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Jeremias Aguilera-Damia

Publications and source records attributed to Jeremias Aguilera-Damia.

7 recordsLinked to original sources

de Sitter Vacua & pUniverses

We analyze a simple extension of the Schwinger model, which we refer to as the $p$-Schwinger model, on a de Sitter background. In this theory, the charged massless fermions carry non-unit integer charge $p$. In Minkowski space, the $p$-Schwinger model has discrete zero- and one-form global symmetries that are spontaneously broken, yielding $p$ degenerate ground states. We demonstrate that these features persist upon placing the $p$-Schwinger model on a global de Sitter background, establishing that such discrete global symmetries can be spontaneously broken for quantum field theories in de Sitter space. In particular, the theory is endowed with $p$ distinct, but locally-indistinguishable, de Sitter invariant states, the de Sitter vacua, satisfying the Hadamard property. We couple a variant of the $p$-Schwinger model with ${\rm N}_{\rm f}$ flavors to quantum gravity with $Λ>0$, and demonstrate the existence of a semiclassical de Sitter saddle at large ${\rm N}_{\rm f}$. In the gravitational theory, the $p$ de Sitter invariant vacua are speculatively interpreted as microstates of the de Sitter horizon in the low-energy effective field theory.

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RG Dynamics of Irrelevant Fermion Operators and the Drag Coupling Mechanism

We study the renormalization-group flow of higher-dimensional fermionic interactions $(ψ^\dagger ψ)^{2n}$ in the presence of a Fermi surface. We show that the growth of the BCS four-fermion coupling induces a drag mechanism whereby higher-order fermionic couplings are driven to strong coupling in the infrared. We derive the corresponding beta functions and show that the drag effect applies generically to the whole tower of fermionic operators. Remarkably, although all couplings are driven toward the same strong-coupling scale, the renormalization-group flow preserves a hierarchy in which higher-dimensional operators remain parametrically suppressed relative to the BCS interaction. We then investigate this mechanism in a $2+1$-dimensional non-Fermi liquid coupled to a critical boson. While higher-order fermionic interactions are similarly enhanced along the flow, we show that they do not destabilize the IR stable non-Fermi-liquid fixed point, present for sufficiently large $N$. We briefly discuss possible implications for multicomponent superconductors and other strongly correlated metallic systems.

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A substrate for brane shells from $T\bar{T}$

A solvable current-current deformation of the worldsheet theory of strings on $AdS_3$ has been recently conjectured to be dual to an irrelevant deformation of the spacetime orbifold CFT, commonly referred to as single-trace $T\bar{T}$. These deformations give rise to a family of bulk geometries which realize a non-trivial flow towards the UV. For a particular sign of this deformation, the corresponding three-dimensional geometry approaches $AdS_3$ in the interior, but has a curvature singularity at finite radius, beyond which there are closed timelike curves. It has been suggested that this singularity is due to the presence of "negative branes," which are exotic objects that generically change the metric signature. We propose an alternative UV-completion for these geometries by cutting and gluing to a regular background which approaches a linear dilaton vacuum in the UV. In the S-dual picture, a singularity resolution mechanism known as the enhançon induces this transition by the formation of a shell of $D5$-branes at a fixed radial position near the singularity. The solutions involving negative branes gain a new interpretation in this context.

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$T \bar{T}$-Deformed Actions and (1,1) Supersymmetry

We describe an algorithmic method to calculate the $T\bar{T}$ deformed Lagrangian of a given seed theory by solving an algebraic system of equations. This method is derived from the topological gravity formulation of the deformation. This algorithm is far simpler than the direct partial differential equations needed in most earlier proposals. We present several examples, including the deformed Lagrangian of (1,1) supersymmetry. We show that this Lagrangian is off-shell invariant through order $λ^2$ in the deformation parameter and verify its SUSY algebra through order $λ$.

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Circular Wilson loops in defect Conformal Field Theory

We study a D3-D5 system dual to a conformal field theory with a codimension-one defect that separates regions where the ranks of the gauge groups differ by $k$. With the help of this additional parameter, as observed by Nagasaki, Tanida and Yamaguchi, one can define a double scaling limit in which the quantum corrections are organized in powers of $λ/k^2$, which should allow to extrapolate results between weak and strong coupling regimes. In particular we consider a radius $R$ circular Wilson loop placed at a distance $L$, whose internal space orientation is given by an angle $χ$. We compute its vacuum expectation value and show that, in the double scaling limit and for small $χ$ and small $L/R$, weak coupling results can be extrapolated to the strong coupling limit.

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Semiclassical partition function for strings dual to Wilson loops with small cusps in ABJM

We compute the 1-loop partition function for strings in $AdS_4\times\mathbb{CP}^3$, whose worldsheets end along a line with small cusp angles in the boundary of AdS. We obtain these 1-loop results in terms of the vacuum energy for on-shell modes. Our results verify the proposal by Lewkowycz and Maldacena in arXiv:1312.5682 for the exact Bremsstrahlung function up to the next to leading order in the strong coupling expansion. The agreement is observed for cusps distorting either the 1/2 BPS or the 1/6 BPS Wilson line.

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Strings in AdS_4 x CP^3, Wilson loops in N=6 super Chern-Simons-matter and Bremsstrahlung functions

We find 1/6 BPS string configurations in AdS_4 x CP^3, which we identify as the duals of certain 1/6 BPS circular Wilson loops in N=6 super Chern-Simons-matter gauge theory. We use our results to verify -in the strong coupling limit- a proposal made in arXiv:1402.4128 for a relation between the expectation value of these Wilson loops and the Bremsstrahlung function from deforming 1/2 BPS Wilson lines with a cusp. We also derive an analogous relation between the expectation value of some particular 1/12 BPS Wilson loops and the Bremsstrahlung function from deforming 1/6 BPS Wilson lines with an internal space cusp.

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