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Photonic quantum technologies utilize various degrees of freedom (DOFs) of light, such as polarization, frequency, and spatial modes, to encode quantum information. In the effort of further improving channel capacity of quantum…

Quantum Physics · Physics 2026-04-30 Roey Shafran , Ron Ziv , Mordechai Segev

We present a formalism for self-calibrating tomography of arbitrary dimensional systems. Self-calibrating quantum state tomography was first introduced in the context of qubits, and allows the reconstruction of the density matrix of an…

Quantum Physics · Physics 2013-06-26 Nicolás Quesada , Agata M. Brańczyk , Daniel F. V. James

We present the theoretical basis for and experimental verification of arbitrary single-qubit state generation, using the polarization of photons generated via spontaneous parametric downconversion. Our precision measurement and state…

Quantum Physics · Physics 2007-05-23 Nicholas Peters , Joseph Altepeter , Evan Jeffrey , David Branning , Paul Kwiat

We investigate optimal discrimination between two projective single-qubit measurements in a scenario where the measurement can be performed only once. We consider general setting involving a tunable fraction of inconclusive outcomes and we…

Quantum Physics · Physics 2014-12-01 M. Mikova , M. Sedlak , I. Straka , M. Micuda , M. Ziman , M. Jezek , M. Dusek , J. Fiurasek

In this paper, we derive analytic expressions for the starting (initial) values of the parameters of the T-matrix that is frequently employed in the construction of a theoretical density matrix in a Maximum Likelihood Estimate (MLE)…

Quantum Physics · Physics 2014-07-25 Ramesh Bhandari

Quantum state tomography is an indispensable but costly part of many quantum experiments. Typically, it requires measurements to be carried in a number of different settings on a fixed experimental setup. The collected data is often…

Quantum Physics · Physics 2017-09-13 Jun Li , Shilin Huang , Zhihuang Luo , Keren Li , Dawei Lu , Bei Zeng

We discuss the tomography of $N$-qubit states using collective measurements. The method is exact for symmetric states, whereas for not completely symmetric states the information accessible can be arranged as a mixture of irreducible SU(2)…

Quantum Physics · Physics 2018-09-17 A. Muñoz , A. B. Klimov , M. Grassl , L. L. Sanchez-Soto

In contrast to the standard quantum state tomography, the direct tomography seeks the direct access to the complex values of the wave function at particular positions (i.e., the expansion coefficient in a fixed basis). Originally put…

Quantum Physics · Physics 2021-11-18 Xuan-Hoai Thi Nguyen , Mahn-Soo Choi

Quantum tomography is the main method used to assess the quality of quantum information processing devices, but its complexity presents a major obstacle for the characterization of even moderately large systems. The number of experimental…

Quantum Physics · Physics 2015-03-19 Marcus P. da Silva , Olivier Landon-Cardinal , David Poulin

We propose and test stable algorithms for the reconstruction of the internal conductivity of a biological object using acousto-electric measurements. Namely, the conventional impedance tomography scheme is supplemented by scanning the…

Analysis of PDEs · Mathematics 2015-05-20 Peter Kuchment , Leonid Kunyansky

Informationally complete measurements allow the estimation of expectation values of any operator on a quantum system, by changing only the data-processing of the measurement outcomes. In particular, an informationally complete measurement…

Quantum Physics · Physics 2007-05-23 G. M. D'Ariano , P. Perinotti , M. F. Sacchi

The characterization of a unitary gate is experimentally accomplished via Quantum Process Tomography, which combines the outcomes of different projective measurements to reconstruct the underlying operator. The process matrix is typically…

Quantum Physics · Physics 2025-09-17 Tareq Jaouni , Francesco Di Colandrea , Lorenzo Amato , Filippo Cardano , Ebrahim Karimi

Quantum state reconstruction based on weak continuous measurement has the advantage of being fast, accurate, and almost non-perturbative. In this work we present a pedagogical review of the protocol proposed by Silberfarb et al., PRL 95…

Quantum Physics · Physics 2015-05-20 Carlos A. Riofrío , Poul S. Jessen , Ivan H. Deutsch

We propose an efficient protocol to fully reconstruct a set of high-fidelity quantum gates. Usually, the efficiency of reconstructing high-fidelity quantum gates is limited by the sampling noise. Our protocol is based on a perturbative…

Quantum Physics · Physics 2021-03-24 Ruyu Yang , Ying Li

Characterizing complex quantum systems is a vital task in quantum information science. Quantum tomography, the standard tool used for this purpose, uses a well-designed measurement record to reconstruct quantum states and processes. It is,…

Quantum Physics · Physics 2015-12-10 Amir Kalev , Robert L. Kosut , Ivan H. Deutsch

Quantum state tomography is a key technique for quantum information processing, but is challenging due to the exponential growth of its complexity with the system size. In this work, we propose an algorithm which iteratively finds the best…

Quantum Physics · Physics 2022-05-13 Donghong Han , Chu Guo , Xiaoting Wang

Quantum information protocols often rely on tomographic techniques to determine the state of the system. A popular method of encoding information is on the different paths a photon may take, for example, parallel waveguides in integrated…

Quantum Physics · Physics 2019-06-11 Davor Curic , Lambert Giner , Jeff S. Lundeen

Using a spontaneous parametric-downconversion source of photon pairs, we are working towards the creation of arbitrary 2-qubit quantum states with high fidelity. Currently, all physically allowable combinations of polarization entanglement…

Quantum Physics · Physics 2007-05-23 Paul Kwiat , Joe Altepeter , David Branning , Evan Jeffrey , Nicholas Peters , Tzu-Chieh Wei

It has been recently shown that a state generated by a one-dimensional noisy quantum computer is well approximated by a matrix product operator with a finite bond dimension independent of the number of qubits. We show that full quantum…

Quantum Physics · Physics 2022-07-14 Alexander Lidiak , Casey Jameson , Zhen Qin , Gongguo Tang , Michael B. Wakin , Zhihui Zhu , Zhexuan Gong

We present a quantum state tomography method that enables the reconstruction of \emph{arbitrary} $d-$dimensional quantum states encoded in the discretized transverse momentum of photons, by using \emph{only} $d+1$ experimental settings. To…

Quantum Physics · Physics 2025-06-23 Quimey Pears Stefano , Lorena Rebón , Claudio Iemmi