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Non Gaussian states and processes are useful resources in quantum information with continuous variables. An experimentally accessible criterion has been proposed to measure the degree of non Gaussianity of quantum states, based on the…

We introduce the concept of quantum field tomography, the efficient and reliable reconstruction of unknown quantum fields based on data of correlation functions. At the basis of the analysis is the concept of continuous matrix product…

Quantum Physics · Physics 2015-06-22 A. Steffens , C. A. Riofrío , R. Hübener , J. Eisert

We propose to experimentally test the nonclassicality of quantum states through homodyne tomography. For single-mode states we check violations of inequalities involving the photon-number probability. For two-mode states we test the…

Quantum Physics · Physics 2009-10-31 G. M. D'Ariano , M. F. Sacchi , P. Kumar

We describe a novel tool for the quantum characterization of optical devices. The experimental setup involves a stable reference state that undergoes an unknown quantum transformation and is then revealed by balanced homodyne detection.…

The accuracy in determining the quantum state of a system depends on the type of measurement performed. Homodyne and heterodyne detection are the two main schemes in continuous-variable quantum information. The former leads to a direct…

In this work we introduce a general scheme for measurement based quantum computation in continuous variables. Our approach does not necessarily rely on the use of ancillary cluster states to achieve its aim, but rather on the detection of a…

Quantum Physics · Physics 2017-02-01 Giulia Ferrini , Jonathan Roslund , Francesco Arzani , Claude Fabre , Nicolas Treps

A major bottleneck in the quest for scalable many-body quantum technologies is the difficulty in benchmarking their preparations, which suffer from an exponential `curse of dimensionality' inherent to their quantum states. We present an…

Quantum Physics · Physics 2019-07-31 Juan Carrasquilla , Giacomo Torlai , Roger G. Melko , Leandro Aolita

Continuous-Variable (CV) devices are a promising platform for demonstrating large-scale quantum information protocols. In this framework, we define a general quantum computational model based on a CV hardware. It consists of vacuum input…

Quantum Physics · Physics 2019-02-06 Tom Douce , Damian Markham , Elham Kashefi , Peter van Loock , Giulia Ferrini

Conventionally, unknown quantum states are characterized using quantum-state tomography based on strong or weak measurements carried out on an ensemble of identically prepared systems. By contrast, the use of protective measurements offers…

Quantum Physics · Physics 2016-01-25 Maximilian Schlosshauer

The reconstruction of density matrices from measurement data (quantum state tomography) is the most comprehensive method for assessing the accuracy and performance of quantum devices. Existing methods to reconstruct two-photon density…

Quantum Physics · Physics 2025-03-12 Salini Rajeev , Mayukh Lahiri

In quantum information transformation and quantum computation, the most critical issues are security and accuracy. These features, therefore, stimulate research on quantum state characterization. A characterization tool, Quantum state…

Quantum Physics · Physics 2023-06-01 Xudan Chai , Teng Ma , Qihao Guo , Zhangqi Yin , Hao Wu , Qing Zhao

Quantum state tomography (QST) is the process of reconstructing the state of a quantum system (mathematically described as a density matrix) through a series of different measurements, which can be solved by learning a parameterized…

Quantum Physics · Physics 2025-03-31 Hailan Ma , Zhenhong Sun , Daoyi Dong , Chunlin Chen , Herschel Rabitz

We present a method for quantum state tomography that enables the efficient estimation, with fixed precision, of any of the matrix elements of the density matrix of a state, provided that the states from the basis in which the matrix is…

Quantum Physics · Physics 2015-06-12 Ariel Bendersky , Juan Pablo Paz

Bosonic fault tolerant quantum computing requires preparations of Bosonic code states like cat states and GKP states with high fidelity and reliable quantum certification of these states. Although many proposals on preparing these states…

Quantum Physics · Physics 2022-12-01 Ya-Dong Wu

Continuous variable quantum state tomography is one of the most powerful techniques to study the properties of light fields in quantum optics. However, the need for a fixed phase reference has so far prevented widespread usage in other…

Optics · Physics 2020-02-24 Johannes Thewes , Carolin Lüders , Marc Aßmann

Entanglement in continuous-variable non-Gaussian states provides irreplaceable advantages in many quantum information tasks. However, the sheer amount of information in such states grows exponentially and makes a full characterization…

We suggest a general scheme for quantum state engineering based on conditional measurements carried out on entangled twin-beam of radiation. Realistic detection schemes such as {\sc on/off} photodetection, homodyne detection and joint…

Quantum Physics · Physics 2009-11-07 Matteo G. A. Paris , Mary Cola , Rodolfo Bonifacio

Boson sampling is a sub-universal model used to show quantum speed-up. However, the methods of validation to prove quantum speedup are not robust and accurate. All verification methods involve additional or little studied assumptions. Here,…

We present \texttt{lcg\_plus}, an open-source Python library for the simulation of continuous-variable quantum circuits with both generaldyne and photon-number-resolving detector capabilities. Our framework merges the linear combination of…

Quantum Physics · Physics 2025-08-11 Olga Solodovnikova , Ulrik L. Andersen , Jonas S. Neergaard-Nielsen

Continuous-variable (CV) quantum key distribution (QKD) employs the quadratures of a bosonic mode to establish a secret key between two remote parties, and this is usually achieved via a Gaussian modulation of coherent states. The resulting…