pinecone/core-2020-05-10-deduplication huggingface dataset:
String Consistency, Heavy Exotics, and the $750$ GeV Diphoton Excess at
  the LHC

String consistency conditions are stronger than anomaly cancellation and can
require the addition of exotics in the visible sector. We study such exotics
and demonstrate that they may account for the modest excess at $750$ GeV in
recent diphoton resonance searches performed by the ATLAS and CMS
collaborations. In a previous analysis of type II MSSM D-brane quivers we
systematically added up to five exotics for the sake of satisfying string
consistency conditions. Using this dataset, we demonstrate that 89780 of the
89964 quivers have exotics, 78155 of which include singlets that may couple to
MSSM or exotic multiplets with coupling structures governed by $U(1)$
symmetries that are often anomalous. We demonstrate that certain sets of
exotics are far preferred over others and study the structure of singlet
couplings to heavy exotics carrying standard model charges. Typical
possibilities include singlets that may decay to vector-like quarks and / or
vector-like leptons and subsequently to two photons. We show that a narrow
width diphoton excess can be accounted for while evading existing bounds if
multiple exotics are added, with vector-like leptons of mass $M_L\lesssim 375$
GeV and vector-like quarks with masses up to $\simeq 3$ TeV. However, a large
width $(\Gamma/M \sim 0.06)$, as suggested by the ATLAS data, cannot be easily
accommodated in this framework. Renormalization group equations with GUT-scale
boundary conditions show that these supersymmetric models are perturbative and
stable. Type IIA compactifications on toroidal orbifolds allow for $O(10)$
Yukawa couplings in the ultraviolet. We also discuss the possibility of
accounting for the diphoton excess in a low string scale scenario via the decay
of string axions.Comment: 29 pages. v2: Fortsch. der Phys. version. Text overlap expected due
  to merge with arXiv:1602.0625
Towards a world-sheet description of doubled geometry in string theory

Starting from a sigma-model for a doubled target-space geometry, we show that
the number of target-space dimensions can be reduced by half through a gauging
procedure. We apply this formalism to a class of backgrounds relevant for
double field theory, and illustrate how choosing different gaugings leads to
string-theory configurations T-dual to each other. We furthermore discuss that
given a conformal doubled theory, the reduced theories are conformal as well.
  As an example we consider the three-dimensional SU(2) WZW model and show that
the only possible reduced backgrounds are the cigar and trumpet CFTs in two
dimensions, which are indeed T-dual to each other.Comment: 37 pages; v2: references adde
Chiral expansion and Macdonald deformation of two-dimensional Yang-Mills
  theory

We derive the analog of the large $N$ Gross-Taylor holomorphic string
expansion for the refinement of $q$-deformed $U(N)$ Yang-Mills theory on a
compact oriented Riemann surface. The derivation combines Schur-Weyl duality
for quantum groups with the Etingof-Kirillov theory of generalized quantum
characters which are related to Macdonald polynomials. In the unrefined limit
we reproduce the chiral expansion of $q$-deformed Yang-Mills theory derived by
de Haro, Ramgoolam and Torrielli. In the classical limit $q=1$, the expansion
defines a new $\beta$-deformation of Hurwitz theory wherein the refined
partition function is a generating function for certain parameterized Euler
characters, which reduce in the unrefined limit $\beta=1$ to the orbifold Euler
characteristics of Hurwitz spaces of holomorphic maps. We discuss the
geometrical meaning of our expansions in relation to quantum spectral curves
and $\beta$-ensembles of matrix models arising in refined topological string
theory.Comment: 45 pages; v2: References adde
Test of the no-signaling principle in the Hensen "loophole-free CHSH
  experiment"

We analyze the data from the loophole-free CHSH experiment performed by
Hensen et al., and show that it is actually not exempt of an important
loophole. By increasing the size of the sample of event-ready detections, one
can exhibit in the experimental data a violation of the no-signaling principle
with a statistical significance at least similar to that of the reported
violation of the CHSH inequality, if not stronger.Comment: This version was updated on the basis of our talk at the conference
  "Quantum and Beyond", V\"axj\"o, Sweden, June 2016, and a few emails received
  from the readers of the first version of this arXiv, we improved statistical
  analysis and clarified essentially our poin
Towards a Gravity Dual for the Large Scale Structure of the Universe

The dynamics of the large-scale structure of the universe enjoys at all
scales, even in the highly non-linear regime, a Lifshitz symmetry during the
matter-dominated period. In this paper we propose a general class of
six-dimensional spacetimes which could be a gravity dual to the
four-dimensional large-scale structure of the universe. In this set-up, the
Lifshitz symmetry manifests itself as an isometry in the bulk and our universe
is a four-dimensional brane moving in such six-dimensional bulk. After finding
the correspondence between the bulk and the brane dynamical Lifshitz exponents,
we find the intriguing result that the preferred value of the dynamical
Lifshitz exponent of our observed universe, at both linear and non-linear
scales, corresponds to a fixed point of the RGE flow of the dynamical Lifshitz
exponent in the dual system where the symmetry is enhanced to the Schrodinger
group containing a non-relativistic conformal symmetry. We also investigate the
RGE flow between fixed points of the Lifshitz dynamical exponent in the bulk
and observe that this flow is reflected in a growth rate of the large-scale
structure, which seems to be in qualitative agreement with what is observed in
current data. Our set-up might provide an interesting new arena for testing the
ideas of holography and gravitational duals.Comment: V2: 29 pages, 3 figures. Some sentences in the intro. reformulate
Spin-orbit scattering in superconducting nanoparticles

We review interaction effects in chaotic metallic nanoparticles. Their
single-particle Hamiltonian is described by the proper random-matrix ensemble
while the dominant interaction terms are invariants under a change of the
single-particle basis. In the absence of spin-orbit scattering, the non-trivial
invariants consist of a pairing interaction, which leads to superconductivity
in the bulk, and a ferromagnetic exchange interaction. Spin-orbit scattering
breaks spin-rotation invariance and when it is sufficiently strong, the only
dominant nontrivial interaction is the pairing interaction. We discuss how the
magnetic response of discrete energy levels of the nanoparticle (which can be
measured in single-electron tunneling spectroscopy experiments) is affected by
such pairing correlations and how it can provide a signature of pairing
correlations. We also consider the spin susceptibility of the nanoparticle and
discuss how spin-orbit scattering changes the signatures of pairing
correlations in this observable.Comment: 10 pages, 6 figures, submitted for a special volume of Fortschritte
  der Physik (Progress of Physics), dedicated to the conference on Frontiers of
  Quantum and Mesoscopic Thermodynamics (FQMT15
Quantum Holonomy Theory and Hilbert Space Representations

We present a new formulation of quantum holonomy theory, which is a candidate
for a non-perturbative and background independent theory of quantum gravity
coupled to matter and gauge degrees of freedom. The new formulation is based on
a Hilbert space representation of the QHD(M) algebra, which is generated by
holonomy-diffeomorphisms on a 3-dimensional manifold and by canonical
translation operators on the underlying configuration space over which the
holonomy-diffeomorphisms form a non-commutative C*-algebra. A proof that the
state that generates the representation exist is left for later publications.Comment: 13 page
Entanglement Entropy Evolution under Double-trace Deformation

In this paper, we study the bulk entanglement entropy evolution in conical
BTZ black bole background using the heat kernel method. This is motivated by
exploring the new examples where quantum corrections of entanglement entropy
give the leading contribution. We find that in the large black hole limit the
bulk entanglement entropy decreases under the double-trace deformation which is
consistent with the holographic $c$ theorem and in the small black hole limit
the bulk entanglement entropy increases under the double-trace deformation.Comment: 10 pages, no figure, discussion is improve
A Geometric Formulation of Supersymmetry

The scalar fields of supersymmetric models are coordinates of a geometric
space. We propose a formulation of supersymmetry that is covariant with respect
to reparametrizations of this target space. Employing chiral multiplets as an
example, we introduce modified supersymmetry variations and redefined auxiliary
fields that transform covariantly under reparametrizations. The resulting
action and transformation laws are manifestly covariant and highlight the
geometric structure of the supersymmetric theory. The covariant methods are
developed first for general theories (not necessarily supersymmetric) whose
scalar fields are coordinates of a Riemannian target space.Comment: 14 pages; v2: references adde
Exceptional Calabi--Yau spaces: the geometry of $\mathcal{N}=2$
  backgrounds with flux

In this paper we define the analogue of Calabi--Yau geometry for generic
$D=4$, $\mathcal{N}=2$ flux backgrounds in type II supergravity and M-theory.
We show that solutions of the Killing spinor equations are in one-to-one
correspondence with integrable, globally defined structures in
$E_{7(7)}\times\mathbb{R}^+$ generalised geometry. Such "exceptional
Calabi--Yau" geometries are determined by two generalised objects that
parametrise hyper- and vector-multiplet degrees of freedom and generalise
conventional complex, symplectic and hyper-Kahler geometries. The integrability
conditions for both hyper- and vector-multiplet structures are given by the
vanishing of moment maps for the "generalised diffeomorphism group" of
diffeomorphisms combined with gauge transformations. We give a number of
explicit examples and discuss the structure of the moduli spaces of solutions.
We then extend our construction to $D=5$ and $D=6$ flux backgrounds preserving
eight supercharges, where similar structures appear, and finally discuss the
analogous structures in $O(d,d)\times\mathbb{R}^+$ generalised geometry.Comment: 68 pages plus appendice
Universality of Black Hole Quantum Computing

By analyzing the key properties of black holes from the point of view of
quantum information, we derive a model-independent picture of black hole
quantum computing. It has been noticed that this picture exhibits striking
similarities with quantum critical condensates, allowing the use of a common
language to describe quantum computing in both systems. We analyze such quantum
computing by allowing coupling to external modes, under the condition that the
external influence must be soft-enough in order not to offset the basic
properties of the system. We derive model-independent bounds on some crucial
time-scales, such as the times of gate operation, decoherence, maximal
entanglement and total scrambling. We show that for black hole type quantum
computers all these time-scales are of the order of the black hole half-life
time. Furthermore, we construct explicitly a set of Hamiltonians that generates
a universal set of quantum gates for the black hole type computer. We find that
the gates work at maximal energy efficiency. Furthermore, we establish a
fundamental bound on the complexity of quantum circuits encoded on these
systems, and characterize the unitary operations that are implementable. It
becomes apparent that the computational power is very limited due to the fact
that the black hole life-time is of the same order of the gate operation time.
As a consequence, it is impossible to retrieve its information, within the
life-time of a black hole, by externally coupling to the black hole qubits.
However, we show that, in principle, coupling to some of the internal degrees
of freedom allows acquiring knowledge about the micro-state. Still, due to the
trivial complexity of operations that can be performed, there is no time
advantage over the collection of Hawking radiation and subsequent decoding.Comment: 25+5 page
Black holes as collapsed polymers

We propose that a large Schwarzschild black hole (BH) is a bound state of
highly excited, long, closed strings at the Hagedorn temperature. The size of
the bound state is smaller than the string random-walk scale and determined
dynamically by the string attractive interactions. It is further proposed that
the effective free-energy density of the bound state should be expressed as a
function of its entropy density. For a macroscopic BH, the free-energy density
contains only linear and quadratic terms, in analogy with that of a collapsed
polymer when expressed as a function of the polymer concentration. Using the
effective free energy, we derive scaling relations for the entropy, energy and
size of the bound state and show that these agree with the scaling relations of
the BH; in particular, with the area law for the BH entropy. The area law
originates from the inverse scaling of the effective temperature with the
bound-state radius. We also find that the energy density of the bound state is
equal to its pressure.Comment: 20 page
Emergent horizon, Hawking radiation and chaos in the collapsed polymer
  model of a black hole

We have proposed that the interior of a macroscopic Schwarzschild black hole
(BH) consists of highly excited, long, closed, interacting strings and, as
such, can be modeled as a collapsed polymer. It was previously shown that the
scaling relations of the collapsed-polymer model agree with those of the BH.
The current paper further substantiates this proposal with an investigation
into some of its dynamical consequences. In particular, we show that the model
predicts, without relying on gravitational effects, an emergent horizon. We
further show that the horizon fluctuates quantum mechanically as it should and
that the strength of the fluctuations is inversely proportional to the BH
entropy. It is then demonstrated that the emission of Hawking radiation is
realized microscopically by the quantum-induced escape of small pieces of
string, with the rate of escape and the energy per emitted piece both
parametrically matching the Hawking temperature. We also show, using standard
methods from statistical mechanics and chaos theory, how our model accounts for
some other known properties of BHs. These include the accepted results for the
scrambling time and the viscosity-to-entropy ratio, which in our model apply
not only at the horizon but throughout the BH interior.Comment: 41 pages, 4 figures, added introductory material and figures. Belated
  updated version to match the published version. Results unchange
Nilpotent orbits in real symmetric pairs and stationary black holes

In the classification of stationary solutions in extended supergravities with
symmetric scalar manifolds, the nilpotent orbits of a real symmetric pair play
an important role. In this paper we discuss two approaches to determining the
nilpotent orbits of a real symmetric pair. We apply our methods to an explicit
example, and thereby classify the nilpotent orbits of SL_2(R)^4 acting on the
fourth tensor power of the natural 2-dimensional SL_2(R)-module. This makes it
possible to classify all stationary solutions of the so-called STU-supergravity
model.Comment: 31 pages; minor changes; one figure adde
Exotic RG Flows from Holography

Holographic RG flows are studied in an Einstein-dilaton theory with a general
potential. The superpotential formalism is utilized in order to characterize
and classify all solutions that are associated to asymptotically AdS
space-times. Such solutions correspond to holographic RG flows and are
characterized by their holographic $\beta$-functions. Novel solutions are found
that have exotic properties from a RG point-of view. Some have
$\beta$-functions that are defined patch-wise and lead to flows where the
$\beta$-function changes sign without the flow stopping. Others describe flows
that end in non-neighboring extrema in field space. Finally others describe
regular flows between two minima of the potential and correspond
holographically to flows driven by the VEV of an irrelevant operator in the UV
CFT.Comment: 104 pages, 37 figures. One appendix and one figure added. Matches
  published versio
Can Superconducting Cosmic Strings Piercing Seed Black Holes Generate
  Supermassive Black Holes in the Early Universe?

The discovery of a large number of supermassive black holes (SMBH) at
redshifts $z > 6$, when the Universe was only 900 million years old, raises the
question of how such massive compact objects could form in a cosmologically
short time interval. Each of the standard scenarios proposed, involving rapid
accretion of seed black holes or black hole mergers, faces severe theoretical
difficulties in explaining the short-time formation of supermassive objects. In
this work we propose an alternative scenario for the formation of SMBH in the
early Universe, in which energy transfer from superconducting cosmic strings
piercing small seed black holes is the main physical process leading to rapid
mass increase. As a toy model, the accretion rate of a seed black hole pierced
by two antipodal strings carrying constant current is considered. Using an
effective action approach, which phenomenologically incorporates a large class
of superconducting string models, we estimate the minimum current required to
form SMBH with masses of order $M = 2 \times 10^{9}M_{\odot}$ by $z = 7.085$.
This corresponds to the mass of the central black hole powering the quasar ULAS
J112001.48+064124.3 and is taken as a test case scenario for early-epoch SMBH
formation. For GUT scale strings, the required fractional increase in the
string energy density, due to the presence of the current, is of order
$10^{-7}$, so that their existence remains consistent with current
observational bounds on the string tension. In addition, we consider an
"exotic" scenario, in which an SMBH is generated when a small seed black hole
is pierced by a higher-dimensional $F-$string, predicted by string theory. We
find that both topological defect strings and fundamental strings are able to
carry currents large enough to generate early-epoch SMBH via our proposed
mechanism.Comment: 26 pages, no figures. Published versio
The Asymmetric CFT Landscape in D=4,6,8 with Extended Supersymmetry

We study asymmetric simple-current extensions of Gepner models in dimensions
$D=4,6,8$ with at least eight supercharges in the right-moving sector. The
models obtained in an extensive stochastic computer search belong to a small
number of different classes. These classes can be categorized as dimensional
reductions, asymmetric orbifolds with $(-1)^{F_L}$, extra gauge enhancement and
as coming from the super Higgs-effect. Models in the latter class are
particularly interesting, as they may correspond to non-geometric flux
compactifications.Comment: 37 page
Stationary $D=4$ Black Holes in Supergravity: The Issue of Real
  Nilpotent Orbits

The complete classification of the nilpotent orbits of ${\rm SO}(2,2)^2$ in
the representation ${\bf (2,2,2,2)}$, achieved in \cite{Dietrich:2016ojx}, is
applied to the study of multi-center, asymptotically flat, extremal black hole
solutions to the STU model. These real orbits provide an intrinsic
characterization of regular single-center solutions, which is invariant with
respect to the action of the global symmetry group ${\rm SO}(4,4)$, underlying
the stationary solutions of the model, and provide stringent regularity
constraints on multi-centered solutions. The known \emph{almost-BPS} and
\emph{composite non-BPS} solutions are revisited in this setting. We
systematically provide, for the relevant ${\rm SO}(2,2)^2$-nilpotent orbits of
the global Noether charge matrix, regular representatives thereof. This
analysis unveils a composition law of the orbits according to which those
containing regular multi-centered solutions can be obtained as combinations of
specific single-center orbits defining the constituent black holes. Some of the
${\rm SO}(2,2)^2$-orbits of the total Noether charge matrix are characterized
as "intrinsically singular" in that they cannot contain any regular solution.Comment: 104 pages, LaTeX source and 29 figure
On Heterotic Vacua with Fermionic Expectation Values

We study heterotic backgrounds with non-trivial $H$-flux and non-vanishing
expectation values of fermionic bilinears, often referred to as gaugino
condensates. The gaugini appear in the low energy action via the
gauge-invariant three-form bilinear $\Sigma_{MNP}={\rm
tr}\:\bar\chi\Gamma_{MNP}\chi$. For Calabi-Yau compactifications to four
dimensions, the gaugino condensate corresponds to an internal three-form
$\Sigma_{mnp}$ that must be a singlet of the holonomy group. This condition
does not hold anymore when an internal $H$-flux is turned on and ${\cal
O}(\alpha')$ effects are included. In this paper we study flux
compactifications to three and four-dimensions on $G$-structure manifolds. We
derive the generic conditions for supersymmetric solutions. We use
integrability conditions and Lichnerowicz type arguments to derive a set of
constraints whose solution, together with supersymmetry, is sufficient for
finding backgrounds with gaugino condensate.Comment: 44 pages, minor corrections, references adde
What is the Magnetic Weak Gravity Conjecture for Axions?

The electric Weak Gravity Conjecture demands that axions with large decay
constant $f$ couple to light instantons. The resulting large instantonic
corrections pose problems for natural inflation. We explore an alternative
argument based on the magnetic Weak Gravity Conjecture for axions, which we try
to make more precise. Roughly speaking, it demands that the minimally charged
string coupled to the dual 2-form-field exists in the effective theory. Most
naively, such large-$f$ strings curve space too much to exist as static
solutions, thus ruling out large-$f$ axions. More conservatively, one might
allow non-static string solutions to play the role of the required charged
objects. In this case, topological inflation would save the superplanckian
axion. Furthermore, a large-$f$ axion may appear in the low-energy effective
theory based on two subplanckian axions in the UV. The resulting effective
string is a composite object built from several fundamental strings and domain
walls. It may or may not satisfy the magnetic Weak Gravity Conjecture depending
on how strictly the latter is interpreted and on the cosmological dynamics of
this composite object, which remain to be fully understood. Finally, we recall
that large-field brane inflation is naively possible in the codimension-one
case. We show how string-theoretic back-reaction closes this apparent loophole
of large-$f$ (non-periodic) pseudo-axions.Comment: 29 pages, 7 figures; v2: Comment on topologically inflating monopoles
  added; v3: References adde
Field theoretical approach to gravitational waves

The aim of these notes is to give an accessible and self-contained
introduction to the theory of gravitational waves as the theory of a
relativistic symmetric tensor field in a Minkowski background spacetime. This
is the approach of a particle physicist: the graviton is identified with a
particular irreducible representation of the Poincar\'e group, corresponding to
vanishing mass and spin two. It is shown how to construct an action functional
giving the linear dynamics of gravitons, and how General Relativity can be
obtained from it. The Hamiltonian formulation of the linear theory is examined
in detail. We study the emission of gravitational waves and apply the results
to the simplest case of a binary Newtonian system.Comment: 47 pages, 3 figures, v2 matches the published versio