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Any optical quantum information processing machine would be comprised of fully-characterized constituent devices for both single state manipulations and tasks involving the interaction between multiple quantum optical states. Ideally for…

Quantum Physics · Physics 2015-05-18 Connor Kupchak , Samuel Rind , Bertus Jordaan , Eden Figueroa

Classical electromagnetic fields and quantum mechanics -- both obey the principle of superposition alike. This opens up many avenues for simulation of a large variety of phenomena and algorithms, which have hitherto been considered quantum…

Quantum Physics · Physics 2021-12-07 Sooryansh Asthana , V. Ravishankar

Quantum computing using two optical coherent states as qubit basis states has been suggested as an interesting alternative to single photon optical quantum computing with lower physical resource overheads. These proposals have been…

Quantum Physics · Physics 2009-11-13 A. P. Lund , T. C. Ralph , H. L. Haselgrove

In this paper a programmable quantum state discriminator is implemented by using nuclear magnetic resonance. We use a two qubit spin-1/2 system, one for the data qubit and one for the ancilla (programme) qubit. This device does the…

Quantum Physics · Physics 2009-11-11 T. Gopinath , Ranabir Das , Anil Kumar

The quantum states of two laser pulses---coherent states---are never mutually orthogonal, making perfect discrimination impossible. Even so, coherent states can achieve the ultimate quantum limit for capacity of a classical channel, the…

Quantum Physics · Physics 2015-03-19 Jian Chen , Jonathan L. Habif , Zachary Dutton , Richard Lazarus , Saikat Guha

We demonstrate a coherent quantum measurement for the determination of the degree of polarization (DOP). This method allows to measure the DOP in the presence of fast polarization state fluctuations, difficult to achieve with the typically…

Quantum Physics · Physics 2009-11-10 M. Legre , M. Wegmuller , N. Gisin

A fundamental problem in Quantum Information Processing is the discrimination amongst a set of quantum states of a system. In this paper, we address this problem on an open quantum system described by a graph, whose evolution is defined by…

Quantum Physics · Physics 2020-10-07 Nicola Dalla Pozza , Filippo Caruso

A basic feasible probabilistic purification of unknown noisy coherent states, outgoing from different state preparations with unknown mean number of thermal photons, is proposed. The scheme is based only on a linear-optical network with an…

Quantum Physics · Physics 2007-06-14 Petr Marek , Radim Filip

We put the pure-state decomposition mathematical property of a mixed state to a physical test. We begin by characterizing all the possible decompositions of a rank-two mixed state by means of the complex overlap between two involved states.…

Quantum Physics · Physics 2015-05-20 Luis Roa , Alejandra Maldonad-Trapp , Marcelo Alid

The problem addressed is to design a detector which is maximally sensitive to specific quantum states. Here we concentrate on quantum state detection using the worst-case a posteriori probability of detection as the design criterion. This…

Quantum Physics · Physics 2007-05-23 Robert L. Kosut , Ian Walmsley , Yonina Eldar , Herschel Rabitz

In this paper, we investigate the problem of estimating the phase of a coherent state in the presence of unavoidable noisy quantum states. These unwarranted quantum states are represented by outlier quantum states in this study. We first…

Quantum Physics · Physics 2020-08-06 Yukito Mototake , Jun Suzuki

It is a well-known fact that the optimal POVM for quantum state tomography is the symmetric, informationally complete, positive operator valued measure (SIC-POVM). We investigate the same problem only in the case when there are some a…

Quantum Physics · Physics 2015-11-23 Dénes Petz , László Ruppert

Quantum state discrimination is a fundamental concept in quantum information theory, which refers to a class of techniques to identify a specific quantum state through a positive operator-valued measure. In this work, we investigate how…

Quantum Physics · Physics 2025-07-09 Hyunho Cha , Jungwoo Lee

Quantum mechanics forbids deterministic discrimination among non-orthogonal states. Nonetheless, the capability to distinguish nonorthogonal states unambiguously is an important primitive in quantum information processing. In this work, we…

Quantum Physics · Physics 2016-08-16 Masoud Mohseni , Aephraim M. Steinberg , János A. Bergou

When comparing quantum states to each other, it is possible to obtain an unambiguous answer, indicating that the states are definitely different, already after a single measurement. In this paper we investigate comparison of coherent…

Quantum Physics · Physics 2007-05-23 Erika Andersson , Marcos Curty , Igor Jex

We investigate the possibility of implementing a given projection measurement using linear optics and arbitrarily fast feedforward based on the continuous detection of photons. In particular, we systematically derive the so-called Dolinar…

Quantum Physics · Physics 2009-11-10 Masahiro Takeoka , Masahide Sasaki , Peter van Loock , Norbert Lütkenhaus

We describe a general quantum receiver protocol that maps laser-light-modulated classical communications signals into quantum processors for decoding with quantum logic. The quantum logic enables joint quantum measurements over a codeword…

Quantum Physics · Physics 2026-03-16 Kelly Werker Smith , Don Boroson , Saikat Guha , Johannes Borregaard

We introduce a set of coherent states which are associated with quantum systems governed by a trilinear boson Hamiltonian. These states are produced by the action of a nonunitary displacement operator on a reference state and can be…

Quantum Physics · Physics 2009-10-30 C. Brif

With the purpose to introduce a useful tool for researches concerning foundations of quantum mechanics and applications to quantum technologies, here we study three quantumness quantifiers for bipartite optical systems: one based on…

Quantum Physics · Physics 2011-06-13 G. Brida , M. Bondani , I. P. Degiovanni , M. Genovese , M. G. A. Paris , I. Ruo Berchera , V. Schettini

Suppose you receive a sequence of qubits where each qubit is guaranteed to be in one of two pure states, but you do not know what those states are. Your task is to determine the states. This can be viewed as a kind of quantum state learning…