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A pulsed balanced homodyne detector has been developed for precise measurements of electric field quadratures of pulsed optical quantum states. A high level of common mode suppression (> 85 dB) and low electronic noise (730 electrons per…

Quantum Physics · Physics 2009-11-07 H. Hansen , T. Aichele , C. Hettich , P. Lodahl , A. I. Lvovsky , J. Mlynek , S. Schiller

Why do we need quantization to describe vision? What are the quadrature operators of the electromagnetic field? Is it possible to measure them? What are the characteristic functions useful for? In this brief tutorial we provide the…

Quantum Physics · Physics 2021-10-08 Stefano Olivares

Full reconstruction of quantum states from measurement samples is often a prohibitively complex task, both in terms of the experimental setup and the scaling of the sample size with the system. This motivates the relatively easier task of…

Quantum Physics · Physics 2025-08-04 Clara Wassner , Jack Davis , Sacha Cerf , Ulysse Chabaud , Francesco Arzani

We experimentally verify uncertainty relations for mixed states in the tomographic representation by measuring the radiation field tomograms, i.e. homodyne distributions. Thermal states of single-mode radiation field are discussed in…

Quantum Physics · Physics 2012-11-29 V. I. Man'ko , G. Marmo , A. Porzio , S. Solimeno , F. Ventriglia

In this work a quantum imaging setup based on undetected squeezed photons is employed for metrological applications such as sensitive phase measurement and quantum imaging. In spite of the traditional quantum imaging with undetected…

Quantum Physics · Physics 2025-06-10 S. Samimi , Z. Ghasemi , H. Mohammadi

We show that it is possible to use the spatial quantum correlations present in twin beams to extract information about the shape of a mask in the path of one of the beams. The scheme, based on noise measurements through homodyne detection,…

Quantum Physics · Physics 2015-06-04 A. M. Marino , J. B. Clark , Q. Glorieux , P. D. Lett

We propose a detection scheme for measuring the overlap of the quantum state of a weakly excited traveling-field mode with a desired reference quantum state, by successive mixing the signal mode with modes prepared in coherent states and…

Quantum Physics · Physics 2016-05-10 J. Clausen , M. Dakna , L. Knoll , D. -G. Welsch

The ability to engineer the quantum state of traveling optical fields is a central requirement for quantum information science and technology, including quantum communication, computing and metrology. In this video article, we describe the…

Quantum Physics · Physics 2014-07-02 Olivier Morin , Jianli Liu , Kun Huang , Felippe A. S. Barbosa , Claude Fabre , Julien Laurat

The generation of arbitrary single-mode quantum states from the vacuum by alternate coherent displacement and photon adding as well as the measurement of the overlap of a signal with an arbitrarily chosen quantum state are studied. With…

Quantum Physics · Physics 2016-05-17 J. Clausen , M. Dakna , L. Knoell , D. -G. Welsch

Conditional Measurement scheme which employs linear optical elements and photon detection is the fertile ground for nonclassical state generation. We consider a simple setup that requires a coherent state and a number state as inputs of the…

Quantum Physics · Physics 2024-12-30 Devibala Esakkimuthu , Basherrudin Mahmud Ahmed A

A new method is described for determining the quantum correlations at different times in optical pulses by using balanced homodyne detection. The signal pulse and sequences of ultrashort test pulses are superimposed, where for chosen…

Quantum Physics · Physics 2009-10-30 T. Opatrny , D. -G. Welsch , W. Vogel

In arXiv:2503.00188 we introduced broadband pulsed (BBP) homodyne measurements as a generalization of standard pulsed homodyne quadrature measurements. BBP can take advantage of detectors such as calorimeters that have the potential for…

Quantum Physics · Physics 2026-02-27 Emanuel Knill , Ezad Shojaee , James R. van Meter , Akira Kyle , Scott Glancy

Complete characterization of states and processes that occur within quantum devices is crucial for understanding and testing their potential to outperform classical technologies for communications and computing. However, solving this task…

Quantum Physics · Physics 2020-05-07 E. S. Tiunov , V. V. Tiunova , A. E. Ulanov , A. I. Lvovsky , A. K. Fedorov

We revisit the problem of quantum state reconstruction of light beams from the photocurrent quantum noise. As is well-known, but often overlooked, two longitudinal field modes contribute to each spectral component of the photocurrent…

We demonstrate that the task of determining an unknown quantum state can be accomplished efficiently by making a sequential measurement of two observables $\hat{A}$ and $\hat{B}$, provided that the two observables are chosen in such a way…

Quantum Physics · Physics 2013-10-22 Antonio Di Lorenzo

We investigate quantum measurement strategies capable of discriminating two coherent states probabilistically with significantly smaller error probabilities than can be obtained using non- probabilistic state discrimination. We apply a…

Quantum Physics · Physics 2010-10-12 Christoffer Wittmann , Ulrik L. Andersen , Masahiro Takeoka , Gerd Leuchs

In quantum information theory, the reliable and effective detection of entanglement is of paramount importance. However, given an unknown state, assessing its entanglement is a challenging task. To attack this problem, we investigate the…

Quantum Physics · Physics 2015-12-09 Jochen Szangolies , Hermann Kampermann , Dagmar Bruß

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

Gaussian quantum states hold special importance in the continuous variable (CV) regime. In quantum information science, the understanding and characterization of central resources such as entanglement may strongly rely on the knowledge of…

Quantum Physics · Physics 2015-07-21 A. S. Coelho , F. A. S. Barbosa , K. N. Cassemiro , M. Martinelli , A. S. Villar , P. Nussenzveig

Precision metrology underpins scientific and technological advancements. Quantum metrology offers a pathway to surpass classical sensing limits by leveraging quantum states and measurement strategies. However, measuring multiple…