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We show how group symmetries can be used to reconstruct quantum states. In our scheme for SU(1,1) states, the input field passes through a non-degenerate parametric amplifier and one measures the probability of finding the output state with…

Quantum Physics · Physics 2009-11-06 G. S. Agarwal , J. Banerji

We experimentally demonstrate the reconstruction of a photon number conditioned state without using a photon number discriminating detector. By using only phase randomized homodyne measurements, we reconstruct up to the three photon…

Quantum Physics · Physics 2021-07-28 H. M. Chrzanowski , S. M. Assad , Julien Bernu , Boris Hage , A. P. Lund , T. C. Ralph , P. K. Lam , T. Symul

The population distribution within the ground-state of an atomic ensemble is of large significance in a variety of quantum optics processes. We present a method to reconstruct the detailed population distribution from a set of absorption…

Quantum Physics · Physics 2010-06-04 P. London , O. Firstenberg , M. Shuker , A. Ron

Robust and reliable method for reconstructing quasi-distributions of integrated intensities of twin beams generated in spontaneous parametric down-conversion and entangled in photon numbers is suggested. It utilizes the first and second…

Quantum Physics · Physics 2015-06-12 Jan Perina , Ondrej Haderka , Vaclav Michalek , Martin Hamar

We formulate the density matrices of a quantum state obtained by first adding multi-photons to and then subtracting multi-photons from any arbitrary state as well as performing the same process in the reverse order. Considering the field to…

Quantum Physics · Physics 2023-04-12 Arpita Chatterjee

The image reconstruction of partially coherent light is interpreted as the quantum state reconstruction. The efficient method based on maximum-likelihood estimation is proposed to acquire information from registered intensity measurements…

Optics · Physics 2011-07-22 M. Jezek , Z. Hradil

We explore whether medium-resolution stellar spectra can be reconstructed from photometric observations, taking advantage of the highly compressible nature of the spectra. We formulate the spectral reconstruction as a least-squares problem…

Solar and Stellar Astrophysics · Physics 2015-05-19 A. Asensio Ramos , C. Allende Prieto

Experimental reconstructions of photon number distributions of both continuous-wave and pulsed light beams are reported. Our scheme is based on on/off avalanche photodetection assisted by maximum-likelihood estimation and does not involve…

Quantum Physics · Physics 2009-11-11 M. Bondani , G. Zambra , A. Andreoni , M. Gramegna , M. Genovese , G. Brida , A. Rossi , M. G. A. Paris

We realize on an Atom-Chip a practical, experimentally undemanding, tomographic reconstruction algorithm relying on the time-resolved measurements of the atomic population distribution among atomic internal states. More specifically, we…

New techniques based on weak measurements have recently been introduced to the field of quantum state reconstruction. Some of them allow the direct measurement of each matrix element of an unknown density operator and need only $O(d)$…

Quantum Physics · Physics 2019-01-31 Luca Calderaro , Giulio Foletto , Daniele Dequal , Paolo Villoresi , Giuseppe Vallone

We consider the problem of reconstructing a signal from under-determined modulo observations (or measurements). This observation model is inspired by a (relatively) less well-known imaging mechanism called modulo imaging, which can be used…

Machine Learning · Statistics 2019-07-18 Viraj Shah , Chinmay Hegde

We reconstruct a matrix product state (MPS) in reduced spaces using density matrix. This scheme applies to a MPS built on a blocked quantum lattice. Each block contains $N$ physical sites that have a local space of rank $R$. The simulation…

Strongly Correlated Electrons · Physics 2018-09-17 Lihua Wang , Kwang S. Kim

Generating dense physical fields from sparse measurements is a fundamental question in sampling, signal processing, and many other applications. State-of-the-art methods either use spatial statistics or rely on examples of dense fields in…

Machine Learning · Statistics 2026-01-29 Ofek Aloni , Barak Fishbain

We address the inverse problem of reconstructing both the structure and dynamics of a network from mean-field measurements, which are linear combinations of node states. This setting arises in applications where only a few aggregated…

Dynamical Systems · Mathematics 2025-11-04 Narcicegi Kiran , Tiago Pereira

I present a simple and robust method of quantum state reconstruction using non-ideal detectors able to distinguish only between presence and absence of photons. Using the scheme, one is able to determine a value of Wigner function in any…

Quantum Physics · Physics 2007-05-23 D. Mogilevtsev

We consider the method of infinite matrix inversion in the context of quantum state reconstruction. Using this method we give rigorous proofs for reconstruction formulas for the Cahill-Glauber s-parametrized distributions and the rotated…

Quantum Physics · Physics 2010-10-19 Jukka Kiukas , Juha-Pekka Pellonpää , Jussi Schultz

We discuss a scheme for reconstructing experimentally the diagonal elements of the density matrix of quantum optical states. Applications to PDC heralded photons, multi-thermal and attenuated coherent states are illustrated and discussed in…

Quantum Physics · Physics 2007-05-23 G. Brida , M. Genovese , M. Gramegna , M. G. A. Paris , E. Predazzi , E. Cagliero

We analyze the problem of reconstructing an unknown quantum state of a multipartite system from repeated measurements of local observables. In particular, via a system-theoretic observability analysis, we show that, even when the initial…

Quantum Physics · Physics 2025-09-23 Marco Peruzzo , Tommaso Grigoletto , Francesco Ticozzi

We describe in detail the theory underpinning the measurement of density matrices of a pair of quantum two-level systems (``qubits''). Our particular emphasis is on qubits realized by the two polarization degrees of freedom of a pair of…

Quantum Physics · Physics 2016-09-08 Daniel F. V. James , Paul G. Kwiat , William J. Munro , Andrew G. White

We present a method to reconstruct the complete statistical mode structure and optical losses of multimode conjugated optical fields using an experimentally measured joint photon-number probability distribution. We demonstrate that this…