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Large-scale structure distorts the images of background galaxies, which allows one to measure directly the projected distribution of dark matter in the universe and determine its power spectrum. Here we address the question of how to…

Astrophysics · Physics 2009-10-30 Uros Seljak

To improve the efficiency of the state tomography strategy via weak value, we have searched the optimal coupling strength between the system and measuring device. For an arbitrary d-dimensional quantum system, the optimal strengths being…

Quantum Physics · Physics 2024-02-23 Xuanmin Zhu , Dezheng Zhang , Runping Gao , Qun wei , Lixia Liu , Zijiang Luo

We introduce two methods for estimating the density matrix for a quantum system: Quantum Maximum Likelihood and Quantum Variational Inference. In these methods, we construct a variational family to model the density matrix of a mixed…

Quantum Physics · Physics 2019-04-15 Kyle Cranmer , Siavash Golkar , Duccio Pappadopulo

We introduce a versatile and practical framework for applying matrix product state techniques to continuous quantum systems. We divide space into multiple segments and generate continuous basis functions for the many-body state in each…

Quantum Gases · Physics 2022-06-09 Shovan Dutta , Anton Buyskikh , Andrew J. Daley , Erich J. Mueller

Within the framework of linear elasticity we assume the availability of internal full-field measurements of the continuum deformations of a non-homogeneous isotropic solid. The aim is the quantitative reconstruction of the associated…

Analysis of PDEs · Mathematics 2015-06-17 Guillaume Bal , Cédric Bellis , Sébastien Imperiale , François Monard

Compressive sensing is a methodology for the reconstruction of sparse or compressible signals using far fewer samples than required by the Nyquist criterion. However, many of the results in compressive sensing concern random sampling…

Numerical Analysis · Mathematics 2014-04-02 Guangliang Chen , Atul Divekar , Deanna Needell

Estimation of quantum states is one of the most important steps in any quantum information processing experiment. A naive reconstruction of the density matrix from experimental measurements can often give density matrices which are not…

Quantum Physics · Physics 2016-08-24 Harpreet Singh , Arvind , Kavita Dorai

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

In this paper we study the reconstruction of binary sparse signals from partial random circulant measurements. We show that the reconstruction via the least-squares algorithm is as good as the reconstruction via the usually used program…

Information Theory · Computer Science 2020-06-29 Sandra Keiper

We consider the problem of finding a sparse solution for an underdetermined linear system of equations when the known parameters on both sides of the system are subject to perturbation. This problem is particularly relevant to…

Systems and Control · Computer Science 2016-06-16 Reza Arablouei

Quantum state reconstruction involves measurement devices that are usually described by idealized models, but not known in full detail in experiments. For weak propagating microwaves, the detection process requires linear amplifiers which…

Mesoscale and Nanoscale Physics · Physics 2010-09-06 E. P. Menzel , F. Deppe , M. Mariantoni , M. Á. Araque Caballero , A. Baust , T. Niemczyk , E. Hoffmann , A. Marx , E. Solano , R. Gross

In some cases the state of a quantum system with a large number of subsystems can be approximated efficiently by the density matrix renormalization group, which makes use of redundancies in the description of the state. Here we show that…

Strongly Correlated Electrons · Physics 2009-02-03 Michael J. Hartmann , Javier Prior , Stephen R. Clark , Martin B. Plenio

We describe a novel end-to-end approach using Machine Learning to reconstruct the power spectrum of cosmological density perturbations at high redshift from observed quasar spectra. State-of-the-art cosmological simulations of structure…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-21 Maria Han Veiga , Xi Meng , Oleg Y. Gnedin , Nickolay Y. Gnedin , Xun Huan

Compressed sensing (CS) theory assures us that we can accurately reconstruct magnetic resonance images using fewer k-space measurements than the Nyquist sampling rate requires. In traditional CS-MRI inversion methods, the fact that the…

Computer Vision and Pattern Recognition · Computer Science 2018-03-28 Liyan Sun , Zhiwen Fan , Xinghao Ding , Congbo Cai , Yue Huang , John Paisley

The number of measurements required to reconstruct the states of quantum systems increases exponentially with the quantum system dimensions, which makes the state reconstruction of high-qubit quantum systems have a great challenge in…

Quantum Physics · Physics 2017-11-08 J. Yang , S. Cong , X. Liu , Z. Li , K. Li

In this work, we report on a novel quantum state reconstruction process based on the disentanglement algorithm. Using variational quantum circuits, we disentangle the quantum state to a product of computational zero states. Inverse…

Quantum Physics · Physics 2024-11-08 Juan Yao

A kind of least action principle is introduced for the discrete time evolution of one-dimensional quantum lattice models. Based on this principle, we obtain an optimal condition for the matrix product states on succeeding time slices…

Statistical Mechanics · Physics 2007-05-23 Kouji Ueda , Chenglong Jin , Naokazu Shibata , Yasuhiro Hieida , Tomotoshi Nishino

We present a universal technique for quantum state estimation based on the maximum-likelihood method. This approach provides a positive definite estimate for the density matrix from a sequence of measurements performed on identically…

Quantum Physics · Physics 2009-10-31 K. Banaszek , G. M. D'Ariano , M. G. A. Paris , M. F. Sacchi

To investigate a system coupled to a harmonic oscillator bath, we propose a new approach based on a phonon number representation of the bath. Compared to the method of the hierarchical equations of motion, the new approach is…

Quantum Physics · Physics 2020-01-08 M. Tokieda , K. Hagino

Combining redshift and galaxy shape information offers new exciting ways of exploiting the gravitational lensing effect for studying the large scales of the cosmos. One application is the three-dimensional reconstruction of the matter…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Patrick Simon , Andy Taylor , Jan Hartlap