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- 摘要
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[Texts and Readings in Physical Sciences] Open Quantum Systems Volume 20 (Dynamics of Nonclassical Evolution) || Open Quantum System at Interface with Quantum Information
摘要： This chapter is devoted to the interface between open system ideas and the burgeoning field of quantum information. Quantum information is, as the name suggests, the broad name given to information tasks that make use of the laws of quantum mechanics. It encompasses within its purview, communication, computation and foundational information theoretical tasks. Information theoretic ideas pervade the whole of physics and make inroads beyond it. As it involves encoding, transmission and decoding of information as bits or qubits, all of which are very sensitive to their ambient environment, they provide a fruitful ground for the application of open system ideas. In fact, this chapter and the next one bear testimony to this.
关键词： quantum information,open quantum systems,quantum computation,quantum error correction,quantum communication
更新于2025-09-23 15:21:01
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Versatile relative entropy bounds for quantum networks
摘要： We provide a versatile upper bound on the number of maximally entangled qubits, or private bits, shared by two parties via a generic adaptive communication protocol over a quantum network when the use of classical communication is not restricted. Although our result follows the idea of Azuma et al (2016 Nat. Commun. 7 13523) of splitting the network into two parts, our approach relaxes their strong restriction, consisting of the use of a single entanglement measure in the quanti?cation of the maximum amount of entanglement generated by the channels. In particular, in our bound the measure can be chosen on a channel-by-channel basis, in order to make it as tight as possible. This enables us to apply the relative entropy of entanglement, which often gives a state-of-the-art upper bound, on every Choi-simulable channel in the network, even when the other channels do not satisfy this property. We also develop tools to compute, or bound, the max-relative entropy of entanglement for channels that are invariant under phase rotations. In particular, we present an analytical formula for the max-relative entropy of entanglement of the qubit amplitude damping channel.
关键词： quantum networks,quantum communication,quantum information
更新于2025-09-23 15:21:01
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Near optimal discrimination of binary coherent signals via atom–light interaction
摘要： We study the discrimination of weak coherent states of light with significant overlaps by nondestructive measurements on the light states through measuring atomic states that are entangled to the coherent states via dipole coupling. In this way, the problem of measuring and discriminating coherent light states is shifted to finding the appropriate atom–light interaction and atomic measurements. We show that this scheme allows us to attain a probability of error extremely close to the Helstrom bound, the ultimate quantum limit for discriminating binary quantum states, through the simple Jaynes–Cummings interaction between the field and ancilla with optimized light–atom coupling and projective measurements on the atomic states. Moreover, since the measurement is nondestructive on the light state, information that is not detected by one measurement can be extracted from the post-measurement light states through subsequent measurements.
关键词： Helstrom bound,state discrimination,atom–light interaction,nondestructive measurement,quantum communication,coherent state
更新于2025-09-23 15:21:01
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Controller-independent quantum bidirectional communication using non-maximally entangled states
摘要： In the recent past, Mohapatra and Balakrishnan (Quantum Inf Process 16:147, 2017) proposed a controller-independent bidirectional quantum direct communication protocol using Bell states. In this work, we show the possibility of the achieving same protocol with non-maximally entangled states without compromising on the security and the ef?ciency of the protocol. We exploit the degree of entanglement as an additional security parameter. By doing so, the eavesdropper always gets detected in the initial stages of the protocol in the case of an intercept and resend attack. On the other hand, there is only 25% chance that the eavesdropper goes undetected in the initial stages of the protocol proposed by Mohapatra and Balakrishnan. Thus, the proposed protocol can be implemented with the viable physical resources.
关键词： Non-maximally entangled states,Quantum communication,Bidirectional communication,Quantum cryptography
更新于2025-09-23 15:19:57
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All-photonic quantum teleportation using on-demand solid-state quantum emitters
摘要： All-optical quantum teleportation lies at the heart of quantum communication science and technology. This quantum phenomenon is built up around the nonlocal properties of entangled states of light that, in the perspective of real-life applications, should be encoded on photon pairs generated on demand. Despite recent advances, however, the exploitation of deterministic quantum light sources in push-button quantum teleportation schemes remains a major open challenge. Here, we perform an important step toward this goal and show that photon pairs generated on demand by a GaAs quantum dot can be used to implement a teleportation protocol whose fidelity violates the classical limit (by more than 5 SDs) for arbitrary input states. Moreover, we develop a theoretical framework that matches the experimental observations and that defines the degree of entanglement and indistinguishability needed to overcome the classical limit independently of the input state. Our results emphasize that on-demand solid-state quantum emitters are one of the most promising candidates to realize deterministic quantum teleportation in practical quantum networks.
关键词： GaAs quantum dot,entangled photon pairs,quantum emitters,quantum teleportation,quantum communication
更新于2025-09-23 15:19:57
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[IEEE 2019 16th China International Forum on Solid State Lighting & 2019 International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS) - Shenzhen, China (2019.11.25-2019.11.27)] 2019 16th China International Forum on Solid State Lighting & 2019 International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS) - A Comparative Study of the Lifetimes of High-End and Low-Cost Off-Line LED Drivers Under Accelerated Test Conditions
摘要： In this paper, we present the following quantum compression protocol ‘P ’: Let ρ, σ be quantum states, such that S (ρ(cid:2)σ ) def= Tr(ρ log ρ ? ρ log σ ), the relative entropy between ρ and σ , is finite. Alice gets to know the eigendecomposition of ρ. Bob gets to know the eigendecomposition of σ . Both Alice and Bob know S (ρ(cid:2)σ ) and an error parameter ε. Alice and Bob use shared entanglement and after communication of O((S(ρ(cid:2)σ ) + 1)/ε4) bits from Alice to Bob, Bob ends up with a quantum state ?ρ, such that F(ρ, ?ρ) ≥ 1 ? 5ε, where F(·) represents fidelity. This result can be considered as a non-commutative generalization of a result due to Braverman and Rao where they considered the special case when ρ and σ are classical probability distributions (or commute with each other) and use shared randomness instead of shared entanglement. We use P to obtain an alternate proof of a direct-sum result for entanglement assisted quantum one-way communication complexity for all relations, which was first shown by Jain et al.. We also present a variant of protocol P in which Bob has some side information about the state with Alice. We show that in such a case, the amount of communication can be further reduced, based on the side information that Bob has. Our second result provides a quantum analog of the widely used classical correlated-sampling protocol. For example, Holenstein used the classical correlated-sampling protocol in his proof of a parallel-repetition theorem for two-player one-round games.
关键词： quantum communication complexity,compression protocols,correlated sampling,Quantum information theory,direct sum results
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Development and Investigation of Precision Laser-Interferometric Meter for Distance and Displacement Monitoring
摘要： We report the design and implementation of a complete electronics platform for conducting a quantum optics experiment that will be operated on board a 1U CubeSat (a 10 × 10 × 10 cm satellite). The quantum optics experiment is designed to produce polarization-entangled photon pairs using nonlinear optical crystals and requires opto-electronic components such as a pump laser, single photon detectors, and liquid crystal-based polarization rotators in addition to passive optical elements. The platform provides mechanical support for the optical assembly. It also communicates autonomously with the host satellite to provide experiment data for transmission to a ground station. A limited number of commands can be transmitted from ground to the platform enabling it to switch experimental modes. This platform requires less than 1.5 W for all operations, and is space qualified. The implementation of this electronics platform is a major step on the road to operating quantum communication experiments using nanosatellites.
关键词： space-based quantum communication,nanosatellite,photon entanglement,CubeSat
更新于2025-09-23 15:19:57
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Ultra-Wideband Optically Controlled Frequency Selective Surface
摘要： We report the design and implementation of a complete electronics platform for conducting a quantum optics experiment that will be operated on board a 1U CubeSat (a 10 × 10 × 10 cm satellite). The quantum optics experiment is designed to produce polarization-entangled photon pairs using nonlinear optical crystals and requires opto-electronic components such as a pump laser, single photon detectors, and liquid crystal-based polarization rotators in addition to passive optical elements. The platform provides mechanical support for the optical assembly. It also communicates autonomously with the host satellite to provide experiment data for transmission to a ground station. A limited number of commands can be transmitted from ground to the platform enabling it to switch experimental modes. This platform requires less than 1.5 W for all operations, and is space qualified. The implementation of this electronics platform is a major step on the road to operating quantum communication experiments using nanosatellites.
关键词： space-based quantum communication,nanosatellite,photon entanglement,CubeSat
更新于2025-09-23 15:19:57
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Entanglement Swapping with Photons Generated on Demand by a Quantum Dot
摘要： Photonic entanglement swapping, the procedure of entangling photons without any direct interaction, is a fundamental test of quantum mechanics and an essential resource to the realization of quantum networks. Probabilistic sources of nonclassical light were used for seminal demonstration of entanglement swapping, but applications in quantum technologies demand push-button operation requiring single quantum emitters. This, however, turned out to be an extraordinary challenge due to the stringent prerequisites on the efficiency and purity of the generation of entangled states. Here we show a proof-of-concept demonstration of all-photonic entanglement swapping with pairs of polarization-entangled photons generated on demand by a GaAs quantum dot without spectral and temporal filtering. Moreover, we develop a theoretical model that quantitatively reproduces the experimental data and provides insights on the critical figures of merit for the performance of the swapping operation. Our theoretical analysis also indicates how to improve state-of-the-art entangled-photon sources to meet the requirements needed for implementation of quantum dots in long-distance quantum communication protocols.
关键词： quantum communication,quantum dot,entanglement swapping,quantum networks
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Improvement of Passivation Quality by Post-Crystallization Treatments with Different Methods for High Quality Tunnel Oxide Passivated Contact c-Si Solar Cells
摘要： We present practical GHz-clocked QKD systems, next generation entanglement QKD technologies, and QKD platform to manage the secure keys and to support a variety of applications. We then show the intrinsic limit of QKD, i.e., a key rate bound, and discuss how to realize the provable (information theoretic) security with a larger secrecy capacity over longer distances. In particular, we present a basic theory of physical layer cryptography, which characterizes the secrecy capacity, and engineers the tradeoff between the efficiency of reliable transmission and secrecy of communication. We introduce a concept to unify these schemes in photonic network, referred to as quantum photonic network. Future issues for realizing this new network paradigm are discussed.
关键词： Quantum communication,photonic network,quantum key distribution,quantum cryptography
更新于2025-09-19 17:13:59