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I propose an approach to adaptive homodyne detection of digitally modulated quantum optical pulses in which the phase of the local oscillator is chosen to maximize the average information gain, i.e., the mutual information, at each step of…

Quantum Physics · Physics 2007-05-23 Igor Bargatin

We present an experimental demonstration of the power of real-time feedback in quantum metrology, confirming a theoretical prediction by Wiseman regarding the superior performance of an adaptive homodyne technique for single-shot…

Quantum Physics · Physics 2007-05-23 Michael A. Armen , John K. Au , John K. Stockton , Andrew C. Doherty , Hideo Mabuchi

Balanced homodyning, heterodyning and unbalanced homodyning are the three well-known sampling techniques used in quantum optics to characterize all possible photonic sources in continuous-variable quantum information theory. We show that…

Quantum Physics · Physics 2019-07-31 Yong Siah Teo , Hyunseok Jeong , Luis L. Sanchez-Soto

We address measurements of covariant phase observables (CPOs) by means of realistic eight-port homodyne detectors. We do not assume equal quantum efficiencies for the four photodetectors and investigate the conditions under which the…

Quantum Physics · Physics 2013-05-29 Juha-Pekka Pellonpää , Jussi Schultz , Matteo G. A. Paris

We theoretically identify observable consequences of spatial and spin symmetries on the dynamics of a small XXZ quantum simulator. Our proposed protocol relies on the choice of suitable initial states, and involves the measurement scheme…

Quantum Physics · Physics 2026-04-08 D. J. Papoular

Quantum synchronization has been a central topic in quantum nonlinear dynamics. Despite rapid development in this field, very few have studied how to efficiently boost synchronization. Homodyne measurement emerges as one of the successful…

Quantum Physics · Physics 2023-08-08 Yuan Shen , Hong Yi Soh , Weijun Fan , Leong-Chuan Kwek

We estimate the quantum state of a light beam from results of quantum homodyne measurements performed on identically prepared pulses. The state is represented through the Wigner function, a ``quasi-probability density'' on $\mathbb{R}^{2}$…

Statistics Theory · Mathematics 2011-06-23 Madalin Guta , Luis Artiles

We study quantum measurement with preselection and postselection, and derive the precise expressions of the measurement results without any restriction on the coupling strength between the system and the measuring device. For a qubit…

Quantum Physics · Physics 2011-11-18 Xuanmin Zhu , Yuxiang Zhang , Shengshi Pang , Chang Qiao , Quanhui Liu , Shengjun Wu

We develop the theoretical tools necessary to promote electro-optic sampling to a time-domain quantum tomography technique. Our proposed framework implements detection of the time evolution of both the electric-field of a propagating…

Quantum Physics · Physics 2023-07-26 Sho Onoe , Stéphane Virally , Denis V. Seletskiy

We present a scheme by which projective homodyne measurement of a microwave resonator can be used to generate entanglement between two superconducting charge qubits coupled to this resonator. The non-interacting qubits are initialised in a…

Quantum Physics · Physics 2009-09-29 D. A. Rodrigues , C. E. A. Jarvis , B. L. Györffy , T. P. Spiller , J. F. Annett

We discuss a balanced homodyne detection scheme with imperfect detectors in the framework of the operational approach to quantum measurement. We show that a realistic homodyne measurement is described by a family of operational observables…

atom-ph · Physics 2009-10-28 Konrad Banaszek , Krzysztof Wodkiewicz

We study the discrimination of N mixed quantum states in an optimal measurement that maximizes the probability of correct results while the probability of inconclusive results is fixed at a given value. After considering the discrimination…

Quantum Physics · Physics 2015-06-11 Ulrike Herzog

We present a method of measuring expectation values of quadrature moments of a multimode field through two-level probe ``homodyning''. Our approach is based on an integral transform formalism of measurable probe observables, where…

Quantum Physics · Physics 2009-11-11 P. Lougovski , H. Walther , E. Solano

We derive an optimal bound on the sum of entropic uncertainties of two or more observables when they are sequentially measured on the same ensemble of systems. This optimal bound is shown to be greater than or equal to the bounds derived in…

Quantum Physics · Physics 2009-11-07 M. D. Srinivas

We investigate generalized measurements, based on positive-operator-valued measures, and von Neumann measurements for the unambiguous discrimination of two mixed quantum states that occur with given prior probabilities. In particular, we…

Quantum Physics · Physics 2009-11-11 Ulrike Herzog , Janos A. Bergou

We explore the possibility of achieving optimal joint measurements of noncommuting observables on a single quantum system by performing conventional measurements of commuting self adjoint operators on optimal clones of the original quantum…

Quantum Physics · Physics 2009-11-06 G. M. D'Ariano , C. Macchiavello , M. F. Sacchi

The distribution of measured values for maximally accurate, unbiased simultaneous measurements of position and momentum is investigated. It is shown, that if the measurement is retrodictively optimal, then the distribution of results is…

Quantum Physics · Physics 2007-05-23 D. M. Appleby

We present a family of entropic uncertainty relations for pointer-based simultaneous measurements of conjugate observables. The lower bounds of these relations explicitly incorporate the influence of the measurement apparatus. We achieve…

Quantum Physics · Physics 2013-01-28 Raoul Heese , Matthias Freyberger

Characterizing noisy quantum devices requires methods for learning the underlying quantum Hamiltonian which governs their dynamics. Often, such methods compare measurements to simulations of candidate Hamiltonians, a task which requires…

Quantum Physics · Physics 2021-10-13 Assaf Zubida , Elad Yitzhaki , Netanel H. Lindner , Eyal Bairey

The fields of precision timekeeping and spectroscopy increasingly rely on optical frequency comb interferometry. However, comb-based measurements are not described by existing quantum theory because they exhibit both large mode mismatch and…

Quantum Physics · Physics 2024-04-02 Noah Lordi , Eugene J. Tsao , Alexander J. Lind , Scott A. Diddams , Joshua Combes