangled coherent states. It turns out that hybrid approach allows to perform Bell-state measurement and local Pauli operations in a deterministic way, while it requires photon number resolving measurements.
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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 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 informati…
Due to the Heisemberg uncertainty principle, it is impossible to design a procedure which permits perfect cloning of an arbitrary, unknown "qubit" (the spin or polarization state of a single quantum system)1,2. However, it is believed that a perfect copying protocol can be achieved, at least in principle, if the qubit to be copied is destroyed in the original system. Quantum teleportation3,4 is supposed to allow for such a result. Here, this belief is shown to be invalidated by a fundamental uncertainty about the number of particles involved in any process, as predicted by Quantum Field Theory…
