Constraints on Lorentz violation from clock-comparison experiments

We consider Lorentz violation in supersymmetric extensions of the standard model. We perform a spurion analysis to show that, in the simplest natural constructions, the resulting supersymmetry-breaking masses are tiny. In the process, we argue that one of the strongest bounds on Lorentz violation in the photon Lagrangian, which comes from the absence of birefringence from distant astrophysical sources, does not apply when Lorentz violation is parametrized by a single vector.

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“…The clock comparison experiment [10] gives |c JK | ≤ 10 −27 for the neutron. A similar bound should hold for c JK at the quark level.…”

Section: Kähler Potential: the Minimal Modelmentioning

confidence: 99%

Lorentz violation and superpartner masses

Katz

Shadmi

2006

Phys. Rev. D

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“…, where Λ α µ is the standard Lorentz boost plus rotation from the SCCEF to the lab frame [7,10,18]. Thanks to the Earth's orbital velocity, the boost Λ α µ mixes the time and spatial components of c SCCEF αβ into the spatial components of c lab µν .…”

Section: Theorymentioning

confidence: 99%

“…In the SME, spin-independent violations of LLI for electrons generate a linearized perturbation of the electron c µν tensor to the Dirac Hamiltonian which may be written in natural units as [4,5,10,11] …”

Section: Theorymentioning

confidence: 99%

“…For a terrestrial laboratory, the lab-frame values of the tensor's dominant spatial components c lab jk depend upon the orientation of the lab with respect to the SCCEF, and thus modulate with characteristic frequency Ω ≃ 2 × 2π/(23 h 56 min), or twice every sidereal day. The value of the anomalous tensor in the lab-frame can be related to that in the SC-, where Λ α µ is the standard Lorentz boost plus rotation from the SCCEF to the lab frame [7,10,18]. Thanks to the Earth's orbital velocity, the boost Λ α µ mixes the time and spatial components of c SCCEF αβ into the spatial components of c lab µν .…”

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confidence: 99%

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Effects of Lorentz-symmetry violation on the spectra of rare-earth ions in a crystal field

Harabati¹,

Dzuba²,

Flambaum³

et al. 2015

Phys. Rev. A

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We demonstrate that experiments measuring the transition energies of rare-earth ions doped in crystalline lattices are sensitive to violations of Local Lorentz Invariance and Einstein's Equivalence Principle. Using the crystal field of LaCl3 as an example, we calculate the frame-dependent energy shifts of the transition frequencies between low-lying states of Ce 3+ , Nd 3+ , and Er 3+ dopants in the context of the Standard Model Extension, and show that they have high sensitivity to electron anomalies that break rotational invariance.PACS numbers: 03.30.+p, 11.30.Er, 11.30.Cp, 32.30.Jc Most of our day-to-day experiences are mediated by light and charged particles, and in particular its interaction with electrons. To the best of our knowledge, the physics of a system of photons and electrons is independent of the velocity and orientation of that system in absolute space, nor is it locally dependent upon where that system lies in a gravitational potential. These symmetries, respectively described as local Lorentz invariance (LLI) and Einstein's equivalence principle (EEP), are fundamental to our modern understanding of the standard model and general relativity. It is possible, however, that these symmetries are not exact at experimentally accessible energy scales, thanks to spontaneous symmetry breaking or other physics at high energy scales [1,2]. This possibility has driven many experimental tests of LLI and EEP [3], and motivated the development of phenomenological frameworks that can quantitatively describe the effect of LLI-and EEP-violation on known particles and fields. One such framework is provided by the standard model extension (SME) [4,5], which has been used to analyze a wide range of experiments [6]. The SME augments the standard model Lagrangian with all combinations of known particles and fields that are not invariant under Lorentz transformations, but which preserve gauge invariance, energy and translational invariance, and the invariance of the total action [4,5]. These terms are parameterized by Lorentz tensors that are collectively known as LLI-and EEP-violating coefficients, and are further subdivided into 'sectors' that deal with terms involving a particular particle. In this Letter, we focus on tests of the electron-sector c µν tensor, which modifies the inertial energy of electrons according to their direction of motion.Spectroscopy of neutral dysprosium atoms has already led to one of the world's most sensitive tests of electronic LLI and EEP [7]. More recently, a still more sensitive measurement of the electron c µν coefficients was obtained by engineering the quantum state of a pair of trapped Ca + ions [8], extending precision tests of electronic LLI past the electroweak (relative to the Planck mass) scale. Both of these experiments operate at or near the interrogation-time-of-flight or atom (ion) shot-noise limit. In this Letter, we consider the possibility of using rare earth ions doped in a crystalline lattice to perform similar measurements of the electronic c µν . Rare-earth ion...

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“…The SME is a dynamical model constructed to contain all Lorentz-and CPT-violating lagrangian terms consistent with coordinate independence, which is a fundamental requirement to be discussed below. To date, numerous Lorentz-and CPT-violation tests involving hadrons [8][9][10][11][12][13][14][15][16][17][18][19][20][21], protons and neutrons [22][23][24][25][26][27][28][29][30][31], electrons [31][32][33][34][35][36][37][38][39][40][41], photons [42][43][44][45][46][47], muons [48][49][50], and neutrinos [2,[51][52][53][54] have been analysed or identified within th...…”

Section: Motivationmentioning

confidence: 99%

The Lorentz-Violating Extension of the Standard Model

Lehnert

2004

Beyond the Desert 2003

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Abstract. Quantum-gravity effects are expected to be suppressed by the Planck mass. For experimental progress it is therefore important to identify potential signatures from Planck-scale physics that are amenable to ultrahigh-precision tests. It is argued that minuscule violations of Lorentz and CPT symmetry are candidate signals. In addition, theoretical and experimental aspects of the Standard-Model Extension, which describes the emergent low-energy effects, are discussed. MotivationAn important open question in our understanding of nature at its fundamental level concerns a unified quantum description of all fundamental interactions including gravity. Such a theory is likely to become dominant only as the Planck scale is approached, so that quantum-gravity effects are expected to be minuscule at presently attainable energies. Moreover, the absence of a fully realistic and viable candidate underlying theory provides a major obstacle for the identification of concrete quantum-gravity signatures that can be searched for in present-day or near-future experiments.A possible approach to overcome this phenomenological issue is to determine exact relations in the currently accepted laws of physics that may be violated in prospective fundamental theories and that can be tested with ultrahighprecision. Symmetries typically satisfy these criteria. For example, Lorentz and CPT invariance are cornerstones of our present understanding of nature at the fundamental level, and a variety of Lorentz and CPT tests belong to the most sensitive null experiments available. Lorentz and CPT violation is also a key feature of certain approaches to underlying physics.For example, couplings varying on cosmological scales are one possible source of Lorentz and CPT violation [1]. This fact does not come as a surprise: parameters dependent on spacetime break translational invariance, and translations, rotations, and boosts are linked in the Poincaré group. Thus, violations of translation symmetry can also affect Lorentz invariance. This can be understood intuitively as follows. The equations of motion typically contain the gradient of the coupling, which selects a preferred direction in spacetime leading to apparent Lorentz violation.In this talk, we discuss some theoretical and experimental aspects of the Standard-Model Extension (SME) [2][3][4][5][6][7], which is the low-energy framework for Lorentz-breaking effects. The SME is a dynamical model constructed to contain all Lorentz-and CPT-violating lagrangian terms consistent with coordinate

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Constraints on Lorentz violation from clock-comparison experiments

Cited by 404 publications

References 50 publications

Lorentz violation and superpartner masses

Lorentz violation and superpartner masses

Effects of Lorentz-symmetry violation on the spectra of rare-earth ions in a crystal field

The Lorentz-Violating Extension of the Standard Model

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