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We report the observation of entanglement between a single trapped atom and a single photon at remote locations. The degree of coherence of the entangled atom-photon pair is verified via appropriate local correlation measurements, after…

Quantum Physics · Physics 2009-11-13 W. Rosenfeld , F. Hocke , F. Henkel , M. Krug , J. Volz , M. Weber , H. Weinfurter

We characterize metrologically useful multipartite entanglement by representing partitions with Young diagrams. We derive entanglement witnesses that are sensitive to the shape of Young diagrams and show that Dyson's rank acts as a resource…

Quantum Physics · Physics 2021-02-26 Zhihong Ren , Weidong Li , Augusto Smerzi , Manuel Gessner

We propose a scheme based on using the singlet ground state of an electron spin pair in a double quantum dot nanostructure as a suitable set-up for detecting entanglement between electron spins via the measurement of an optimal entanglement…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 M. Blaauboer , D. P. DiVincenzo

Quantum entanglement has been identified as a crucial concept underlying many intriguing phenomena in condensed matter systems, such as topological phases or many-body localization. Recently, instead of considering mere quantifiers of…

Quantum Physics · Physics 2024-02-12 Niklas Euler , Martin Gärttner

Nuclear entanglement is a flagship in the interdisciplinary direction of nuclear physics and quantum information science. Spin entanglement, a special kind of nuclear entanglement, is ubiquitous in nuclear structures and dynamics. Based on…

Nuclear Theory · Physics 2024-03-08 Dong Bai

Historically, the completeness of quantum theory has been questioned using the concept of bipartite continuous variable entanglement. The non-classical correlations (entanglement) between the two subsystems imply that the observables of one…

Quantum Gases · Physics 2011-12-21 C. Gross , H. Strobel , E. Nicklas , T. Zibold , N. Bar-Gill , G. Kurizki , M. K. Oberthaler

Entangled many body systems have recently attracted significant attention in various contexts. Among them, spin squeezed atoms and ions have raised interest in the field of precision measurements, as they allow to overcome quantum noise of…

Quantum Physics · Physics 2008-10-28 T. Fernholz , H. Krauter , K. Jensen , J. F. Sherson , A. S. Soerensen , E. S. Polzik

We demonstrate spin gradient thermometry, a new general method of measuring the temperature of ultracold atoms in optical lattices. We realize a mixture of spins separated by a magnetic field gradient. Measurement of the width of the…

We study gradient magnetometry with an ensemble of atoms with arbitrary spin. We calculate precision bounds for estimating the gradient of the magnetic field based on the quantum Fisher information. For quantum states that are invariant…

Quantum Physics · Physics 2018-06-08 Iagoba Apellaniz , Inigo Urizar-Lanz , Zoltan Zimboras , Philipp Hyllus , Geza Toth

We show how one can entangle distant atoms by using squeezed light. Entanglement is obtained in steady state, and can be increased by manipulating the atoms locally. We study the effects of imperfections, and show how to scale up the scheme…

Quantum Physics · Physics 2009-11-10 Barbara Kraus , J. Ignacio Cirac

Optically-levitated dielectric objects are promising for precision force, acceleration, torque, and rotation sensing due to their extreme environmental decoupling. While many levitated opto-mechanics experiments employ spherical objects,…

We determine the complete set of generalized spin squeezing inequalities, given in terms of the collective angular momentum components, for particles with an arbitrary spin. They can be used for the experimental detection of entanglement in…

Quantum Physics · Physics 2015-01-27 Giuseppe Vitagliano , Philipp Hyllus , Inigo L. Egusquiza , Geza Toth

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…

The minimum requirements for entanglement detection are discussed for a spin chain in which the spins cannot be individually accessed. The methods presented detect entangled states close to a cluster state and a many-body singlet state, and…

Quantum Physics · Physics 2007-05-23 Geza Toth

We demonstrate spectroscopy and thermometry of individual motional modes in a mesoscopic 2D ion array using entanglement-induced decoherence as a method of transduction. Our system is a $\sim$400 $\mu$m-diameter planar crystal of several…

Characterizing entanglement in quantum materials is crucial for advancing next-generation quantum technologies. Despite recent strides in witnessing entanglement in magnetic materials with distinguishable spin modes, quantifying…

Strongly Correlated Electrons · Physics 2025-03-27 Tongtong Liu , Luogen Xu , Jiarui Liu , Yao Wang

In recent years inelastic spin-flip spectroscopy using a lowtemperature scanning tunneling microscope has been a very successful tool for studying not only individual spins but also complex coupled systems. When these systems interact with…

Mesoscale and Nanoscale Physics · Physics 2015-10-21 Markus Ternes

We derive conditions in the form of inequalities to detect the genuine $N$-partite entanglement of $N$ systems. The inequalities are expressed in terms of variances of spin operators, and can be tested by local spin measurements performed…

Quantum Physics · Physics 2020-09-24 R. Y. Teh , M. D. Reid

What is the relation between spin squeezing and entanglement? To clarify this, we derive the full set of generalized spin squeezing inequalities for the detection of entanglement. These are inequalities for the mean values and variances of…

Quantum Physics · Physics 2009-05-08 Geza Toth , Christian Knapp , Otfried Gühne , Hans J. Briegel

We propose three criteria for identifying continuous variable entanglement between two many-particle systems with no restrictions on the quantum state of the local oscillators used in the measurements. Mistakenly asserting a coherent state…

Quantum Physics · Physics 2009-11-13 A. J. Ferris , M. K. Olsen , E. G. Cavalcanti , M. J. Davis