Searcharxiv⌕ Search

arXiv subjects

Antón F. Faedo

Publications and source records attributed to Antón F. Faedo.

14 recordsLinked to original sources

Supergravity flows, wormholes and their pseudo-Hermitian holographic duals

We find solutions to consistent truncations of supergravity where some real scalars are analytically extended to imaginary values, ensuring the metric remains real-valued. Among the solutions there are Lorentzian traversable wormholes connecting two asymptotically Anti-de Sitter spacetimes and flows that have a real metric also when uplifted to ten or eleven dimensions. We argue that the holographic duals are pseudo-Hermitian and $PT$-symmetric theories. Wormhole solutions also admit an interpretation as the low-energy theory of two stacks of branes and antibranes after tachyon condensation. The wormhole is then dual to an entangled state of two copies of the theory that lives on a stack of branes. We present some evidence by computing the mutual information between the theories at each boundary and by identifying the Goldstone bosons associated to the breaking of the two copies of Poincaré symmetry to their diagonal subgroup.

hep-th↗

Light dilaton near critical points in top-down holography

We study a class of UV-complete, strongly coupled, confining three-dimensional field theories, that exhibit a novel stabilisation mechanism for the mass of the lightest scalar composite state, relying on the existence of a critical point. The theories admit a holographic dual description in terms of regular backgrounds in eleven-dimensional supergravity. Their phase diagram includes a line of first-order phase transitions ending at the critical point, where the transition becomes of second order. We calculate the mass spectrum of bound states of the field theory, by considering fluctuations around the background solutions, and find that, near the critical point, a hierarchy of scales develops, such that one state becomes parametrically light. We identify this state as the dilaton, the pseudo-Nambu-Goldstone boson associated with the spontaneous breaking of approximate scale invariance. This stabilisation mechanism might be exploited to address hierarchy problems in particle and astroparticle physics.

hep-th↗

Spontaneous breaking of baryon symmetry in strongly coupled three-dimensional theories

We show that baryon number symmetry is spontaneously broken in a class of three-dimensional, ${\cal N}=1$ supersymmetric theories with a discrete mass spectrum. These models serve as lower-dimensional, less-supersymmetric analogs of the Klebanov-Strassler solution, sharing properties such as the presence of a cascade. The spontaneous symmetry breaking is evidenced by the appearance of a Goldstone mode, which corresponds to a vector fluctuation in the gravity dual.

hep-th↗

Light holographic dilatons near critical points

We investigate the relation between the emergence of a dilaton in gapped (confining) field theories, and the presence of either complex fixed points or instabilities in the strongly coupled dynamics in two classes of bottom-up holographic models. We demonstrate that in one of the two classes there is a critical line of first-order phase transitions (at zero temperature) that terminates at a critical point. We calculate the mass spectrum of fluctuations of the associated regular gravity backgrounds, which we interpret as bound states in the dual field theories. In proximity to the second-order phase transition, we find a parametrically light scalar state, and its composition leads us to identify it as a dilaton.

hep-th↗

Baryonic matter at strong coupling: confining superfluids and deconfined ferromagnets

We study the phase diagram of a strongly coupled confining theory in $2+1$ dimensions, as a function of temperature and baryon chemical potential. The theory has a fully fledged supergravity holographic dual, that we use to predict a line of first order phase transitions separating a confining phase and a deconfined phase. Both phases exhibit a non-zero baryon density thus providing a first example of baryonic matter in a confining string dual that does not require the introduction of flavor branes. We argue that the confining phase is a baryon superfluid, while the deconfined phase has non-zero baryon magnetization.

hep-th↗

Monopoles and confinement in three dimensions from holography

We study the phase diagram of a confining three-dimensional $\mathcal{N}=1$ supersymmetric $\text{U}(N)\times\text{U}(N+M)$ theory with holographic dual corresponding to a known string theory solution. The theory possesses a global $\text{U}(1)$ symmetry under which magnetic monopoles are charged. We introduce both temperature and an external magnetic field for monopoles and find that there are deconfinement phase transitions as any of the two is increased, supporting monopole condensation as the possible mechanism for confinement. We find that the transition as the magnetic field is increased is second order, providing the first example in holographic duals of a deconfinement transition which is not first order. We also uncover a rich structure in the phase diagram, with a triple point and a critical point where a line of first order transitions end.

hep-th↗

Mass Gap without Confinement

We revisit a one-parameter family of three-dimensional gauge theories with known supergravity duals. We show that three infrared behaviors are possible. For generic values of the parameter, the theories exhibit a mass gap but no confinement, meaning no linear quark-antiquark potential; for one limiting value of the parameter the theory flows to an infrared fixed point; and for another limiting value it exhibits both a mass gap and confinement. Theories close to these limiting values exhibit quasi-conformal and quasi-confining dynamics, respectively. Eleven-dimensional supergravity provides a simple, geometric explanation of these features.

hep-th↗

Three-dimensional super Yang-Mills with compressible quark matter

We construct the gravity dual of three-dimensional, $SU(N_{\textrm{c}})$ super Yang-Mills theory with $N_{\textrm{f}}$ flavors of dynamical quarks in the presence of a non-zero quark density $N_{\textrm{q}}$. The supergravity solutions include the backreaction of $N_{\textrm{c}}$ color D2-branes and $N_{\textrm{f}}$ flavor D6-branes with $N_{\textrm{q}}$ units of electric flux on their worldvolume. For massless quarks, the solutions depend non-trivially only on the dimensionless combination $ρ=N_{\textrm{c}}^2 N_{\textrm{q}} / λ^2 N_{\textrm{f}}^4$, with $λ=g_{\textrm{YM}}^2 N_{\textrm{c}}$ the 't Hooft coupling, and describe renormalization group flows between the super Yang-Mills theory in the ultraviolet and a non-relativistic theory in the infrared. The latter is dual to a hyperscaling-violating, Lifshitz-like geometry with dynamical and hyperscaling-violating exponents $z=5$ and $θ=1$, respectively. If $ρ\ll 1$ then at intermediate energies there is also an approximate AdS$_4$ region, dual to a conformal Chern-Simons-Matter theory, in which the flow exhibits quasi-conformal dynamics. At zero temperature we compute the chemical potential and the equation of state and extract the speed of sound. At low temperature we compute the entropy density and extract the number of low-energy degrees of freedom. For quarks of non-zero mass $M_{\textrm{q}}$ the physics depends non-trivially on $ρ$ and $M_{\textrm{q}} N_{\textrm{c}}/λN_{\textrm{f}}$.

hep-th↗

Transverse gravity versus observations

Theories of gravity invariant under those diffeomorphisms generated by transverse vectors, $\pd_\mξ^\m=0$ are considered. Such theories are dubbed transverse, and differ from General Relativity in that the determinant of the metric, $g$, is a transverse scalar. We comment on diverse ways in which these models can be constrained using a variety of observations. Generically, an additional scalar degree of freedom mediates the interaction, so the usual constraints on scalar-tensor theories have to be imposed. If the purely gravitational part is Einstein--Hilbert but the matter action is transverse, the models predict that the three {\em a priori} different concepts of mass (gravitational active and gravitational passive as well as inertial) are not equivalent anymore. These transverse deviations from General Relativity are therefore tightly constrained, actually correlated with existing bounds on violations of the equivalence principle, local violations of Newton's third law and/or violation of Local Position Invariance.

hep-th↗

Unimodular cosmology and the weight of energy

Some models are presented in which the strength of the gravitational coupling of the potential energy relative to the same coupling for the kinetic energy is, in a precise sense, adjustable. The gauge symmetry of these models consists of those coordinate changes with unit jacobian.

hep-th↗

Renormalized masses of heavy Kaluza-Klein states

Several ways of computing the radiative corrections to the heavy boson masses in Kaluza-Klein theory are discussed. It is argued that only an intrinsically higher dimensional approach embodies all the desired physical properties.

hep-th↗

Quantum corrections to Higher-Dimensional Theories

This is a non-technical summary of the subtleties of quantum corrections on extra-dimensional theories: should one first renormalize and then mode expand, or first expand in four-dimensional modes and then renormalize?

hep-ph↗

Renormalized Kaluza-Klein theories

Using six-dimensional quantum electrodynamics ($QED_6$) as an example we study the one-loop renormalization of the theory both from the six and four-dimensional points of view. Our main conclusion is that the properly renormalized four dimensional theory never forgets its higher dimensional origin. In particular, the coefficients of the neccessary extra counterterms in the four dimensional theory are determined in a precise way. We check our results by studying the reduction of $QED_4$ on a two-torus.

hep-th↗