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Related papers: Saturating the quantum Cram\'er-Rao bound using LO…

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Single-qubit measurements are typically insufficient for inferring arbitrary quantum states of a multi-qubit system. We show that if the system can be fully controlled by driving a single qubit, then utilizing a local random pulse is almost…

Quantum Physics · Physics 2020-01-14 Pengcheng Yang , Min Yu , Ralf Betzholz , Christian Arenz , Jianming Cai

In a recent paper \cite{mySEPvsLOCC}, we showed how to construct a quantum protocol for implementing a bipartite, separable quantum measurement using only local operations on subsystems and classical communication between parties (LOCC)…

Quantum Physics · Physics 2014-08-07 Scott M. Cohen

Quantum fluctuations in the intensity of an optical probe is noise which limits measurement precision in absorption spectroscopy. Increased probe power can offer greater precision, however, this strategy is often constrained by sample…

Quantum Physics · Physics 2021-11-29 J. Biele , S. Wollmann , J. W. Silverstone , J. C. F. Matthews , E. J. Allen

Quantum state tomography seeks to reconstruct an unknown state from measurement statistics. A finite measurement (POVM) is \emph{pure-state informationally complete} (PSI-Complete) if the outcome probabilities determine any pure state up to…

Quantum Physics · Physics 2025-11-13 Dan Edidin , Ivan Gonzalez , Itzhak Tamo

Quantum reservoir computing (QRC) is a hardware-implementation-friendly quantum neural network scheme with minimal physical system requirements and a proven advantage over classical counterparts. We use an extension of the positive-P phase…

Quantum Physics · Physics 2026-03-19 S. Świerczewski , W. Verstraelen , P. Deuar , T. C. H. Liew , A. Opala , M. Matuszewski

A usual assumption in quantum estimation is that the unknown parameter labels the possible states of the system, while it influences neither the sample space of outcomes nor the measurement aimed at extracting information on the parameter…

Quantum Physics · Physics 2017-01-18 Luigi Seveso , Matteo A. C. Rossi , Matteo G. A. Paris

The reconstruction of quantum states from experimental measurements, often achieved using quantum state tomography (QST), is crucial for the verification and benchmarking of quantum devices. However, performing QST for a generic…

Quantum Physics · Physics 2024-10-07 Zhen Qin , Casey Jameson , Zhexuan Gong , Michael B. Wakin , Zhihui Zhu

We show that the quantum Cram\'er-Rao bound on the precision of measurements of the optical phase gradient, or the wavefront tilt, with a beam of finite width is consistent with the Heisenberg uncertainty principle for a single-photon…

Quantum Physics · Physics 2020-07-22 Walker Larson , Bahaa E. A. Saleh

Every measurement that can be implemented by local quantum operations and classical communication (LOCC) using an infinite number of rounds is the limit of a sequence of measurements each of which requires only a finite number of rounds.…

Quantum Physics · Physics 2014-10-14 Scott M. Cohen

Current quantum computers have the potential to overcome classical computational methods, however, the capability of the algorithms that can be executed on noisy intermediate-scale quantum devices is limited due to hardware imperfections.…

Quantum Physics · Physics 2023-08-16 Cristian A. Galvis-Florez , Daniel Reitzner , Simo Särkkä

In this paper we study the subset of generalized quantum measurements on finite dimensional systems known as local operations and classical communication (LOCC). While LOCC emerges as the natural class of operations in many important…

Quantum Physics · Physics 2014-05-14 Eric Chitambar , Debbie Leung , Laura Mancinska , Maris Ozols , Andreas Winter

We consider generic pure $n$-qubit states and a general class of pure states of arbitrary dimensions and arbitrarily many subsystems. We characterize those states which can be reached from some other state via Local Operations assisted by…

Quantum Physics · Physics 2017-02-01 C. Spee , J. I. de Vicente , D. Sauerwein , B. Kraus

Assuming that the parameter dependent evolution, as well as the measurements that are done for readout, of a quantum system that acts as the probe in a quantum limited measurement scheme are both fixed, we find the optimal initial states of…

Quantum Physics · Physics 2015-06-12 Salini Jose , Noufal Jaseem , Anil Shaji

Tomography of a quantum state is usually based on positive operator-valued measure (POVM) and on their experimental statistics. Among the available reconstructions, the maximum-likelihood (MaxLike) technique is an efficient one. We propose…

We present a method of determining important properties of a shared bipartite quantum state, within the ``distant labs'' paradigm, using \emph{only} local operations and classical communication (LOCC). We apply this procedure to spectrum…

Quantum Physics · Physics 2007-05-23 Carolina Moura Alves , Pawel Horodecki , Daniel K. L. Oi , L. C. Kwek , Artur K. Ekert

Constructing an integrated large-scale qubit system of realistic size requires addressing the challenge of physical crowding among qubits. This constraint poses an issue of coarse-grained (CG) measurement, wherein information from the…

Quantum Physics · Physics 2024-04-10 Donghun Jung , Young-Wook Cho , Yosep Kim , Junghyun Lee

It is challenged only recently that the precision attainable in any measurement of a physical parameter is fundamentally limited by the quantum Cram\'{e}r-Rao Bound (QCRB). Here, targeting at measuring parameters in strongly dissipative…

Quantum Physics · Physics 2020-07-08 Da-Jian Zhang , Jiangbin Gong

We present a new proof of the quantum Cramer-Rao bound for precision parameter estimation [1-3] and extend it to a more general class of measurement procedures. We analyze a generalized framework for parameter estimation that covers most…

Quantum Physics · Physics 2010-01-28 Garry Goldstein , Mikhail D. Lukin , Paola Cappellaro

Quantum mechanics offers the possibility of unconditionally secure communication between multiple remote parties. Security proofs for such protocols typically rely on bounding the capacity of the quantum channel in use. In a similar manner,…

Device-independent (DI) quantum protocols exploit Bell inequality violations to ensure security or certify quantum properties without making assumptions about the internal workings of the devices. In this work, we study the role of rank-one…