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The ability to create and harness entanglement is crucial to the fields of quantum sensing and simulation, and ultracold atom-cavity systems offer pristine platforms for this undertaking. Here, we present a method for creating and…

In this paper, we investigate how to reduce the number of measurement configurations needed for sufficiently precise entanglement quantification. Instead of analytical formulae, we employ artificial neural networks to predict the amount of…

Quantum Physics · Physics 2022-07-20 Jan Roik , Karol Bartkiewicz , Antonín Černoch , Karel Lemr

Quantum technologies exploit entanglement to enhance various tasks beyond their classical limits including computation, communication and measurements. Quantum metrology aims to increase the precision of a measured quantity that is…

Quantum Physics · Physics 2020-08-25 Bálint Koczor , Suguru Endo , Tyson Jones , Yuichiro Matsuzaki , Simon C. Benjamin

This paper explores an efficient method for entanglement quantification in two-qubit and qubit-qutrit quantum systems based upon the framework of collective measurements in conjunction with machine learning. We introduce an adaptive…

Quantum Physics · Physics 2026-03-27 Martin Zeman , Vojtěch Trávníček , Antonín Černoch , Jan Soubusta , Karel Lemr

We show that the effect of measurement back-action results in the generation of multiple many-body spatial modes of ultracold atoms trapped in an optical lattice, when scattered light is detected. The multipartite mode entanglement…

Quantum metrology employs entanglement to enhance measurement precision. The focus and progress so far have primarily centered on estimating a single parameter. In diverse application scenarios, the estimation of more than one single…

Quantum Physics · Physics 2025-07-31 Jiahao Cao , Xinwei Li , Tianwei Mao , Wenxin Xu , Li You

We introduce a super-sensitive phase measurement technique that yields the Heisenberg limit without using either a squeezed state or a many-particle entangled state. Instead, we use a many-particle separable quantum state to probe the phase…

Quantum Physics · Physics 2020-05-20 Mayukh Lahiri , Manuel Erhard

Adaptive quantum circuits-where a quantum many-body state is controlled using measurements and conditional unitary operations-are a powerful paradigm for state preparation and quantum error correction tasks. They can support two types of…

Quantum Physics · Physics 2025-06-30 Thomas Iadecola , Justin H. Wilson , J. H. Pixley

Generic many-body systems coupled to an environment lose their quantum entanglement due to decoherence and evolve to a mixed state with only classical correlations. Here, we show that measurements can stabilize quantum entanglement within…

Quantum Physics · Physics 2022-09-07 Zack Weinstein , Yimu Bao , Ehud Altman

This paper presents simulations of the state vector dynamics for a pair of atomic samples which are being probed by phase shift measurements on an optical beam passing through both samples. We show how measurements, which are sensitive to…

Quantum Physics · Physics 2016-09-08 Antonio Di Lisi , Klaus Moelmer

Quantum non-demolition (QND) measurement of collective variables by off-resonant optical probing has the ability to create entanglement and squeezing in atomic ensembles. Until now, this technique has been applied to real or effective spin…

Quantum Physics · Physics 2015-05-19 M. Koschorreck , M. Napolitano , B. Dubost , M. W. Mitchell

We identify a phase transition between two kinds of volume-law entangled phases in non-local but few-body unitary dynamics with local projective measurements. In one phase, a finite fraction of the system belongs to a fully-entangled state,…

Quantum Physics · Physics 2020-05-08 Sagar Vijay

We show that combining randomized measurement protocols with importance sampling allows for characterizing entanglement in significantly larger quantum systems and in a more efficient way than in previous work. A drastic reduction of…

Quantum Physics · Physics 2023-01-26 Aniket Rath , Rick van Bijnen , Andreas Elben , Peter Zoller , Benoît Vermersch

We propose a method, based on matrix product states, for studying the time evolution of many-body quantum lattice systems under continuous and site-resolved measurement. Both the frequency and the strength of generalized measurements can be…

In quantum metrology, entangled states of many-particle systems are investigated to enhance measurement precision of the most precise clocks and field sensors. While single-parameter quantum metrology is well established, many metrological…

The entanglement of multi-atom quantum states is considered. In order to cancel noise due to inhomogeneous light atom coupling, the concept of matched multi-atom observables is proposed. As a means to eliminate an important form of…

Quantum Physics · Physics 2009-11-10 A. Kuzmich , T. A. B. Kennedy

When standard light sources are employed, the precision of the phase determination is limited by the shot noise. Quantum entanglement provides means to exceed this limit with the celebrated example of N00N states that saturate the ultimate…

Quantum Physics · Physics 2010-06-01 M. Kacprowicz , R. Demkowicz-Dobrzanski , W. Wasilewski , K. Banaszek , I. A. Walmsley

We introduce a new measure called reduced entropy of sublattice to quantify entanglement in spin, electron and boson systems. By analyzing this quantity, we reveal an intriguing connection between quantum entanglement and quantum phase…

Quantum Physics · Physics 2009-11-11 Y. Chen , Z. D. Wang , F. C. Zhang

The control over quantum states in atomic systems has led to the most precise optical atomic clocks to date. Their sensitivity is currently bounded by the standard quantum limit, a fundamental floor set by quantum mechanics for uncorrelated…

A weak measurement approach is proposed to entangle and squeeze atoms. We show that even for very small coupling strength between light and atoms, one can achieve large squeezing unattainable with normal measurement-based squeezing.…

Quantum Physics · Physics 2019-01-01 Mingfeng Wang , Weizhi Qu , Han Bao , Pengxiong Li , Yanhong Xiao