Artigos de revistas: "Phenomenology of quantum gravity"

1

Amelino-Camelia, Giovanni. "Quantum-gravity phenomenology". Physics World 16, n.º 11 (novembro de 2003): 43–47. http://dx.doi.org/10.1088/2058-7058/16/11/37.

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Rovelli, Carlo. "Considerations on Quantum Gravity Phenomenology". Universe 7, n.º 11 (15 de novembro de 2021): 439. http://dx.doi.org/10.3390/universe7110439.

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SUDARSKY, DANIEL. "PERSPECTIVES ON QUANTUM GRAVITY PHENOMENOLOGY". International Journal of Modern Physics D 14, n.º 12 (dezembro de 2005): 2069–94. http://dx.doi.org/10.1142/s0218271805008145.

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The idea that quantum gravity manifestations are associated with a violation of Lorentz invariance is very strongly bounded and faces serious theoretical challenges. Other related ideas seem to be drowning in interpretational quagmires. This leads us to consider alternative lines of thought for such a phenomenological search. We discuss the underlying viewpoints and briefly mention their possible connections with other current theoretical ideas.

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AMELINO-CAMELIA, GIOVANNI. "QUANTUM-GRAVITY PHENOMENOLOGY: STATUS AND PROSPECTS". Modern Physics Letters A 17, n.º 15n17 (7 de junho de 2002): 899–922. http://dx.doi.org/10.1142/s0217732302007612.

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Over the last few years part of the quantum-gravity community has modified its attitude toward the possibility of finding experimental contexts that provide insight on non-classical properties of spacetime. I review those quantum-gravity phenomenology proposals which were instrumental in bringing about this change of attitude, and I discuss the prospects for the short-term future of quantum-gravity phenomenology.

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Liberati, S., e L. Maccione. "Quantum Gravity phenomenology: achievements and challenges". Journal of Physics: Conference Series 314 (22 de setembro de 2011): 012007. http://dx.doi.org/10.1088/1742-6596/314/1/012007.

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Sudarsky, Daniel. "A path towards quantum gravity phenomenology". Journal of Physics: Conference Series 66 (1 de maio de 2007): 012037. http://dx.doi.org/10.1088/1742-6596/66/1/012037.

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Bonder, Yuri. "An algorithm for quantum gravity phenomenology". Journal of Physics: Conference Series 1030 (maio de 2018): 012001. http://dx.doi.org/10.1088/1742-6596/1030/1/012001.

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Weinfurtner, Silke, Stefano Liberati e Matt Visser. "Analogue model for quantum gravity phenomenology". Journal of Physics A: Mathematical and General 39, n.º 21 (10 de maio de 2006): 6807–13. http://dx.doi.org/10.1088/0305-4470/39/21/s83.

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9

Olmo, Gonzalo J. "Palatini actions and quantum gravity phenomenology". Journal of Cosmology and Astroparticle Physics 2011, n.º 10 (13 de outubro de 2011): 018. http://dx.doi.org/10.1088/1475-7516/2011/10/018.

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Amelino-Camelia, Giovanni, Giacomo Rosati e Suzana Bedić. "Phenomenology of curvature-induced quantum-gravity effects". Physics Letters B 820 (setembro de 2021): 136595. http://dx.doi.org/10.1016/j.physletb.2021.136595.

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DOWKER, FAY, JOE HENSON e RAFAEL D. SORKIN. "QUANTUM GRAVITY PHENOMENOLOGY, LORENTZ INVARIANCE AND DISCRETENESS". Modern Physics Letters A 19, n.º 24 (10 de agosto de 2004): 1829–40. http://dx.doi.org/10.1142/s0217732304015026.

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Contrary to what is often stated, a fundamental spacetime discreteness need not contradict Lorentz invariance. A causal set's discreteness is in fact locally Lorentz invariant, and we recall the reasons why. For illustration, we introduce a phenomenological model of massive particles propagating in a Minkowski spacetime which arises from an underlying causal set. The particles undergo a Lorentz invariant diffusion in phase space, and we speculate on whether this could have any bearing on the origin of high energy cosmic rays.

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12

Bonder, Yuri, e Daniel Sudarsky. "Unambiguous quantum gravity phenomenology respecting lorentz symmetry". Reports on Mathematical Physics 64, n.º 1-2 (agosto de 2009): 169–84. http://dx.doi.org/10.1016/s0034-4877(09)90025-8.

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Dasgupta, Arundhati, e José Fajardo-Montenegro. "Aspects of Quantum Gravity Phenomenology and Astrophysics". Universe 9, n.º 3 (1 de março de 2023): 128. http://dx.doi.org/10.3390/universe9030128.

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With the discovery of gravitational waves, the search for the quantum of gravity, the graviton, is imminent. We discuss the current status of the bounds on graviton mass from experiments as well as the theoretical understanding of these particles. We provide an overview of current experiments in astrophysics such as the search for Hawking radiation in gamma-ray observations and neutrino detectors, which will also shed light on the existence of primordial black holes. Finally, the semiclassical corrections to the image of the event horizon are discussed.

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RINALDI, MASSIMILIANO. "ASPECTS OF QUANTUM GRAVITY IN COSMOLOGY". Modern Physics Letters A 27, n.º 07 (7 de março de 2012): 1230008. http://dx.doi.org/10.1142/s021773231230008x.

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We review some aspects of quantum gravity in the context of cosmology. In particular, we focus on models with a phenomenology accessible to current and near-future observations, as the early Universe might be our only chance to peep through the quantum gravity realm.

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Alonso-Serrano, Ana, e Marek Liška. "Quantum Gravity Phenomenology from the Thermodynamics of Spacetime". Universe 8, n.º 1 (13 de janeiro de 2022): 50. http://dx.doi.org/10.3390/universe8010050.

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This work is based on the formalism developed in the study of the thermodynamics of spacetime used to derive Einstein equations from the proportionality of entropy within an area. When low-energy quantum gravity effects are considered, an extra logarithmic term in the area is added to the entropy expression. Here, we present the derivation of the quantum modified gravitational dynamics from this modified entropy expression and discuss its main features. Furthermore, we outline the application of the modified dynamics to cosmology, suggesting the replacement of the Big Bang singularity with a regular bounce.

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CORICHI, ALEJANDRO, e DANIEL SUDARSKY. "TOWARDS A NEW APPROACH TO QUANTUM GRAVITY PHENOMENOLOGY". International Journal of Modern Physics D 14, n.º 10 (outubro de 2005): 1685–98. http://dx.doi.org/10.1142/s0218271805007541.

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The idea that quantum gravity manifestations would be associated with a violation of Lorentz invariance is very strongly bounded and faces serious theoretical challenges. This leads us to consider an alternative line of thought for such phenomenological search. We discuss the underlying viewpoint and briefly mention its possible connections with current theoretical ideas. We also outline the challenges that the experimental search of the effects would seem to face.

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17

Aloisio, R., P. Blasi, A. Galante, P. L. Ghia e A. F. Grillo. "Quantum-Gravity phenomenology and high energy particle propagation". Nuclear Physics B - Proceedings Supplements 136 (novembro de 2004): 344–49. http://dx.doi.org/10.1016/j.nuclphysbps.2004.10.014.

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18

Addazi, Andrea, e Rita Bernabei. "Non-commutative quantum gravity phenomenology in underground experiments". Modern Physics Letters A 34, n.º 29 (21 de setembro de 2019): 1950236. http://dx.doi.org/10.1142/s0217732319502365.

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We show how non-commutative spacetime models can induce Pauli Exclusion Principle (PEP) forbidden nuclear and atomic transitions. We focalize our analysis on one of the most popular instantiations of non-commutativeness: [Formula: see text]-Poincaré model, based on the Groenewold–Moyal plane algebra. We show that PEP violating transitions induced by [Formula: see text]-Poincaré have an energy scale and angular emission dependence. PEP violating transitions in nuclear and atomic systems can be tested with very high accuracy in underground laboratory experiments such as DAMA/LIBRA and VIP(2). We derive that the Equivalence Principle assumed [Formula: see text]-Poincaré model can be already ruled-out until the Planck scale, from nuclear transitions tests by DAMA/LIBRA experiment.

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BATTISTI, MARCO VALERIO, e GIOVANNI MONTANI. "COSMOLOGICAL IMPLICATIONS OF AN EVOLUTIONARY QUANTUM GRAVITY". International Journal of Modern Physics A 23, n.º 08 (30 de março de 2008): 1235–39. http://dx.doi.org/10.1142/s0217751x08040135.

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The cosmological implications of an evolutionary quantum gravity are analyzed in the context of a generic inhomogeneous model. The Schrödinger problem is formulated and solved in the presence of a scalar field, an ultrarelativistic matter and a perfect gas regarded as the dust-clock. Considering the actual phenomenology, it is shown how the evolutionary approach overlaps the Wheeler-DeWitt one.

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Brahma, Suddhasattwa, e Michele Ronco. "Constraining the loop quantum gravity parameter space from phenomenology". Physics Letters B 778 (março de 2018): 184–89. http://dx.doi.org/10.1016/j.physletb.2018.01.023.

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21

Bonder, Yuri, e Daniel Sudarsky. "Quantum gravity phenomenology without Lorentz invariance violation: a detailed proposal". Classical and Quantum Gravity 25, n.º 10 (7 de maio de 2008): 105017. http://dx.doi.org/10.1088/0264-9381/25/10/105017.

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22

Vacaru, Sergiu I. "Finsler branes and quantum gravity phenomenology with Lorentz symmetry violations". Classical and Quantum Gravity 28, n.º 21 (20 de setembro de 2011): 215001. http://dx.doi.org/10.1088/0264-9381/28/21/215001.

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23

CALMET, XAVIER. "A REVIEW OF QUANTUM GRAVITY AT THE LARGE HADRON COLLIDER". Modern Physics Letters A 25, n.º 19 (21 de junho de 2010): 1553–79. http://dx.doi.org/10.1142/s0217732310033591.

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The aim of this paper is to review the recent developments in the phenomenology of quantum gravity at the Large Hadron Collider. We shall pay special attention to four-dimensional models which are able to lower the reduced Planck mass to the TeV region and compare them to models with a large extra-dimensional volume. We then turn our attention to reviewing the emission of gravitons (massless or massive) at the LHC and to the production of small quantum black holes.

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24

Petruzziello, Luciano. "Casimir Effect as a Probe for New Physics Phenomenology". Physical Sciences Forum 2, n.º 1 (22 de fevereiro de 2021): 17. http://dx.doi.org/10.3390/ecu2021-09307.

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We show some recent cutting-edge results associated with the Casimir effect. Specifically, we focused our attention on the remarkable sensitivity of the Casimir effect to new physics phenomenology. Such an awareness can be readily discerned by virtue of the existence of extra contributions that the measurable quantities (such as the emergent pressure and strength within the experimental apparatus) acquire for a given physical setting. In particular, by relying on the above framework, we outlined the possibility of detecting the predictions of a novel quantum field theoretical description for particle mixing according to which the flavor and the mass vacuum are unitarily non-equivalent. Furthermore, by extending the very same formalism to curved backgrounds, the opportunity to probe extended models of gravity that encompass local Lorentz symmetry breaking and the strong equivalence principle violation was also discussed. Finally, the influence of quantum gravity on the Casimir effect was briefly tackled by means of heuristic considerations. In a similar scenario, the presence of a minimal length at the Planck scale was the source of the discrepancy with the standard outcomes.

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25

Amelino-Camelia, G., D. Frattulillo, G. Gubitosi, G. Rosati e S. Bedić. "Phenomenology of DSR-relativistic in-vacuo dispersion in FLRW spacetime". Journal of Cosmology and Astroparticle Physics 2024, n.º 01 (1 de janeiro de 2024): 070. http://dx.doi.org/10.1088/1475-7516/2024/01/070.

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Abstract Studies of in-vacuo dispersion are the most active area of quantum-gravity phenomenology. The way in which in-vacuo dispersion produces redshift-dependent corrections to the time of flight of astrophysics particles depends on the model-dependent interplay between Planck-scale effects and spacetime curvature/expansion, and we here derive the most general formula for the leading order redshift-dependent correction to the time of flight for the scenario in which relativistic symmetries are deformed at the Planck scale (DSR) for the constant-curvature case. We find that, contrary to the broken symmetries scenario (LIV), where in principle any arbitrary form of redshift dependence could be allowed, for the DSR scenario only linear combinations of three possible forms of redshift dependence are allowed. We also derive a generalization of our results to the FRW case, and discuss some specific combinations of the three forms of redshift dependence whose investigation might deserve priority from the quantum-gravity perspective.

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26

Hossenfelder, Sabine. "Theory and Phenomenology of Space-Time Defects". Advances in High Energy Physics 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/950672.

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Whether or not space-time is fundamentally discrete is of central importance for the development of the theory of quantum gravity. If the fundamental description of spacetime is discrete, typically represented in terms of a graph or network, then the apparent smoothness of geometry on large scales should be imperfect—it should have defects. Here, we review a model for space-time defects and summarize the constraints on the prevalence of these defects that can be derived from observation.

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AHLUWALIA, D. V. "INTERFACE OF GRAVITATIONAL AND QUANTUM REALMS". Modern Physics Letters A 17, n.º 15n17 (7 de junho de 2002): 1135–45. http://dx.doi.org/10.1142/s021773230200765x.

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The talk centers around the question: Can general-relativistic description of physical reality be considered complete? On the way I argue how – unknown to many a physicists, even today – the "forty orders of magnitude argument" against quantum gravity phenomenology was defeated more than a quarter of a century ago, and how we now stand at the possible verge of detecting a signal for the spacetime foam, and studying the gravitationally-modified wave particle duality using superconducting quantum interference devices.

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28

Blas, Diego, e Eugene Lim. "Phenomenology of theories of gravity without Lorentz invariance: The preferred frame case". International Journal of Modern Physics D 23, n.º 13 (novembro de 2014): 1443009. http://dx.doi.org/10.1142/s0218271814430093.

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Theories of gravitation without Lorentz invariance are candidates of low-energy descriptions of quantum gravity. In this paper, we will describe the phenomenological consequences of the candidates associated to the existence of a preferred time direction.

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Barrau, Aurélien, Boris Bolliet, Francesca Vidotto e Celine Weimer. "Phenomenology of bouncing black holes in quantum gravity: a closer look". Journal of Cosmology and Astroparticle Physics 2016, n.º 02 (9 de fevereiro de 2016): 022. http://dx.doi.org/10.1088/1475-7516/2016/02/022.

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30

Liberati, Stefano, Matt Visser e Silke Weinfurtner. "Analogue quantum gravity phenomenology from a two-component Bose–Einstein condensate". Classical and Quantum Gravity 23, n.º 9 (5 de abril de 2006): 3129–54. http://dx.doi.org/10.1088/0264-9381/23/9/023.

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AMELINO-CAMELIA, GIOVANNI. "PLANCK-LENGTH PHENOMENOLOGY". International Journal of Modern Physics D 10, n.º 01 (fevereiro de 2001): 1–7. http://dx.doi.org/10.1142/s0218271801001128.

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This author's recent proposal of interferometric tests of Planck-scale-related properties of spacetime is here revisited from a strictly phenomenological viewpoint. The results announced previously are rederived using elementary dimensional considerations. The dimensional analysis is then extended to the other two classes of experiments (observations of neutral kaons at particle accelerators and observations of the gamma rays we detect from distant astrophysical sources) which have been recently considered as opportunities to explore "foamy" properties of spacetime. The emerging picture suggests that there is an objective and intuitive way to connect the sensitivities of these three experiments with the Planck length. While in previous studies the emphasis was always on some quantum-gravity scenario and the analysis was always primarily aimed at showing that the chosen scenario would leave a trace in a certain class of doable experiments, the analysis here reported takes as starting point the experiments and, by relating in a direct quantitative way the sensitivities to the Planck length, provides a model-independent description of the status of Planck-length phenomenology.

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MOHRHOFF, ULRICH. "REFLECTIONS ON THE SPATIOTEMPORAL ASPECTS OF THE QUANTUM WORLD". Modern Physics Letters A 17, n.º 15n17 (7 de junho de 2002): 1107–21. http://dx.doi.org/10.1142/s0217732302007533.

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The proper resolution of the so-called measurement problem requires a "top-down" conception of the quantum world that is opposed to the usual "bottom-up" conception, which builds on an intrinsically and maximally differentiated manifold. The key to that problem is that the fuzziness of a variable can manifest itself only to the extent that less fuzzy variables exist. Inasmuch as there is nothing less fuzzy than the metric, this argues against a quantum-gravity phenomenology and suggests that a quantum theory of gravity is something of a contradiction in terms — a theory that would make it possible to investigate the physics on scales that do not exist, or to study the physical consequences of a fuzziness that has no physical consequences, other than providing a natural cutoff for the quantum field theories of particle physics.

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Liberati, Stefano, Giovanni Tricella e Andrea Trombettoni. "The Information Loss Problem: An Analogue Gravity Perspective". Entropy 21, n.º 10 (25 de setembro de 2019): 940. http://dx.doi.org/10.3390/e21100940.

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Analogue gravity can be used to reproduce the phenomenology of quantum field theory in curved spacetime and in particular phenomena such as cosmological particle creation and Hawking radiation. In black hole physics, taking into account the backreaction of such effects on the metric requires an extension to semiclassical gravity and leads to an apparent inconsistency in the theory: the black hole evaporation induces a breakdown of the unitary quantum evolution leading to the so-called information loss problem. Here, we show that analogue gravity can provide an interesting perspective on the resolution of this problem, albeit the backreaction in analogue systems is not described by semiclassical Einstein equations. In particular, by looking at the simpler problem of cosmological particle creation, we show, in the context of Bose–Einstein condensates analogue gravity, that the emerging analogue geometry and quasi-particles have correlations due to the quantum nature of the atomic degrees of freedom underlying the emergent spacetime. The quantum evolution is, of course, always unitary, but on the whole Hilbert space, which cannot be exactly factorized a posteriori in geometry and quasi-particle components. In analogy, in a black hole evaporation one should expect a continuous process creating correlations between the Hawking quanta and the microscopic quantum degrees of freedom of spacetime, implying that only a full quantum gravity treatment would be able to resolve the information loss problem by proving the unitary evolution on the full Hilbert space.

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Bernardo, Heliudson, Benjamin Bose, Guilherme Franzmann, Steffen Hagstotz, Yutong He, Aliki Litsa e Florian Niedermann. "Modified Gravity Approaches to the Cosmological Constant Problem". Universe 9, n.º 2 (20 de janeiro de 2023): 63. http://dx.doi.org/10.3390/universe9020063.

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The cosmological constant and its phenomenology remain among the greatest puzzles in theoretical physics. We review how modifications of Einstein’s general relativity could alleviate the different problems associated with it that result from the interplay of classical gravity and quantum field theory. We introduce a modern and concise language to describe the problems associated with its phenomenology, and inspect no-go theorems and their loopholes to motivate the approaches discussed here. Constrained gravity approaches exploit minimal departures from general relativity; massive gravity introduces mass to the graviton; Horndeski theories lead to the breaking of translational invariance of the vacuum; and models with extra dimensions change the symmetries of the vacuum. We also review screening mechanisms that have to be present in some of these theories if they aim to recover the success of general relativity on small scales as well. Finally, we summarize the statuses of these models in their attempts to solve the different cosmological constant problems while being able to account for current astrophysical and cosmological observations.

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Ballesteros, Angel, Giulia Gubitosi e Flavio Mercati. "Interplay between Spacetime Curvature, Speed of Light and Quantum Deformations of Relativistic Symmetries". Symmetry 13, n.º 11 (5 de novembro de 2021): 2099. http://dx.doi.org/10.3390/sym13112099.

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Recent work showed that κ-deformations can describe the quantum deformation of several relativistic models that have been proposed in the context of quantum gravity phenomenology. Starting from the Poincaré algebra of special-relativistic symmetries, one can toggle the curvature parameter Λ, the Planck scale quantum deformation parameter κ and the speed of light parameter c to move to the well-studied κ-Poincaré algebra, the (quantum) (A)dS algebra, the (quantum) Galilei and Carroll algebras and their curved versions. In this review, we survey the properties and relations of these algebras of relativistic symmetries and their associated noncommutative spacetimes, emphasizing the nontrivial effects of interplay between curvature, quantum deformation and speed of light parameters.

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Addazi, Andrea, e Rita Bernabei. "Tests of Pauli exclusion principle violations from noncommutative quantum gravity". International Journal of Modern Physics A 35, n.º 32 (2 de novembro de 2020): 2042001. http://dx.doi.org/10.1142/s0217751x20420014.

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We review the main recent progresses in noncommutative space–time phenomenology in underground experiments. A popular model of noncommutative space–time is [Formula: see text]-Poincaré model, based on the Groenewold–Moyal plane algebra. This model predicts a violation of the spin-statistic theorem, in turn implying an energy and angular dependent violation of the Pauli exclusion principle. Pauli exclusion principle violating transitions in nuclear and atomic systems can be tested with very high accuracy in underground laboratory experiments such as DAMA/LIBRA and VIP(2). In this paper we derive that the [Formula: see text]-Poincaré model can be already ruled-out until the Planck scale, from nuclear transitions tests by DAMA/LIBRA experiment.

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Piórkowska-Kurpas, Aleksandra, e Marek Biesiada. "Testing Quantum Gravity in the Multi-Messenger Astronomy Era". Universe 8, n.º 6 (8 de junho de 2022): 321. http://dx.doi.org/10.3390/universe8060321.

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Quantum gravity (QG) remains elusive despite almost century-long efforts to combine general relativity and quantum mechanics. All the approaches triggered and powered by purely theoretical considerations eventually failed with a prevailing feeling of a complete lack of guidance from the experimental side. Currently, however, this circumstance is beginning to change considerably. We have entered the era of multi-messenger astronomy. The electromagnetic window to the universe—so far the only one—has been tremendously enlarged in the energy range beyond gamma rays up to ultra-high-energy photons and has been complemented by other messengers: high-energy cosmic rays, cosmic neutrinos, and gravitational waves (GWs). This has created a unique environment in which to observationally constrain various phenomenological QG effects. In this paper, we focus on the LIV phenomenology manifested as energy-dependent time-of-flight delays and strong lensing time delays. We review results regarding time-of-flight delays obtained with GRBs. We also recall the idea of energy-dependent lensing time delays, which allow one to constrain LIV models independently of the intrinsic time delay. Lastly, we show how strongly a gravitationally lensed GW signal would place interesting constraints on the LIV.

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ELLIS, JOHN, NICK E. MAVROMATOS, DIMITRI V. NANOPOULOS e ALEXANDER S. SAKHAROV. "SPACE–TIME FOAM MAY VIOLATE THE PRINCIPLE OF EQUIVALENCE". International Journal of Modern Physics A 19, n.º 26 (20 de outubro de 2004): 4413–30. http://dx.doi.org/10.1142/s0217751x04019780.

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The interactions of different particle species with the foamy space–time fluctuations expected in quantum gravity theories may not be universal, in which case different types of energetic particles may violate Lorentz invariance by varying amounts, violating the equivalence principle. We illustrate this possibility in two different models of space–time foam based on D-particle fluctuations in either flat Minkowski space or a stack of intersecting D-branes. Both models suggest that Lorentz invariance could be violated for energetic particles that do not carry conserved charges, such as photons, whereas charged particles such electrons would propagate in a Lorentz-inavariant way. The D-brane model further suggests that gluon propagation might violate Lorentz invariance, but not neutrinos. We argue that these conclusions hold at both the tree (lowest-genus) and loop (higher-genus) levels, and discuss their implications for the phenomenology of quantum gravity.

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Mavromatos, Nick E. "Models & Searches of CPT Violation: a personal, very partial, list". EPJ Web of Conferences 166 (2018): 00005. http://dx.doi.org/10.1051/epjconf/201816600005.

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In this talk, first I motivate theoretically, and then I review the phenomenology of, some models entailing CPT Violation (CPTV). The latter is argued to be responsible for the observed matter-antimatter asymmetry in the Cosmos, and may owe its origin to either Lorentz-violating background geometries, whose effects are strong in early epochs of the Universe but very weak today, being temperature dependent in general, or to an ill-defined CPT generator in some quantum gravity models entailing decoherence of quantum matter as a result of quantum degrees of freedom in the gravity sector that are inaccessible to the low-energy observers. In particular, for the latter category of CPTV, I argue that entangled states of neutral mesons (Kaons or B-systems), of central relevance to KLOE-2 experiment, can provide smoking-gun sensitive tests or even falsify some of these models. If CPT is ill-defined one may also encounter violations of the spin-statistics theorem, with possible consequences for the Pauli Exclusion Principle, which I only briefly touch upon.

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NG, Y. JACK. "SELECTED TOPICS IN PLANCK-SCALE PHYSICS". Modern Physics Letters A 18, n.º 16 (30 de maio de 2003): 1073–97. http://dx.doi.org/10.1142/s0217732303010934.

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We review a few topics in Planck-scale physics, with emphasis on possible manifestations in relatively low energy. The selected topics include quantum fluctuations of spacetime, their cumulative effects, uncertainties in energy–momentum measurements, and low energy quantum-gravity phenomenology. The focus is on quantum-gravity-induced uncertainties in some observable quantities. We consider four possible ways to probe Planck-scale physics experimentally: (i) looking for energy-dependent spreads in the arrival time of photons of the same energy from GRBs; (ii) examining spacetime fluctuation-induced phase incoherence of light from extragalactic sources; (iii) detecting spacetime foam with laser-based interferometry techniques; (iv) understanding the threshold anomalies in high energy cosmic ray and gamma ray events. Some other experiments are briefly discussed. We show how some physics behind black holes, simple clocks, simple computers, and the holographic principle is related to Planck-scale physics. We also discuss a formulation of the Dirac equation as a difference equation on a discrete Planck-scale spacetime lattice, and a possible interplay between Planck-scale and Hubble-scale physics encoded in the cosmological constant (dark energy).

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Kaloper, Nemanja. "Dark energy, H0 and weak gravity conjecture". International Journal of Modern Physics D 28, n.º 14 (outubro de 2019): 1944017. http://dx.doi.org/10.1142/s0218271819440176.

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We point out that the physics at the extreme IR — cosmology — might provide tests of the physics of the extreme UV — the Weak Gravity Conjecture. The current discrepancies in the determination of [Formula: see text] may hint at a modification of [Formula: see text]CDM. An extension which may fit better comprises an early contribution to dark energy which “decays” into relativistic matter. On the other hand, the discourse on WGC to date suggests that fields which support cosmic acceleration may produce relativistic matter after they traverse a [Formula: see text] Planckian distance in field space. We explain how this offers a simple realization of the requisite cosmic phenomenology. Thus, if the resolution of [Formula: see text] discrepancies is really early dark energy that ends with a shower of relativistic matter and the current ideas on WGC are indicative, this may be a rare opportunity to link the two extreme limits of quantum field theory.

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Carloni, Sante, Roberto Cianci, Olindo Corradini, Antonino Flachi, Stefano Vignolo e Vincenzo Vitagliano. "Avenues of Quantum Field Theory in Curved Spacetime, Genova, 14-16 Sep 2022". Journal of Physics: Conference Series 2531, n.º 1 (1 de junho de 2023): 011001. http://dx.doi.org/10.1088/1742-6596/2531/1/011001.

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The extreme conditions experienced in the early universe, close to a black hole or in the interior of a neutron star, provide the environment where the most violent natural phenomena take place. Our understanding of the physical processes occurring in these regimes is affected by the notorious difficulty in the development of a theory of quantum gravity, modelling the intertwining of the gravitational field and the quantum properties of the fields responsible for the other forces in nature. A different point of view is then achieved by defining a “mesoscopic” scale lying below the Planck energy scale but well away from the classical general relativity domain. At such a scale, the theoretical framework describing how quantized fields propagate in a curved background has accomplished outstanding results, like particle production in gravitational fields and black hole evaporation, establishing a highly non-trivial connection between thermodynamics, gravity, and quantum field theory. Aside from suggesting novel intersections between quantum fields and gravity, an unexplored landscape of original ideas is taking shape and inspiring new exciting problems. Quantum field theory in curved spacetime has recently been proposed as a new tool to probe nuclear and condensed matter physics phenomenology, with the recent advances in research at the nanoscale offering an intriguing test to the semiclassical approach even from tabletop experiments. Following this trend, the goal of Avenues of Quantum Field Theory in Curved Spacetime has been to bring together researchers working in different areas of quantum field theory with interest in its curved space applications in the area of gravity and beyond. The 3-days workshop - the third of a series initiated in 2018 in Japan, continued in Modena, and that had an unexpected stop due to the sadly well-known Covid19 facts - aimed to exchange ideas on what is (or is expected soon to become) topical and discuss potential interdisciplinary interactions in a stimulating and collaborative environment. List of The Editorial Board and Organising Committee is available in this pdf.

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Luciano, Giuseppe Gaetano. "Gravity and Cosmology in Kaniadakis Statistics: Current Status and Future Challenges". Entropy 24, n.º 12 (24 de novembro de 2022): 1712. http://dx.doi.org/10.3390/e24121712.

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Kaniadakis statistics is a widespread paradigm to describe complex systems in the relativistic realm. Recently, gravitational and cosmological scenarios based on Kaniadakis (κ-deformed) entropy have been considered, leading to generalized models that predict a richer phenomenology comparing to their standard Maxwell–Boltzmann counterparts. The purpose of the present effort is to explore recent advances and future challenges of Gravity and Cosmology in Kaniadakis statistics. More specifically, the first part of the work contains a review of κ-entropy implications on Holographic Dark Energy, Entropic Gravity, Black hole thermodynamics and Loop Quantum Gravity, among others. In the second part, we focus on the study of Big Bang Nucleosynthesis in Kaniadakis Cosmology. By demanding consistency between theoretical predictions of our model and observational measurements of freeze-out temperature fluctuations and primordial abundances of 4He and D, we constrain the free κ-parameter, discussing to what extent the Kaniadakis framework can provide a successful description of the observed Universe.

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Nasser Tawfik, Abdel, e Abdel Magied Diab. "Black hole corrections due to minimal length and modified dispersion relation". International Journal of Modern Physics A 30, n.º 12 (28 de abril de 2015): 1550059. http://dx.doi.org/10.1142/s0217751x15500591.

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The generalized uncertainty principles (GUP) and modified dispersion relations (MDR) are much like two faces for one coin in research for the phenomenology of quantum gravity which apparently plays an important role in estimating the possible modifications of the black hole thermodynamics and the Friedmann equations. We first reproduce the horizon area for different types of black holes and investigate the quantum corrections to Bekenstein–Hawking entropy (entropy-area law). Based on this, we study further thermodynamical quantities and accordingly the modified Friedmann equation in four-dimensional de Sitter–Schwarzschild, Reissner–Nördstrom and Garfinkle–Horowitz–Strominger black holes. In doing this, we applied various quantum gravity approaches. The MDR parameter relative to the GUP one is computed and the properties of the black holes are predicted. This should play an important role in estimating response of quantum gravity to the various metric-types of black holes. We found a considerable change in the thermodynamics quantities. We find that the modified entropy of de Sitter–Schwarzshild and Reissner–Nördstrom black holes starts to exist at a finite standard entropy. The Garfinkle–Horowitz–Strominger black hole shows a different entropic property. The modified specific heat due to GUP and MDR approaches vanishes at large standard specific heat, while the corrections due to GUP result in different behaviors. The specific heat of modified de Sitter–Schwarzshild and Reissner–Nördstrom black holes seems to increase, especially at large standard specific heat. In the early case, the black hole cannot exchange heat with the surrounding space. Accordingly, we would predict black hole remnants which may be considered as candidates for dark matter.

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Barrau, Aurélien, Killian Martineau e Flora Moulin. "A Status Report on the Phenomenology of Black Holes in Loop Quantum Gravity: Evaporation, Tunneling to White Holes, Dark Matter and Gravitational Waves". Universe 4, n.º 10 (2 de outubro de 2018): 102. http://dx.doi.org/10.3390/universe4100102.

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The understanding of black holes in loop quantum gravity is becoming increasingly accurate. This review focuses on the possible experimental or observational consequences of the underlying spinfoam structure of space-time. It addresses both the aspects associated with the Hawking evaporation and the ones due to the possible existence of a bounce. Finally, consequences for dark matter and gravitational waves are considered.

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Bianco, Stefano. "Phenomenology from the DSR-deformed relativistic symmetries of 3D quantum gravity via the relative-locality framework". Journal of Physics: Conference Series 634 (3 de agosto de 2015): 012003. http://dx.doi.org/10.1088/1742-6596/634/1/012003.

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Torri, Marco Danilo Claudio. "Quantum Gravity Phenomenology Induced in the Propagation of UHECR, a Kinematical Solution in Finsler and Generalized Finsler Spacetime". Galaxies 9, n.º 4 (14 de novembro de 2021): 103. http://dx.doi.org/10.3390/galaxies9040103.

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It is well-known that the universe is opaque to the propagation of Ultra-High-Energy Cosmic Rays (UHECRs) since these particles dissipate energy during their propagation interacting with the background fields present in the universe, mainly with the Cosmic Microwave Background (CMB) in the so-called GZK cut-off phenomenon. Some experimental evidence seems to hint at the possibility of a dilation of the GZK predicted opacity sphere. It is well-known that kinematical perturbations caused by supposed quantum gravity (QG) effects can modify the foreseen GZK opacity horizon. The introduction of Lorentz Invariance Violation can indeed reduce, and in some cases making negligible, the CMB-UHECRs interaction probability. In this work, we explore the effects induced by modified kinematics in the UHECR lightest component phenomenology from the QG perspective. We explore the possibility of a geometrical description of the massive fermions interaction with the supposed quantum structure of spacetime in order to introduce a Lorentz covariance modification. The kinematics are amended, modifying the dispersion relations of free particles in the context of a covariance-preserving framework. This spacetime description requires a more general geometry than the usual Riemannian one, indicating, for instance, the Finsler construction and the related generalized Finsler spacetime as ideal candidates. Finally we investigate the correlation between the magnitude of Lorentz covariance modification and the attenuation length of the photopion production process related to the GZK cut-off, demonstrating that the predicted opacity horizon can be dilated even in the context of a theory that does not require any privileged reference frame.

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Barceló, Carlos, Raúl Carballo-Rubio e Luis J. Garay. "Uncovering the effective spacetime: Lessons from the effective field theory rationale". International Journal of Modern Physics D 24, n.º 12 (outubro de 2015): 1544019. http://dx.doi.org/10.1142/s0218271815440198.

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The cosmological constant problem can be understood as the failure of the decoupling principle behind effective field theory, so that some quantities in the low-energy theory are extremely sensitive to the high-energy properties. While this reflects the genuine character of the cosmological constant, finding an adequate effective field theory framework which avoids this naturalness problem may represent a step forward to understand nature. Following this intuition, we consider a minimal modification of the structure of general relativity which as an effective theory permits to work consistently at low energies, i.e. below the quantum gravity scale. This effective description preserves the classical phenomenology of general relativity and the particle spectrum of the standard model, at the price of changing our conceptual and mathematical picture of spacetime.

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Pugliese, Daniela, e Giovanni Montani. "Constraining LQG Graph with Light Surfaces: Properties of BH Thermodynamics for Mini-Super-Space, Semi-Classical Polymeric BH". Entropy 22, n.º 4 (31 de março de 2020): 402. http://dx.doi.org/10.3390/e22040402.

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This work participates in the research for potential areas of observational evidence of quantum effects on geometry in a black hole astrophysical context. We consider properties of a family of loop quantum corrected regular black hole (BHs) solutions and their horizons, focusing on the geometry symmetries. We study here a recently developed model, where the geometry is determined by a metric quantum modification outside the horizon. This is a regular static spherical solution of mini-super-space BH metric with Loop Quantum Gravity (LQG) corrections. The solutions are characterized delineating certain polymeric functions on the basis of the properties of the horizons and the emergence of a singularity in the limiting case of the Schwarzschild geometry. We discuss particular metric solutions on the base of the parameters of the polymeric model related to similar properties of structures, the metric Killing bundles (or metric bundles MBs), related to the BH horizons’ properties. A comparison with the Reissner–Norström geometry and the Kerr geometry with which analogies exist from the point of their respective MBs properties is done. The analysis provides a way to recognize these geometries and detect their main distinctive phenomenological evidence of LQG origin on the basis of the detection of stationary/static observers and the properties of light-like orbits within the analysis of the (conformal invariant) MBs related to the (local) causal structure. This approach could be applied in other quantum corrected BH solutions, constraining the characteristics of the underlining LQG-graph, as the minimal loop area, through the analysis of the null-like orbits and photons detection. The study of light surfaces associated with a diversified and wide range of BH phenomenology and grounding MBs definition provides a channel to search for possible astrophysical evidence. The main BHs thermodynamic characteristics are studied as luminosity, surface gravity, and temperature. Ultimately, the application of this method to this spherically symmetric approximate solution provides us with a way to clarify some formal aspects of MBs, in the presence of static, spherical symmetric spacetimes.

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Albalate, Germán, José Carmona, José Cortés e José Relancio. "Twin Peaks: A Possible Signal in the Production of Resonances beyond Special Relativity". Symmetry 10, n.º 10 (25 de setembro de 2018): 432. http://dx.doi.org/10.3390/sym10100432.

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It is usually expected that quantum gravity corrections will modify somehow the symmetries of special relativity. In this paper, we point out that the possibility of very low-energy (with respect to the Planck energy) modifications to special relativity in the framework of a deformed relativistic theory is not ruled out, and that, depending on the value of that scale, such a possibility could be tested in accelerator physics. In particular, we take a simple example of a relativistic kinematics beyond special relativity from the literature, and obtain a remarkable effect: two correlated peaks (twin peaks) associated with a single resonance. We analyze this phenomenology in detail, use present experimental data to put constraints of the order of TeV on the scale of corrections to special relativity, and note that such an effect might be observable in a future very high-energy proton collider.

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