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We propose a model of a programmable quantum processing device realizable with existing nanophotonic technologies and which can be viewed as a basis for new high performance hardware architectures. We present protocols and their physical…

The Quantum Key Distribution protocol can encode a single quantum state and implements an information-theoretically secure key distribution protocol in communication. In the actual QKD experimental system, there are usually two encoding…

Quantum Physics · Physics 2020-08-26 Gao Feifei , Li Zhihui , Liu Chengji , Han Duo

The study of quantum cryptography and quantum entanglement has traditionally been based on two-level quantum systems (qubits) and more recently on three-level systems (qutrits). We investigate several classes of state-dependent quantum…

Quantum Physics · Physics 2007-05-23 Thomas Durt , Bob Nagler

Single photons provide excellent quantum information carriers, but current schemes for preparing, processing and measuring them are inefficient. For example, down-conversion provides heralded, but randomly timed single photons, while…

Quantum Physics · Physics 2012-02-07 N. K. Langford , S. Ramelow , R. Prevedel , W. J. Munro , G. J. Milburn , A. Zeilinger

We describe and discuss a solid state proposal for quantum computation with mobile spin qubits in one-dimensional systems, based on recent advances in spintronics. Static electric fields are used to implement a universal set of quantum…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. E. Popescu , R. Ionicioiu

A quantum bit encoding converter between qubits of different forms is experimentally demonstrated, paving the way to efficient networks for optical quantum computing and communication.

Quantum Physics · Physics 2023-02-14 Hyunseok Jeong

We present a unified universal quantum cloning machine, which combines several different existing universal cloning machines together including the asymmetric case. In this unified framework, the identical pure states are projected equally…

Quantum Physics · Physics 2013-05-29 Yi-Nan Wang , Han-Duo Shi , Zhao-Xi Xiong , Li Jing , Xi-Jun Ren , Liang-Zhu Mu , Heng Fan

It is known that in phase covariant quantum cloning the equatorial states on the Bloch sphere can be cloned with a fidelity higher than the optimal bound established for universal quantum cloning. We generalize this concept to include other…

Quantum Physics · Physics 2009-11-07 V. Karimipour , A. T. Rezakhani

Continuous phase modulation (CPM) with 1-bit quantization at the receiver is promising in terms of energy and spectral efficiency. In this study, CPM waveforms with symbol durations significantly shorter than the inverse of the signal…

Information Theory · Computer Science 2019-10-16 Rodrigo R. M. de Alencar , Lukas T. N. Landau

In Ref. [Phys. Rev. A 100, 062317 (2019)], the authors reported an algorithm to implement, in a circuit-based quantum computer, a general quantum measurement (GQM) of a two-level quantum system, a qubit. Even though their algorithm seems…

Quantum Physics · Physics 2023-02-10 Douglas F. Pinto , Marcelo S. Zanetti , Marcos L. W. Basso , Jonas Maziero

An unknown quantum state cannot be copied on demand and broadcast freely due to the famous no-cloning theorem. Approximate cloning schemes have been proposed to achieve the optimal cloning characterized by the maximal fidelity between the…

Quantum Physics · Physics 2019-08-17 Xing Xiao , Yao Yao , Lei-Ming Zhou , Xiaoguang Wang

Several applications of quantum machine learning (QML) rely on a quantum measurement followed by training algorithms using the measurement outcomes. However, recently developed QML models, such as variational quantum circuits (VQCs), can be…

Quantum Physics · Physics 2023-08-31 Hossein T. Dinani , Diego Tancara , Felipe F. Fanchini , Ariel Norambuena , Raul Coto

We address the problem of optimal estimation of the relative phase for two-dimensional quantum systems in mixed states. In particular, we derive the optimal measurement procedures for an arbitrary number of qubits prepared in the same mixed…

Quantum Physics · Physics 2007-05-23 Giacomo Mauro D'Ariano , Chiara Macchiavello , Paolo Perinotti

Hybrid quantum systems in which acoustic resonators couple to superconducting qubits are promising quantum information platforms. High quality factors and small mode volumes make acoustic modes ideal quantum memories, while the qubit-phonon…

Quantum computers hold great promise to enhance machine learning, but their current qubit counts restrict the realisation of this promise. In an attempt to placate this limitation techniques can be applied for evaluating a quantum circuit…

Quantum Physics · Physics 2023-08-16 Simon C. Marshall , Casper Gyurik , Vedran Dunjko

In this work, we introduce a special kind of quantum cloning machine called Hybrid quantum cloning machine. The introduced Hybrid quantum cloning machine or transformation is nothing but a combination of pre-existing quantum cloning…

Quantum Physics · Physics 2011-11-09 Satyabrata Adhikari , A. K. Pati , Indranil Chakrabarty , B. S. Choudhury

We propose a scheme of continuous-variable reversible telecloning, which broadcast the information of an unknown state without loss from a sender to several spatially separated receivers exploiting multipartite entanglement as quantum…

Quantum Physics · Physics 2009-11-11 Jing Zhang , Changde Xie , Kunchi Peng

The variational quantum power method (VQPM), which adapts the classical power iteration algorithm for quantum settings, has shown promise for eigenvector estimation and optimization on quantum hardware. In this work, we provide a…

Quantum Physics · Physics 2026-01-26 Ammar Daskin

Accurate and efficient prediction of electronic wavefunctions is central to ab initio molecular dynamics (AIMD) and electronic structure theory. However, conventional ab initio methods require self-consistent optimization of electronic…

Chemical Physics · Physics 2025-11-12 Yanxian Tao , Lingyun Wan , Xiongzhi Zeng , Yingdi Jin , Jie Liu , Zhenyu Li , Jinlong Yang

A class of optimal quantum repeaters for qubits is suggested. The schemes are minimal, i.e. involve a single additional probe qubit, and optimal, i.e. provide the maximum information adding the minimum amount of noise. Information gain and…

Quantum Physics · Physics 2009-11-11 Marco G. Genoni , Matteo G. A. Paris