QUROPE Quantum Information Processing and Communication in Europe

Author(s): Hong Lai, Josef Pieprzyk, and Lei Pan

Tensor networks offer a novel and powerful tool for solving a variety of problems in mathematics, data science, and engineering. One such network is the multiscale entanglement renormalization ansatz (MERA). The MERA exhibits a hierarchical structure of layers, where each layer corresponds to a part…

[Phys. Rev. A 106, 052403] Published Wed Nov 02, 2022

Author(s): He Wang, Liufang Xu, and Jin Wang

In this research we analyze two models using the tensor network algorithm. The quantum correlations of a two-qubit system are first studied in different bosonic reservoirs. Both equilibrium and nonequilibrium scenarios are discussed. Non-Markovian effects can improve the survival time of the quantum…

[Phys. Rev. A 106, 052404] Published Wed Nov 02, 2022

Author(s): Ma-Cheng Yang and Cong-Feng Qiao

A family of skew information quantities is obtained, in which the well-known Wigner-Yanase skew information and quantum Fisher information stand as special cases. A transparent proof of convexity of the generalized skew information is given, implying a simple proof of the Wigner-Yanase-Dyson conject…

[Phys. Rev. A 106, 052401] Published Tue Nov 01, 2022

Author(s): Rivu Gupta, Arghya Maity, Shiladitya Mal, and Aditi Sen(De)

The distribution of typical bipartite pure states is studied within the framework of state transformation via local operations and classical communication (LOCC). We report the statistics of comparable and incomparable states in different dimensions for single- and multicopy regimes, and we establis…

[Phys. Rev. A 106, 052402] Published Tue Nov 01, 2022

Author(s): D. A. Kronberg

The situation is studied when an ensemble of pure quantum states is mapped onto another ensemble of pure quantum states. In general, this operation may not be done with unit probability. In this work, the bounds for success probability of such operation are provided, with closed-form expressions inv…

[Phys. Rev. A 106, 042447] Published Mon Oct 31, 2022

Author(s): David Headley, Thorge Müller, Ana Martin, Enrique Solano, Mikel Sanz, and Frank K. Wilhelm

The quantum approximate optimization algorithm was proposed as a heuristic method for solving combinatorial optimization problems on near-term quantum computers and may be among the first algorithms to perform useful computations in the postsupremacy, noisy, intermediate-scale era of quantum computi…

[Phys. Rev. A 106, 042446] Published Fri Oct 28, 2022

Author(s): Wei Li and Shengmei Zhao

The ideal measurement-device-independent quantum key distribution (MDI-QKD), which is immune to all detector side-channel attacks, is built on the Bell state measurement of two single-photon states. However, in practical MDI-QKD where phase-randomized weak coherent pulses (PR-WCPs) are used, the mis…

[Phys. Rev. A 106, 042445] Published Fri Oct 28, 2022

Author(s): Michael Fellner, Anette Messinger, Kilian Ender, and Wolfgang Lechner

We demonstrate the applicability of a universal gate set in the parity encoding, which is a dual to the standard gate model, by exploring several quantum gate algorithms such as the quantum Fourier transform and quantum addition. Embedding these algorithms in the parity encoding reduces the circuit …

[Phys. Rev. A 106, 042442] Published Thu Oct 27, 2022

Author(s): Andrew Jena, Scott N. Genin, and Michele Mosca

Measuring the expectation value of Pauli operators on prepared quantum states is a fundamental task in a multitude of quantum algorithms. Simultaneously measuring sets of Pauli operators allows for fewer measurements and an overall speedup of the measurement process. Using results from coloring rand…

[Phys. Rev. A 106, 042443] Published Thu Oct 27, 2022

Author(s): Alexandru Paler

Quantum addition circuits are considered being of two types: (1) Toffoli-adder circuits which use only classical reversible gates (controlled-not and Toffoli), and (2) QFT-adder circuits based on the quantum Fourier transformation. We present a systematic translation of the QFT addition circuit into…

[Phys. Rev. A 106, 042444] Published Thu Oct 27, 2022

Author(s): John Hannegan, James D. Siverns, and Qudsia Quraishi

Future quantum networks will require the ability to produce matter-photon entanglement at photon frequencies not naturally emitted from the matter qubit. This allows for a hybrid network architecture, where these photons can couple to other tools and quantum technologies useful for tasks such as mul…

[Phys. Rev. A 106, 042441] Published Wed Oct 26, 2022

Author(s): V. Akshay, H. Philathong, E. Campos, D. Rabinovich, I. Zacharov, Xiao-Ming Zhang, and J. D. Biamonte

Variational quantum algorithms are the centerpiece of modern quantum programming. These algorithms involve training parametrized quantum circuits using a classical coprocessor, an approach adapted partly from classical machine learning. An important subclass of these algorithms, designed for combina…

[Phys. Rev. A 106, 042438] Published Tue Oct 25, 2022

Author(s): Subhankar Bera, Ananda G. Maity, Shiladitya Mal, and A. S. Majumdar

We explore the fundamental origin of the quantum advantage behind random access code. We propose new temporal inequalities compatible with noninvasive-realist models and show that any nonzero quantum advantage of n↦1 random access code in the presence of shared randomness is equivalent to the violat…

[Phys. Rev. A 106, 042439] Published Tue Oct 25, 2022

Author(s): Chengjie Zhang, Liangsheng Li, Guodong Lu, Haidong Yuan, and Runyao Duan

Most previous efforts on quantum error correction focused on either extending classical error-correction schemes to the quantum regime by performing a perfect correction on a subset of errors or seeking a recovery operation to maximize the fidelity between an input state and its corresponding output…

[Phys. Rev. A 106, 042440] Published Tue Oct 25, 2022

Author(s): Francesco Anna Mele, Ludovico Lami, and Vittorio Giovannetti

Is quantum communication possible over an optical fiber with transmissivity λ≤1/2? The answer is well known to be negative if the environment with which the incoming signal interacts is initialized in a thermal state. However, Lami et al. [Phys. Rev. Lett. 125, 110504 (2020)] found the quantum capac…

[Phys. Rev. A 106, 042437] Published Mon Oct 24, 2022

Author(s): Brij Mohan and Arun Kumar Pati

In the Schrödinger picture, the state of a quantum system evolves in time and the quantum speed limit describes how fast the state of a quantum system evolves from an initial state to a final state. However, in the Heisenberg picture the observable evolves in time instead of the state vector. Theref…

[Phys. Rev. A 106, 042436] Published Mon Oct 24, 2022

Author(s): Miao Cai and Keyu Xia (夏可宇)

Decoherence of a quantum system is one of the main difficulties for quantum information processing. Continuous dynamical decoupling has achieved great success in the improvement of the coherence of a quantum state but is difficult to optimize. Here we exploit the black-box optimization process in a …

[Phys. Rev. A 106, 042434] Published Fri Oct 21, 2022

Author(s): Donghong Han, Chu Guo, and Xiaoting Wang

Quantum state tomography is a key technique for quantum information processing but is challenging due to the exponential growth of its complexity with the system size. In this work we propose an algorithm which iteratively finds the best non-negative matrix product state approximation based on a set…

[Phys. Rev. A 106, 042435] Published Fri Oct 21, 2022

Author(s): Shubhayan Sarkar, Debashis Saha, and Remigiusz Augusiak

The authors propose a simple one-sided device-independent scheme for certification of any set of genuinely incompatible projective measurements, including mutually unbiased bases, and the maximally entangled state of two qudits.

[Phys. Rev. A 106, L040402] Published Fri Oct 21, 2022

Author(s): Shuai Liu, Ye-Hong Chen, Yu Wang, Yi-Hao Kang, Zhi-Cheng Shi, Jie Song, and Yan Xia

In this paper, we present an experimentally feasible protocol to generate the cat states in the microwave resonator coupled to a superconducting qubit. The setup employs a detuned, time-dependent parametric drive to squeeze the resonator mode so that an adjustable qubit-resonator coupling strength c…

[Phys. Rev. A 106, 042430] Published Thu Oct 20, 2022