pinecone/core-2020-05-10-deduplication huggingface dataset:
Dynamics of Holographic Entanglement Entropy Following a Local Quench

We discuss the behaviour of holographic entanglement entropy following a
local quench in 2+1 dimensional strongly coupled CFTs. The entanglement
generated by the quench propagates along an emergent light-cone, reminiscent of
the Lieb-Robinson light-cone propagation of correlations in non-relativistic
systems. We find the speed of propagation is bounded from below by the
entanglement tsunami velocity obtained earlier for global quenches in
holographic systems, and from above by the speed of light. The former is
realized for sufficiently broad quenches, while the latter pertains for well
localized quenches. The non-universal behavior in the intermediate regime
appears to stem from finite-size effects. We also note that the entanglement
entropy of subsystems reverts to the equilibrium value exponentially fast, in
contrast to a much slower equilibration seen in certain spin models.Comment: 27 pages, 12 figures. v2: added refs and fixed typos. v3: added
  clarifications, published versio
New Physics Patterns in $\varepsilon^\prime/\varepsilon$ and
  $\varepsilon_K$ with Implications for Rare Kaon Decays and $\Delta M_K$

The SM prediction for the ratio $\varepsilon^\prime/\varepsilon$ appears to
be significantly below the experimental data. Also $\varepsilon_K$ in the SM
tends to be below the data. Any NP removing these anomalies will first of all
have impact on flavour observables in the $K$ meson system, in particular on
rare $K$ decays and $\Delta M_K$. Restricting the operators contributing to
$\varepsilon^\prime/\varepsilon$ to the SM ones and to the corresponding primed
operators, NP contributions are quite generally dominated either by QCD penguin
(QCDP) operators $Q_6(Q_6^\prime)$ or electroweak penguin (EWP) operators
$Q_8(Q_8^\prime)$ with rather different implications for other flavour
observables. We discuss general models with tree-level $Z$ and $Z^\prime$
flavour violating exchanges and few specific models. We find that simultaneous
enhancements of $\varepsilon^\prime/\varepsilon$, $\varepsilon_K$,
$\mathcal{B}(K_L\to\pi^0\nu\bar\nu)$ and $\mathcal{B}(K^+\to\pi^+\nu\bar\nu)$
in $Z$ scenarios are only possible in the presence of both LH and RH
flavour-violating couplings. In $Z^\prime$ scenarios this is not required but
the size of NP effects and the correlation between
$\mathcal{B}(K_L\to\pi^0\nu\bar\nu)$ and $\mathcal{B}(K^+\to\pi^+\nu\bar\nu)$
depends strongly on whether QCDP or EWP dominate NP contributions to
$\varepsilon^\prime/\varepsilon$. In the QCDP case possible enhancements of
both branching ratios are much larger than for EWP scenario and take place only
on the branch parallel to the Grossman-Nir bound, which is in the case of EWP
dominance only possible in the absence of NP in $\varepsilon_K$. QCDP and EWP
scenarios of NP in $\varepsilon^\prime/\varepsilon$ can also be uniquely
distinguished by the size and the sign of NP contribution to $\Delta M_K$,
elevating the importance of the precise calculation of $\Delta M_K$ in the SM.Comment: 67 pages, 6 Figures (12 Plots), references and clarifying comments on
  pages 3 and 9 and equation (24) added, conclusions unchange
Goldstones in Diphotons

We study the conditions for a new scalar resonance to be observed first in
diphotons at the LHC Run-2. We focus on scenarios where the scalar arises
either from an internal or spacetime symmetry broken spontaneously, for which
the mass is naturally below the cutoff and the low-energy interactions are
fixed by the couplings to the broken currents, UV anomalies, and selection
rules. We discuss the recent excess in diphoton resonance searches observed by
ATLAS and CMS at 750 GeV, and explore its compatibility with other searches at
Run-1 and its interpretation as Goldstone bosons in supersymmetry and composite
Higgs models. We show that two candidates naturally emerge: a Goldstone boson
from an internal symmetry with electromagnetic anomalies, and the scalar
partner of the Goldstone of supersymmetry breaking: the sgoldstino. The dilaton
from conformal symmetry breaking is instead disfavoured by present data, in its
minimal natural realization.Comment: 18 pages + refs, 2 figures. v2: typos corrected, references added,
  discussions extended and three new plots. Conclusion unchanged. v3: published
  versio
Tripartite information of highly entangled states

Holographic systems require monogamous mutual information for validity of
semiclassical geometry. This is encoded by the sign of the tripartite
information ($I3$). We investigate the behaviour of $I3$ for all partitionings
of systems in states which are highly entangled in a multipartite or bipartite
sense. In the case of multipartite entanglement we propose an algorithmic
construction that we conjecture can be used to build local maxima of $I3$ for
any partitioning. In case of bipartite entanglement we classify the possible
values of $I3$ for perfect states and investigate, in some examples, the effect
on its sign definiteness due to deformations of the states. Finally we comment
on the proposal of using $I3$ as a parameter of scrambling, arguing that in
general its average over qubits permutations could be a more sensible measure.Comment: 16 pages. v2: typos fixed, published versio
A membrane paradigm at large D

We study $SO(d+1)$ invariant solutions of the classical vacuum Einstein
equations in $p+d+3$ dimensions. In the limit $d \to \infty$ with $p$ held
fixed we construct a class of solutions labelled by the shape of a membrane
(the event horizon), together with a `velocity' field that lives on this
membrane. We demonstrate that our metrics can be corrected to nonsingular
solutions at first sub-leading order in $\frac{1}{d}$ if and only if the
membrane shape and `velocity' field obey equations of motion which we
determine. These equations define a well posed initial value problem for the
membrane shape and this `velocity' and so completely determinethe dynamics of
the black hole. They may be viewed as governing the non-linear dynamics of the
light quasi normal modes of Emparan, Suzuki and Tanabe.Comment: The main results emphasised better, The presentation of the
  quasinormal modes improved for clarity and typos correcte
Extremal Higher Spin Black Holes

The gauge sector of three-dimensional higher spin gravities can be formulated
as a Chern-Simons theory. In this context, a higher spin black hole corresponds
to a flat connection with suitable holonomy (smoothness) conditions which are
consistent with the properties of a generalized thermal ensemble. Building on
these ideas, we discuss a definition of black hole extremality which is
appropriate to the topological character of 3d higher spin theories. Our
definition can be phrased in terms of the Jordan class of the holonomy around a
non-contractible (angular) cycle, and we show that it is compatible with the
zero-temperature limit of smooth black hole solutions. While this notion of
extremality does not require supersymmetry, we exemplify its consequences in
the context of sl(3|2) + sl(3|2) Chern-Simons theory and show that, as usual,
not all extremal solutions preserve supersymmetries. Remarkably, we find in
addition that the higher spin setup allows for non-extremal supersymmetric
black hole solutions. Furthermore, we discuss our results from the perspective
of the holographic duality between sl(3|2) + sl(3|2) Chern-Simons theory and
two-dimensional CFTs with W_{(3|2)} symmetry, the simplest higher spin
extension of the N=2 super-Virasoro algebra. In particular, we compute
W_{(3|2)} BPS bounds at the full quantum level, and relate their semiclassical
limit to extremal black hole or conical defect solutions in the 3d bulk. Along
the way, we discuss the role of the spectral flow automorphism and provide a
conjecture for the form of the semiclassical BPS bounds in general N=2
two-dimensional CFTs with extended symmetry algebras.Comment: 63 + 18 pages, 2 figures. v2: typos corrected, minor rewording in the
  abstract for improved clarity, version published in JHE
The Pentabox Master Integrals with the Simplified Differential Equations
  approach

We present the calculation of massless two-loop Master Integrals relevant to
five-point amplitudes with one off-shell external leg and derive the complete
set of planar Master Integrals with five on-mass-shell legs, that contribute to
many $2\to 3$ amplitudes of interest at the LHC, as for instance three jet
production, $\gamma, V, H +2$ jets etc., based on the Simplified Differential
Equations approach.Comment: Revised version accepted for publication in JHEP. Ancillary files
  with results can be downloaded from
  https://www.dropbox.com/s/90iiqfcazrhwtso/results.tgz?dl=
On T-duality of $R^2$-corrections to DBI action at all orders of gauge
  field

Recently, it has been observed that in a T-duality invariant world-volume
theory in flat spacetime, all orders of gauge field strength and all orders of
the D-brane velocity appear in two specific matrices. Using these two matrices,
we construct the world-volume couplings of two massless NSNS states at order
$\alpha'^2$ and all orders of the velocity and the gauge field strength, by
requiring them to be invariant under the linear T-duality. The standard
extension $F\rightarrow F+P[B]$, then produces all orders of the pull-back of
B-field into the action. We compare the resulting couplings for zero velocity
and gauge field strength, with the $\alpha'^2$ terms of the disk-level S-matrix
element of two massless NSNS vertex operators in the presence of a constant
background B-field. We have found an exact agreement.Comment: 13 page
Do All BPS Black Hole Microstates Carry Zero Angular Momentum?

From the analysis of the near horizon geometry and supersymmetry algebra it
has been argued that all the microstates of single centered BPS black holes
with four unbroken supersymmetries carry zero angular momentum in the region of
the moduli space where the black hole description is valid. A stronger form of
the conjecture would be that the result holds for any sufficiently generic
point in the moduli space. In this paper we set out to test this conjecture for
a class of black hole microstates in type II string theory on $T^6$,
represented by four stacks of D-branes wrapped on various cycles of $T^6$. For
this system the above conjecture translates to the statement that the moduli
space of classical vacua must be a collection of points. Explicit analysis of
systems carrying a low number of D-branes supports this conjecture.Comment: LaTeX, 42 pages; v2: minor corrections, some new results adde
Dark matter and localised fermions from spherical orbifolds?

We study a class of six-dimensional models based on positive curvature
surfaces (spherical 2-orbifolds) as extra-spaces. Using the Newman-Penrose
formalism, we discuss the particle spectrum in this class of models. The
fermion spectrum problem, which has been addressed with flux compactifications
in the past, can be avoided using localised fermions. In this framework, we
find that there are four types of geometry compatible with the existence of a
stable dark matter candidate and we study the simplest case in detail. Using
the complementarity between collider resonance searches and relic density
constraints, we show that this class of models is under tension, unless the
model lies in a funnel region characterised by a resonant Higgs s-channel in
the dark matter annihilation.Comment: 38 pages, 7 figure
Effective interpretations of a diphoton excess

We discuss some consistency tests that must be passed for a successful
explanation of a diphoton excess at larger mass scales, generated by a scalar
or pseudoscalar state, possibly of a composite nature, decaying to two photons.
Scalar states at mass scales above the electroweak scale decaying significantly
into photon final states generically lead to modifications of Standard Model
Higgs phenomenology. We characterise this effect using the formalism of
Effective Field Theory (EFT) and study the modification of the effective
couplings to photons and gluons of the Higgs. The modification of Higgs
phenomenology comes about in a variety of ways. For scalar $0^+$states, the
Higgs and the heavy boson can mix. Lower energy phenomenology gives a limit on
the mixing angle, which gets generated at one loop in any such theory
explaining the diphoton excess. Even if the mixing angle is set to zero, we
demonstrate that a relation exists between lower energy Higgs data and a
massive scaler decaying to diphoton final states. If the new boson is a
pseudoscalar, we note that if it is composite, it is generic to have an excited
scalar partner that can mix with the Higgs, which has a stronger coupling to
photons. In the case of a pseudoscalar, we also characterize how lower energy
Higgs phenomenology is directly modified using EFT, even without assuming a
scalar partner of the pseudoscalar state. We find that naturalness concerns can
be accommodated, and that pseudoscalar models are more protected from lower
energy constraints.Comment: 14 pages, 4 figures V2 : Typos and text corrected, one loop and
  inelastic photon scattering results added in appendix, diphoton excess
  citations adde
Axion decay constants away from the lamppost

It is unknown whether a bound on axion field ranges exists within quantum
gravity. We study axion field ranges using extended supersymmetry, in
particular allowing an analysis within strongly coupled regions of moduli
space. We apply this strategy to Calabi-Yau compactifications with one and two
K\"ahler moduli. We relate the maximally allowable decay constant to geometric
properties of the underlying Calabi-Yau geometry. In all examples we find a
maximal field range close to the reduced Planck mass (with the largest field
range being 3.25 $M_P$). On this perspective, field ranges relate to the
intersection and instanton numbers of the underlying Calabi-Yau geometry.Comment: 28 pages, 6 figure
Search for Sphalerons in Proton-Proton Collisions

In a recent paper, Tye and Wong (TW) have argued that sphaleron-induced
transitions in high-energy proton-proton collisions should be enhanced compared
to previous calculations, based on a construction of a Bloch wave function in
the periodic sphaleron potential and the corresponding pass band structure.
Here we convolute the calculations of TW with parton distribution functions and
simulations of final states to explore the signatures of sphaleron transitions
at the LHC and possible future colliders. We calculate the increase of
sphaleron transition rates in proton-proton collisions at centre-of-mass
energies of 13/14/33/100 TeV for different sphaleron barrier heights, while
recognising that the rates have large overall uncertainties. We use a
simulation to show that LHC searches for microscopic black holes should have
good efficiency for detecting sphaleron-induced final states, and discuss their
experimental signatures and observability in Run 2 of the LHC and beyond. We
recast the early ATLAS Run-2 search for microscopic black holes to constrain
the rate of sphaleron transitions at 13 TeV, deriving a significant limit on
the sphaleron transition rate for the nominal sphaleron barrier height of 9
TeV.Comment: 16 pages, 8 figure
Resonant mono Higgs at the LHC

In recent years, the production of a SM particle with large missing
transverse momentum, dubbed mono-X searches, have gained increasing attention.
After the discovery of the Higgs boson in 2012, the run-II of the LHC will now
scrutinise its properties, looking for BSM physics. In particular, one could
search for mono-Higgs signals, that are typically studied in models addressing
dark matter. However, this signal can appear also in models addressing the
neutrino masses, if additional heavier neutrinos with masses at the electroweak
scale are present. The latter will couple to the SM neutrinos and the Higgs
boson, yielding a type of mono-Higgs signal not considered for dark matter: the
resonant production of a Higgs boson and missing energy. In this paper, we
address the LHC exclusion power of the latter with dedicated detector
simulations, and reinterpret it in a benchmark scenario for neutrino mass
generation.Comment: 17 pages, 8 figures, 6 tables, added reference
Shape Dependence of Entanglement Entropy in Conformal Field Theories

We study universal features in the shape dependence of entanglement entropy
in the vacuum state of a conformal field theory (CFT) on $\mathbb{R}^{1,d-1}$.
We consider the entanglement entropy across a deformed planar or spherical
entangling surface in terms of a perturbative expansion in the infinitesimal
shape deformation. In particular, we focus on the second order term in this
expansion, known as the entanglement density. This quantity is known to be
non-positive by the strong-subadditivity property. We show from a purely field
theory calculation that the non-local part of the entanglement density in any
CFT is universal, and proportional to the coefficient $C_T$ appearing in the
two-point function of stress tensors in that CFT. As applications of our
result, we prove the conjectured universality of the corner term coefficient
$\frac{\sigma}{C_T}=\frac{\pi^2}{24}$ in $d=3$ CFTs, and the holographic Mezei
formula for entanglement entropy across deformed spheres.Comment: 43 pages, 5 figures; v2: Typos fixed, additional reference
Zero Temperature Dissipation and Holography

We use holographic techniques to study the zero-temperature limit of
dissipation for a Brownian particle moving in a strongly coupled CFT at finite
temperature in various space-time dimensions. The dissipative term in the
boundary theory for $\omega\to 0$, $T \to 0$ with $\omega / T$ held small and
fixed, does not match the same at $T=0$, $\omega \to 0$. Thus the $T\to 0$
limit is not smooth for $\omega < T$. This phenomenon appears to be related to
a confinement-deconfinement phase transition at $T=0$ in the field theory.Comment: 23 pages, 1 figure, v2 : minor improvements of the text, one figure
  added, accepted for publication in JHE
ATLAS Diboson Excess from Stueckelberg Mechanism

We discuss the diboson excess seen by the ATLAS detector around 2 TeV in the
LHC run I at $\sqrt{s}=8$ TeV. We explore the possibility that such an excess
can arise from a $Z'$ boson which acquires mass through a $U(1)_X$ Stueckelberg
extension. The corresponding $Z'$ gauge boson is leptophobic with a mass of
around 2 TeV and has interactions with $SU(2)_L$ Yang-Mills fields and gauge
fields of the hypercharge. The analysis predicts $Z'$ decays into $WW$ and $ZZ$
as well as into $Z\gamma$. Further three-body as well as four-body decays of
the $Z'$ such as $WWZ, WW\gamma, WWZZ$ etc are predicted. In the analysis we
use the helicity formalism which allows us to exhibit the helicity structure of
the $Z'$ decay processes in an transparent manner. In particular, we are able
to show the set of vanishing helicity amplitudes in the decay of the massive
$Z'$ into two vector bosons due to angular momentum conservation with a special
choice of the reference momenta. The residual set of non-vanishing helicity
amplitudes are identified. The parameter space of the model compatible with the
diboson excess seen by the ATLAS experiment at $\sqrt s=8$ TeV is exhibited.
Estimate of the diboson excess expected at $\sqrt s= 13$ TeV with 20 fb$^{-1}$
of integrated luminosity at LHC run II is also given. It is shown that the
$WW$, $ZZ$ and $Z\gamma$ modes are predicted to be in the approximate ratio
$1:\cos^2\theta_W (1+ \alpha \tan^2\theta_W)^2/2: (1-\alpha)^2\sin^2\theta_W/2$
where $\alpha$ is the relative strength of the couplings of hypercharge gauge
fields to the couplings of the Yang-Mills gauge fields. Thus observation of the
$Z\gamma$ mode as well as three-body and four-body decay modes of the $Z'$ will
provide a definite test of the model and of a possible new source of
interaction beyond the standard model.Comment: 12 pages, 6 figure
Defects in conformal field theory

We discuss consequences of the breaking of conformal symmetry by a flat or
spherical extended operator. We adapt the embedding formalism to the study of
correlation functions of symmetric traceless tensors in the presence of the
defect. Two-point functions of a bulk and a defect primary are fixed by
conformal invariance up to a set of OPE coefficients, and we identify the
allowed tensor structures. A correlator of two bulk primaries depends on two
cross-ratios, and we study its conformal block decomposition in the case of
external scalars. The Casimir equation in the defect channel reduces to a
hypergeometric equation, while the bulk channel blocks are recursively
determined in the light-cone limit. In the special case of a defect of
codimension two, we map the Casimir equation in the bulk channel to the one of
a four-point function without defect. Finally, we analyze the contact terms of
the stress-tensor with the extended operator, and we deduce constraints on the
CFT data. In two dimensions, we relate the displacement operator, which appears
among the contact terms, to the reflection coefficient of a conformal
interface, and we find unitarity bounds for the latter.Comment: 57 pages, 5 figures, Matches published versio
QED effects in the pseudoscalar meson sector

We present results on the pseudoscalar meson masses from a fully dynamical
simulation of QCD+QED. We concentrate particularly on violations of isospin
symmetry. We calculate the $\pi^+$-$\pi^0$ splitting and also look at other
isospin violating mass differences. We have presented results for these isospin
splittings in arXiv:1508.06401 [hep-lat]. In this paper we give more details of
the techniques employed, discussing in particular the question of how much of
the symmetry violation is due to QCD, arising from the different masses of the
$u$ and $d$ quarks, and how much is due to QED, arising from the different
charges of the quarks. This decomposition is not unique, it depends on the
renormalisation scheme and scale. We suggest a renormalisation scheme in which
Dashen's theorem for neutral mesons holds, so that the electromagnetic
self-energies of the neutral mesons are zero, and discuss how the self-energies
change when we transform to a scheme such as $\bar{MS}$, in which Dashen's
theorem for neutral mesons is violated.Comment: 22 pages, 7 figures. Replaced by version accepted for publication.
  One figure added, some discussions expanded. Conclusions unchange
NMSSM interpretations of the observed Higgs signal

While the properties of the signal that was discovered in the Higgs searches
at the LHC are consistent so far with the Higgs boson of the Standard Model
(SM), it is crucial to investigate to what extent other interpretations that
may correspond to very different underlying physics are compatible with the
current results. We use the Next-to-Minimal Supersymmetric Standard Model
(NMSSM) as a well-motivated theoretical framework with a sufficiently rich
Higgs phenomenology to address this question, making use of the public tools
HiggsBounds and HiggsSignals in order to take into account comprehensive
experimental information on both the observed signal and on the existing limits
from Higgs searches at LEP, the TeVatron and the LHC. We find that besides the
decoupling limit resulting in a single light state with SM-like properties,
several other configurations involving states lighter or quasi-degenerate with
the one at about 125 GeV turn out to give a competitive fit to the Higgs data
and other existing constraints. We discuss the phenomenology and possible
future experimental tests of those scenarios, and compare the features of
specific scenarios chosen as examples with those arising from a more global
fit.Comment: 46 pages, 23 figures. Version accepted by JHE