Unified Description of Nambu-Goldstone Bosons without Lorentz Invariance

Recent experimental developments in diverse areas -ranging from cold atomic gases to light-driven semiconductors to microcavity arrays -move systems into the focus which are located on the interface of quantum optics, many-body physics and statistical mechanics. They share in common that coherent and driven-dissipative quantum dynamics occur on an equal footing, creating genuine non-equilibrium scenarios without immediate counterpart in equilibrium condensed matter physics. This concerns both their non-thermal stationary states, as well as their many-body time evolution. It is a challenge to theory to identify novel instances of universal emergent macroscopic phenomena, which are tied unambiguously and in an observable way to the microscopic drive conditions. In this review, we discuss some recent results in this direction. Moreover, we provide a systematic introduction to the open system Keldysh functional integral approach, which is the proper technical tool to accomplish a merger of quantum optics and many-body physics, and leverages the power of modern quantum field theory to driven open quantum systems. CONTENTS

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“…The latter could be inferred along the lines of Refs. [220][221][222][223][224]. As we found in Sec.…”

Section: Spontaneous Symmetry Breaking and The Goldstone Theoremsupporting

confidence: 73%

Keldysh field theory for driven open quantum systems

2016

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“…[63], describes the realization of the SU(6) Hubbard model by loading an nuclear spin mixture of 173 Yb atoms in their ground state (g = 1 S 0 ) in a three-dimensional cubic optical lattice with lattice spacing a = 266 nm. The lattice was generated by d = 3 mutually orthogonal pairs of counter-propagating laser beams.…”

Section: Experiments In Optical Lattices: Realization Of a Su(6) mentioning

confidence: 99%

“…Experimental resolution of the nuclear spin sublevels: a) Spectroscopically interrogating the 1 S 0 -3 P 0 transition in an optical lattice clock [32] operated with 87 Sr gas, b) in a quantum degenerate gas of 173 Yb using Optical Stern-Gerlach (OSG) [63], c) Spectroscopically using the 1 S 0 -3 P 1 intercombination line in a cold quantum gas of 87 Sr atoms at a temperature of 0.5µK [86] and d) using Optical Stern-Gerlach (OSG) in a quantum degenerate 87 Sr gas [86].…”

Section: Imaging and Detection Of Nuclear Spin Componentsmentioning

confidence: 99%

Ultracold Fermi gases with emergent SU(N) symmetry

2014

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We review recent experimental and theoretical progress on ultracold alkaline-earth Fermi gases with emergent SU(N ) symmetry. Emphasis is placed on describing the ground-breaking experimental achievements of recent years. The latter include the cooling to below quantum degeneracy of various isotopes of ytterbium and strontium, the demonstration of optical Feshbach resonances and the optical Stern-Gerlach effect, the realization of a Mott insulator of 173 Yb atoms, the creation of various kinds of Fermi-Bose mixtures and the observation of many-body physics in optical lattice clocks. On the theory side, we survey the zoo of phases that have been predicted for both gases in a trap and loaded into an optical lattice, focusing on two and three-dimensional systems. We also discuss some of the challenges that lie ahead for the realization of such phases, such as reaching the temperature scale required to observe magnetic and more exotic quantum orders, and dealing with collisional relaxation of excited electronic levels.

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“…There is a vast literature on non-linear realizations of space-time symmetries in general and the inverse Higgs effect in particular. For various perspectives, see [603][604][605][606][607][608][609][610].…”

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confidence: 99%

Beyond the cosmological standard model

et al. 2015

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After a decade and a half of research motivated by the accelerating universe, theory and experiment have a reached a certain level of maturity. The development of theoretical models beyond Λ or smooth dark energy, often called modified gravity, has led to broader insights into a path forward, and a host of observational and experimental tests have been developed. In this review we present the current state of the field and describe a framework for anticipating developments in the next decade. We identify the guiding principles for rigorous and consistent modifications of the standard model, and discuss the prospects for empirical tests.We begin by reviewing recent attempts to consistently modify Einstein gravity in the infrared, focusing on the notion that additional degrees of freedom introduced by the modification must "screen" themselves from local tests of gravity. We categorize screening mechanisms into three broad classes: mechanisms which become active in regions of high Newtonian potential, those in which first derivatives of the field become important, and those for which second derivatives of the field are important. Examples of the first class, such as f (R) gravity, employ the familiar chameleon or symmetron mechanisms, whereas examples of the last class are galileon and massive gravity theories, employing the Vainshtein mechanism. In each case, we describe the theories as effective theories and discuss prospects for completion in a more fundamental theory. We describe experimental tests of each class of theories, summarizing laboratory and solar system tests and describing in some detail astrophysical and cosmological tests. Finally, we discuss prospects for future tests which will be sensitive to different signatures of new physics in the gravitational sector.The review is structured so that those parts that are more relevant to theorists vs. observers/experimentalists are clearly indicated, in the hope that this will serve as a useful reference for both audiences, as well as helping those interested in bridging the gap between them.

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Unified Description of Nambu-Goldstone Bosons without Lorentz Invariance

Cited by 245 publications

References 20 publications

Keldysh field theory for driven open quantum systems

Keldysh field theory for driven open quantum systems

Ultracold Fermi gases with emergent SU(N) symmetry

Beyond the cosmological standard model

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