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We consider a protocol to perform the optimal quantum state discrimination of $N$ linearly independent non-orthogonal pure quantum states and present a computational code. Through the extension of the original Hilbert space, it is possible…

Quantum Physics · Physics 2016-09-08 Wilson R. M. Rabelo , Alexandre G. Rodrigues , Reinaldo O. Vianna

Model-independent estimation of the properties of quantum states is a central challenge in quantum technologies, as experimental imperfections, drifts, and imprecise models of the actual quantum dynamics inevitably hinder accurate…

The orbital angular momentum (OAM) of photons is a promising degree of freedom for high-dimensional quantum key distribution (QKD). However, effectively mitigating the adverse effects of atmospheric turbulence is a persistent challenge in…

Signal Processing · Electrical Eng. & Systems 2020-06-24 Jiapeng Zhao , Yiyu Zhou , Boris Braverman , Cong Liu , Kai Pang , Nicholas K. Steinhoff , Glenn A. Tyler , Alan E. Willner , Robert W. Boyd

Adaptive techniques make practical many quantum measurements that would otherwise be beyond current laboratory capabilities. For example: they allow discrimination of nonorthogonal states with a probability of error equal to the Helstrom…

Quantum Physics · Physics 2009-12-15 H. M. Wiseman , D. W. Berry , S. D. Bartlett , B. L. Higgins , G. J. Pryde

Quantum computers are inherently affected by noise. While in the long-term error correction codes will account for noise at the cost of increasing physical qubits, in the near-term the performance of any quantum algorithm should be tested…

Multi-photon quantum interference is the underlying principle for optical quantum information processing protocols. Indistinguishability is the key to quantum interference. Therefore, the success of many protocols in optical quantum…

Quantum Physics · Physics 2020-09-23 Liang Cui , Jie Su , Jiamin Li , Yuhong Liu , Xiaoying Li , Z. Y. Ou

We are concerned with numerical simulations of quantum optical circuits under certain realistic conditions, specifically that photon quantum states are not perfectly indistinguishable. The partial photon distinguishability presents a…

Quantum Physics · Physics 2023-07-14 Javier Osca , Jiri Vala

Existing algorithms for the optimal control of quantum observables are based on locally optimal steps in the space of control fields, or as in the case of genetic algorithms, operate on the basis of heuristics that do not explicitly take…

Quantum Physics · Physics 2007-08-27 Raj Chakrabarti , Rebing Wu , Herschel Rabitz

Orbital angular momentum (OAM) detection underpins almost all aspects of vortex beams' advances such as communication and quantum analogy. Conventional schemes are frustrated by low speed, complicated system, limited detection range. Here,…

Emerging Technologies · Computer Science 2022-09-07 Hao Wang , Ziyu Zhan , Futai Hu , Yuan Meng , Zeqi Liu , Xing Fu , Qiang Liu

Accurately estimating high-order moments of quantum states is an elementary precondition for many crucial tasks in quantum computing, such as entanglement spectroscopy, entropy estimation, spectrum estimation, and predicting non-linear…

Quantum Physics · Physics 2024-05-16 Benchi Zhao , Mingrui Jing , Lei Zhang , Xuanqiang Zhao , Yu-Ao CHen , Kun Wang , Xin Wang

Quantum phase estimation is a paradigmatic problem in quantum sensing andmetrology. Here we show that adaptive methods based on classical machinelearning algorithms can be used to enhance the precision of quantum phase estimation when noisy…

Quantum Physics · Physics 2021-09-01 Nelson Filipe Costa , Yasser Omar , Aidar Sultanov , Gheorghe Sorin Paraoanu

Estimation of quantum states and measurements is crucial for the implementation of quantum information protocols. The standard method for each is quantum tomography. However, quantum tomography suffers from systematic errors caused by…

Quantum Physics · Physics 2018-10-19 Adam C. Keith , Charles H. Baldwin , Scott Glancy , E. Knill

Reconstructing the state of a complex quantum system represents a pivotal task for all quantum information applications, both for characterization purposes and for verification of quantum protocols. Recent technological developments have…

Quantum state learning is a fundamental problem in physics and computer science. As near-term quantum devices are error-prone, it is important to design error-resistant algorithms. Apart from device errors, other unexpected factors could…

Quantum Physics · Physics 2025-08-20 Maryam Aliakbarpour , Vladimir Braverman , Nai-Hui Chia , Yuhan Liu

Quantum Key Distribution (QKD) guarantees the security of communication with quantum physics. Most of widely adopted QKD protocols currently encode the key information with binary signal format---qubit, such as the polarization states.…

Quantum Physics · Physics 2018-01-23 Fumin Wang , Pei Zeng , Xiaoli Wang , Hong Gao , Fuli Li , Pei Zhang

Entangled photons are widely used in quantum technologies. Many photonic experiments generate them with probabilistic photon-pair sources that can be modeled as squeeze operators. In practice, these sources are usually treated in the…

Quantum Physics · Physics 2026-05-05 Carlos Ruiz-Gonzalez , Mario Krenn , Xuemei Gu

Variational algorithms are promising candidates to be implemented on near-term quantum computers. The variational quantum eigensolver (VQE) is a prominent example, where a parametrized trial state of the quantum mechanical wave function is…

Quantum noise constitutes a fundamental obstacle to realizing practical quantum technologies. To address the pivotal challenge of identifying quantum systems least affected by noise, we introduce the purest quantum state identification,…

Quantum Physics · Physics 2025-09-24 Yingqi Yu , Honglin Chen , Jun Wu , Wei Xie , Xiangyang Li

Quantum state preparation involves preparing a target state from an initial system, a process integral to applications such as quantum machine learning and solving systems of linear equations. Recently, there has been a growing interest in…

Quantum Physics · Physics 2024-05-08 Shuwen Kan , Miguel Palma , Zefan Du , Samuel A Stein , Chenxu Liu , Juntao Chen , Ang Li , Ying Mao

We show that optimal control of the electron dynamics is able to prepare molecular ground states, within chemical accuracy, with evolution times approaching the bounds imposed by quantum mechanics. We propose a specific parameterization of…

Quantum Physics · Physics 2024-02-20 Davide Castaldo , Marta Rosa , Stefano Corni