València VI Postgraduate Meeting On Theoretical Physics

picture of Oviedo


Title: Holographic non computers

Speaker: Javier Martín García (IFT UAM/CSIC)

Abstract: Along the lines of other work relating quantum information theory and gravity, quantum complexity has been conjectured to provide a dual description of the geometry of black hole interiors. In this context, we introduce the concept of a non-computer as a system which exhibits parametrically large delays in the growth of complexity, providing thus an example of exotic phenomenology that could be used to clarify the details of the very conjecture.

Title: Flux-induced soft supersymmetry breaking terms in Type IIA compactifications with D6-branes

Speaker: Dagoberto Escobar Atienzar (IFT UAM/CSIC)

Abstract: We consider Type IIA string theory compactifications on Calabi-Yau orientifolds with non-trivial background fluxes and D6-branes supporting chiral gauge theories. The background fluxes used for the stabilisation of the closed string moduli simultaneously provide the source for spontaneous supersymmetry breaking which induce soft terms for the fields living on the D6-brane worldvolumes. We derive the general expressions for these terms which can be applied to a large class of D6-brane constructions. As an explicit example of soft supersymmetry breaking terms we consider no-scale vacua and discuss their relation to the Higgs-axion sector of consistent DFSZ axion models.

Title: Observable traces of non-metricity: accelerator constraints on metric-affine gravity

Speaker: Adrià Delhom I Latorre

Abstract: Relaxing the Riemannian condition to incorporate geometric quantities such as torsion and non-metricity may allow to explore new physics associated with defects in a hypothetical space-time microstructure. Here we show that non-metricity produces observable effects in quantum fields in the form of 4-fermion contact interactions, thereby allowing us to constrain the scale of non-metricity to be greater than 1 TeV by using results on Bahbah scattering. Our analysis is carried out in the framework of a wide class of theories of gravity in the metric-affine approach. The bound obtained represents an improvement of several orders of magnitude to previous experimental constraints.

Title: Gravitational and thermal effects on massive scalar fields at one loop

Speaker: Franco D. Albareti (IFT UAM/CSIC)

Abstract: We study possible effects of classical gravitational backgrounds on the dynamics of a massive scalar field computing one-loop corrections induced by its self-interactions. Vaccum and finite temperature contributions to the energy-momentum tensor and the effective potential are described. Our approach is based on the explicit mode decomposition of the field in the preturbed geometry instead of the local approach based on the Schwinger-De Witt expansion. For vaccum contritributions, we discuss two different regularization procedures: a cutoff and dimensional regularization. On the other hand, thermal corrections show that global thermal effects in a curved spacetime can be encoded in the local Tolman temperature at leading order in perturbations and in the adiabatic expansion.

Title: All entangled states can demonstrate non-classical teleportation

Speaker: Ivan Supic (ICFO - The Institute of Photonic Sciences)

Abstract: Quantum teleportation, the process by which Alice can transfer an unknown quantum state to Bob by using pre-shared entanglement and classical communication, is one of the cornerstones of quantum information. The standard benchmark for certifying quantum teleportation consists in surpassing the maximum average fidelity between the teleported and the target states that can be achieved classically. According to this figure of merit, not all entangled states are useful for teleportation. Here we propose a new benchmark that uses the full information available in a teleportation experiment and prove that all entangled states can implement a quantum channel which can not be reproduced classically. We introduce the idea of non-classical teleportation witness to certify if a teleportation experiment is genuinely quantum and discuss how to quantify this phenomenon. Our work provides new techniques for studying teleportation that can be immediately applied to certify the quality of quantum technologies.

Title: Comprehensive Unification

Speaker: Mario Reig (IFIC UV/CSIC)

Abstract: Comprehensive - that is, gauge and family - unification using spinors has many attractive features, but it has been challenged to explain chirality. In this talk I will show that by combining an orbifold construction together with hypercolor confinement one can obtain an effective theory with only three chiral families. A potential target for accelerator and astronomical searches emerges.

Title: Dark matter in multimetric gravity

Speaker: Nicolas L. Gonzalez Albornoz (University of Munich)

Abstract: We consider a special case of ghost-free (N+1)-metric gravity with a certain maximal global discrete symmetry. By studying the eigenstates of the theory, we find a massless, a massive and N-1 identical less massive spin-2 modes. The lighter modes are stable i.e.: they do not decay into massless gravitons. We investigate two possible parameter regions of the theory where the lighter modes can be dark matter and where the theory passes all tests of general relativity.

Title: Domain wall problem in the Next-to-Minimal Supersymmetric The next-to-minimal supersymmetric standard model predicts the formation of domain walls due to the spontaneous breaking of the discrete Z3-symmetry at the electroweak phase transition, and they collapse before the epoch of big bang nucleosynthesis if there exists a small bias term in the potential which explicitly breaks the discrete symmetry. Signatures of gravitational waves produced from these unstable domain walls are estimated and their parameter dependence is investigated. Standard Model

Speaker: Ouahid Mohamed-Amine (University of Mohammed V Rabat)


Title: Epsilon prime in the Standard Model

Speaker: Hector Gisbert Mullor (IFIC UV/CSIC)

Abstract: No Abstract

Title: Extended non relativistic algebras

Speaker:Gustavo rubio (Universidad de Concepci&oaccute;n)

Abstract: It's proposed an extension of the gauge principle in non relativistic theorys, which includes gauge fields tensors. In this extension of the Yang Mills theory the bosonic gauge vector becomes a family of gauge fields of greater rank.

Title: First order quadratic gravity: A consistent UV completion?

Speaker: Raquel Santos (IFT UAM/CSIC)

Abstract: First, we present the computation of the one-loop counterterms of the Einstein Hilbert action in first order formalism (which is in agreement with the result by 't Hooft and Veltman in second order) and analize the effects of matter sources. In addition, a brief overview of the most general action for gravity which is quadratic in curvature is presented in first order formalism, and we argue why it is a good candidate for a unitary and renormalizable theory of the gravitational field. Work is in progress regarding the computation of the one loop counterterms for this theory.

Title: Flavour alignment in multi-Higgs models

Speaker: Ana Peñuelas Mart&iaccute;nez (IFIC UV/CSIC)

Abstract: Extended electroweak scalar sectors containing several doublet multiplets are good candidates for studying extensions of the Standard Model and require flavour-aligned Yukawa matrices to prevent the appearance at tree level of unwanted flavour-changing neutral-current transitions. We analize the misalignment induced by one-loop quantum corrections and explore their compatibility with known experimental constraints.

Title: Geometric flows and bounds for mass and entropy.

Speaker: Oscar Lasso (IFT UAM/CSIC)

Abstract: It is well known that geometric flows have been a key tool for getting very important results in many branches of pure mathematics. They also have been used in te context of mathematical physics, the riemannian Penrose inequality is a promiment example were the inverse mean curvature flow was employed. Those techniques are very powerfull and can be used for a better understanding of deep aspects of any geometric theory. I will show how to determine bounds for the area and the Hawking mass using the RG-2 flow. I will discuss the relationship between different flows and its applications. Finally I will talk about new approaches to open problems.

Title: Christoph Andreas Ternes (IFIC UV(CSIC)

Speaker: Sensitivity to CPT-violation at DUNE

Abstract: No Abstract

Title: Holographic RG flows and anomalous transport

Speaker: Jorge Fernández-Pendás (IFT UAM/CSIC)

Abstract: Axial and gravitational anomalies are responsible for the generation of disipationless transport phenomena due to magnetic field and vorticity. While still mysterious from a QFT point of view, this phenomena are better understood in holography. In this talk I will try to explain how the AdS/CFT correspondence allows us to extract the low energy physics of the theory and use conserved quantities in the gravity side to relate IR physics to the field theory 1-pt functions.

Title: Instantons, dimers and Bipartite Field Theories.

Speaker: Eduardo Garcia-Valdecasas Tenreiro (IFT UAM/CSIC)

Abstract: I will discuss recent results and applications regarding works arXiv:1605.08092 and arXiv:1704.05888. In particular, I will discuss how to introduce D-brane instantons on dimer models geometrically and how this can be used to obtain Bipartite Field Theories. I will also comment on some remarks regarding Seiberg Duality.

Title: Is Unimodular Gravity equivalent to General Relativity?

Speaker: Sergio Gonzalez-Martin (IFT UV/CSIC)

Abstract: Unimodular gravity is an alternative theory of gravity which is classically equivalent to general relativity but does not couple to the vacuum energy (hence partially solving the cosmological constant problem). Several quantum corrections are computed to discern if both theories give the same physical predictions.

Title: Neutrino mass hierarchy: current status

Speaker: Stefano Gariazzo (IFIC UV/CSIC)

Abstract: No Abstract

Title: Non-Singular Coordinates for the Kiselev Space-time

Speaker: S. M. Jawwad Riaz (COMSATS institue of information technology, WAH)

Abstract: In the talk, non-singular coordinates of the Kiselev space-time will be presented.

Title: Non-Universality in the Flavour-Effective MSSM

Speaker: María Luísa López Ibáñez (Universitat de València)

Abstract: Supersymmetric theories invariant under an underlying flavour-symmetry provide a rich playground for model building aimed at explaining the flavour structure of the Standard Model. In a specific class of these models, where supersymmetry is mediated by gravity, the soft-breaking Lagrangian can exhibit large tree-level flavour violating effects, despite their ultraviolet flavour-conserving behaviour.

Title: Palatini connections in EH-Palatini gravity and extensions

Speaker: Alejandro Jiménez Cano (UGR)

Abstract: It is often said that the unique solution of Einstein-Hilbert gravity in the Palatini formalism is the Levi-Civita connection. However, typically symmetric connection or metricity condition is assumed. If we vary in the general case (under some hypothesis on the matter lagrangian), we obtain a set of connections, a result that reflects the so-called projective symmetry of the theory. The general solution of the equations of motion extends the Levi-Civita description to a new family of connections with different geometrical properties (different curvature, for instance) and some interesting features such as the homothetic parallel transport. All of this conspires and the rough physics, given by Einstein equations and geodesic motion, turns out to be invariant. The projective symmetry is more than a simple gauge symmetry, because the field strength is not invariant, but the physical objects built from it are; and it seems to be impossible to detect the difference between the description using one or another of this connections, at least, at a classical level. The idea behind this work is to motivate whether this non-uniqueness of the mathematics that determines an unique physics can be extended to more general couplings, lagrangians and formulations.

Title: Probing high energy effects in multijet production

Speaker: David Gordo (IFT UAM/CSIC)

Abstract: In order to test the presence of BFKL dynamics at pp collisions in the LHC, we propose to study new multi jet observables where the rapidity separation between them is large, as a generalization of the Mueller-Navelet jets. Since non-tagged associated mini-jet multiplicity is allowed, we argue that the azimuthal-angle correlations among the hard tagged jets can provide with several test of the BFKL dynamics, and can be compared with other predictions where BFKL effects are not taken into account. In our study realistic kinematical cuts are applied, in order to facilitate a comparison with the experiment.

Title: Regularizing data for practical randomness generation

Speaker: Boris Bourdoncle (ICFO - Institut de Ciènces Fotòniques)

Abstract: One of the most striking feature of quantum physics is its non-locality: performing measurements on particles that are distant but entangled can result in correlations that cannot be described by a local model. These non-local correlations contain intrinsic randomness: one can guarantee that the results of the performed measurements cannot be predicted, independently of the real physical implementation that led to such correlations, i.e., in a device-independent way. This makes them a valuable ressource for a crucial cryptographic task, that is randomness generation. Theoretical tools have been developed in order to quantify the randomness contained in such correlations as a function of how non-local they are. However, in practice, an issue arises: the exact correlations are never accessible to the users, because of the finite statistics effect. We present here a solution to this problem, which allows us to certify practical randomness in a device-independent way.

Title: Simple extensions of the Standard Model

Speaker: Clara Murgui Galvez (IFIC UV/CSIC)

Abstract: No Abstract

Title: The type IIA scalar potential and the master 4-form

Speaker: Alvaro Herraez (IFT UAM/CSIC)

Abstract: After a brief introduction to axions and 4-forms, we show that the full scalar potential of 4D Type IIA orientifolds with fluxes and D6-branes can be written as a bilinear form of certain polynomials that depend only on the fluxes, the axions and topological data (not on the geometry). The coeficients in the 4-form do depend on the geometry through the relevant metrics. We also show that all the these polynomials can be derived from one particular polynomial that couples to a master 4-form, from which also the superpotential of the corresponding N = 1 supergravity formulation can be recovered (after identification of the appropriate SUGRA axion fields). In this formulation, which is not explicitly SUSY, the axionic symmetries of a any given CY orientifold are explicit and do not mix with dualities. We finally discuss some possible applications of this formalism.

Title: Topology and general relativity, it takes two to tango

Speaker: Juan Margalef (UC3M/CSIC)

Abstract: Many apparent space-time pathological behaviours are due to a lack of understanding of the geometry. On the other hand, intrinsic pathologies are the trademark of singular space-times. In this talk I will show how topology helps us understanding both situtations in the so called Misner space.

Title: Vacuum Particle creation: reheating, Schwinger effect and renormalization

Speaker: Antonio Ferreiro (IFIC/UV)

Abstract: Particle production in gravitational and electromagnetic fields exemplifies nontrivial properties of the vacuum. A regularization mechanism to cure divergences from local quantities is inmediatly needed. I will revise the renormalizaion for the energy density and the electric current in gravitational (FRWL background) and electric fields (Schwinger effect) respectively and consider its consecuences in the understanding of the vacuum production.

Title: Extended gauge theories and supergravity

Speaker: Sebastian Salgado (MPIF)

Abstract: It is proposed a procedure to find extended gauge invariants and Chern-Simons forms including higher degree differential forms as gauge potentials. The first cases are analyzed and possible applications are discussed.

Title: In-vacuo-dispersion-like spectral lags in gamma-ray bursts

Speaker: Michele Ronco (Sapienza University of Rome/INFN and UV/IFIC)

Abstract: Some recent studies exposed rather strong statistical evidence of in-vacuo-dispersion-like spectral lags for gamma-ray bursts (GRBs), a linear correlation between time of observation and energy of GRB particles. Those results focused on testing in-vacuo dispersion for the most energetic GRB particles, and in particular only included photons with energy at emission greater than 40 GeV. We here extend the window of the statistical analysis down to 5 GeV and find results that are consistent with what had been previously noticed at higher energies.

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