A
bstract
Celestial holography promisingly reformulates the scattering amplitude holographically in terms of celestial conformal field theory living at null infinity. Recently, an ...infinite-dimensional symmetry algebra was discovered in Einstein-Yang-Mills theory. The starting point in the derivation is the celestial OPE of two soft currents, and the key ingredient is the summation of
SL
2
ℝ
¯
descendants in OPE. In this paper, we consider the supersymmetric Einstein-Yang-Mills theory and obtain the supersymmetric extension of the holographic symmetry algebra. Furthermore, we derive infinitely many Ward identities associated with the infinite soft currents which generate the holographic symmetry algebra. This is realized by considering the OPE between a soft symmetry current and a hard operator, and then summing over its
SL
2
ℝ
¯
descendants. These Ward identities reproduce the known Ward identities corresponding to the leading, sub-leading, and sub-sub-leading soft graviton theorems as well as the leading and sub-leading soft gluon theorems. By performing shadow transformations, we also obtain infinitely many shadow Ward identities, including the stress tensor Ward identities for sub-leading soft graviton. Finally, we use our procedure to discuss the corrections to Ward identities in effective field theory (EFT), and reproduce the corrections to soft theorems at sub-sub-leading order for graviton and sub-leading order for photon. For this aim, we derive general formulae for the celestial OPE and its corresponding Ward identities arising from a cubic interaction of three spinning massless particles. Our formalism thus provides a unified framework for understanding the Ward identities in celestial conformal field theory, or equivalently the soft theorems in scattering amplitude.
We present PrVM, a framework for scheduling real-time VMs on multicore hardware. It addresses the intersection of the following problems: probabilistic real-time scheduling, VM scheduling, and full ...virtualization. Though each of these problems have been studied, their intersection - motivated by the need to consolidate multiple real-time software stacks, whose applications can be defined via probabilistic timing properties, onto a single embedded platform - is empty. PrVM uses a probabilistic model and timeliness optimality criterion. PrVM schedules VMs as server-like processes, computes time budgets using probabilistic methods, and aggregates task time budgets into VM time budgets. Experimental evaluations, using simulations and a concrete implementation, confirm the framework's effectiveness for synthetic benchmarks and multimedia applications.
A
bstract
We extend the localization calculation of the 3D Chern-Simons partition func- tion over Seifert manifolds to an analogous calculation in five dimensions. We construct a twisted version of
N
...= 1 supersymmetric Yang-Mills theory defined on a circle bundle over a four dimensional symplectic manifold. The notion of contact geometry plays a crucial role in the construction and we suggest a generalization of the instanton equations to five- dimensional contact manifolds. Our main result is a calculation of the full perturbative partition function on
S
5
for the twisted supersymmetric Yang-Mills theory with different Chern-Simons couplings. The final answer is given in terms of a matrix model. Our construction admits generalizations to higher dimensional contact manifolds. This work is inspired by the work of Baulieu-Losev-Nekrasov from the mid 90’s, and in a way it is covariantization of their ideas for a contact manifold.
A
bstract
In this third paper of a series dedicated to a dispersive treatment of the hadronic light-by-light (HLbL) tensor, we derive a partial-wave formulation for two-pion intermediate states in ...the HLbL contribution to the anomalous magnetic moment of the muon (
g
− 2)
μ
, including a detailed discussion of the unitarity relation for arbitrary partial waves. We show that obtaining a final expression free from unphysical helicity partial waves is a subtle issue, which we thoroughly clarify. As a by-product, we obtain a set of sum rules that could be used to constrain future calculations of
γ
∗
γ
∗
→
ππ
. We validate the formalism extensively using the pion-box contribution, defined by two-pion intermediate states with a pion-pole left-hand cut, and demonstrate how the full known result is reproduced when resumming the partial waves. Using dispersive fits to high-statistics data for the pion vector form factor, we provide an evaluation of the full pion box,
a
μ
π
− box
= − 15.9(2) × 10
− 11
. As an application of the partial-wave formalism, we present a first calculation of
ππ
-rescattering effects in HLbL scattering, with
γ
∗
γ
∗
→
ππ
helicity partial waves constructed dispersively using
ππ
phase shifts derived from the inverse-amplitude method. In this way, the isospin-0 part of our calculation can be interpreted as the contribution of the
f
0
(500) to HLbL scattering in (
g
− 2)
μ
. We argue that the contribution due to charged-pion rescattering implements corrections related to the corresponding pion polarizability and show that these are moderate. Our final result for the sum of pion-box contribution and its
S
-wave rescattering corrections reads
a
μ
π
‐ box
+
a
μ
,
J
= 0
ππ
,
π
‐ pole LHC
= − 24(1) × 10
− 11
.
Webs of W-algebras Procházka, Tomáš; Rapčák, Miroslav
The journal of high energy physics,
11/2018, Letnik:
2018, Številka:
11
Journal Article
Recenzirano
Odprti dostop
A
bstract
We associate vertex operator algebras to (
p, q
)-webs of interfaces in the topologically twisted
N
=
4
super Yang-Mills theory. Y-algebras associated to trivalent junctions are identified ...with truncations of
W
1+∞
algebra. Starting with Y-algebras as atomic elements, we describe gluing of Y-algebras analogous to that of the topological vertex. At the level of characters, the construction matches the one of counting D0-D2-D4 bound states in toric Calabi-Yau threefolds. For some configurations of interfaces, we propose a BRST construction of the algebras and check in examples that both constructions agree. We define generalizations of
W
1+∞
algebra and identify a large class of glued algebras with their truncations. The gluing construction sheds new light on the structure of vertex operator algebras conventionally constructed by BRST reductions or coset constructions and provides us with a way to construct new algebras. Many well-known vertex operator algebras, such as U(
N
)
k
affine Lie algebra,
N
=
2
superconformal algebra,
N
=
2
super-
W
∞
, Bershadsky-Polyakov
W
3
2
, cosets and Drinfeld-Sokolov reductions of unitary groups can be obtained as special cases of this construction.
A
bstract
We propose a holographic entanglement entropy prescription for general states and regions in two models of holography beyond AdS/CFT known as flat
3
/BMSFT and (W)AdS
3
/WCFT. Flat
3
/BMSFT ...is a candidate of holography for asymptotically flat three- dimensional spacetimes, while (W)AdS
3
/WCFT is relevant in the study of black holes in the real world. In particular, the boundary theories are examples of quantum field theories that feature an infinite dimensional symmetry group but break Lorentz invariance. Our holographic entanglement entropy proposal is given by the area of a
swing surface
that consists of
ropes
, which are null geodesics emanating from the entangling surface at the boundary, and a
bench
, which is a spacelike geodesic connecting the ropes. The proposal is supported by an extension of the Lewkowycz-Maldacena argument, reproduces previous results based on the Rindler method, and satisfies the first law of entanglement entropy.
A
bstract
We revisit the perturbative expansion at high temperature and investigate its convergence by inspecting the renormalisation scale dependence of the effective potential. Although at zero ...temperature the renormalisation group improved effective potential is scale independent at one-loop, we show how this breaks down at high temperature, due to the misalignment of loop and coupling expansions. Following this, we show how one can recover renormalisation scale independence at high temperature, and that it requires computations at two-loop order. We demonstrate how this resolves some of the huge theoretical uncertainties in the gravitational wave signal of first-order phase transitions, though uncertainties remain stemming from the computation of the bubble nucleation rate.
We describe an actionable research approach for addressing current challenges to theoretical advancement labeled theory elaboration. Theory elaboration is the process of conceptualizing and executing ...empirical research using preexisting conceptual ideas or a preliminary model as a basis for developing new theoretical insights by contrasting, specifying, or structuring theoretical constructs and relations to account for and explain empirical observations. We identify and describe seven specific tactics for conducting a theory elaboration study: horizontal contrasting, vertical contrasting, new construct specification, construct splitting, structuring specific relations, structuring sequence relations, and structuring recursive relations. We also link each tactic with different types of theory advancements. In addition, we provide a sequential decision-making process for deciding whether to adopt a theory elaboration approach given a particular research domain and context. Finally, we identify research domains and specific topics in organizational behavior, human resource management, strategic management, and entrepreneurship for which theory elaboration is likely to be most effective as a means to make theoretical advancements.
A
bstract
We study black hole linear perturbation theory in a four-dimensional Schwarzschild (anti) de Sitter background. When dealing with a
positive
cosmological constant, the corresponding ...spectral problem is solved systematically via the Nekrasov-Shatashvili functions or, equivalently, classical Virasoro conformal blocks. However, this approach can be more complicated to implement for certain perturbations if the cosmological constant is
negative
. For these cases, we propose an alternative method to set up perturbation theory for both small and large black holes in an analytical manner. Our analysis reveals a new underlying recursive structure that involves multiple polylogarithms. We focus on gravitational, electromagnetic, and conformally coupled scalar perturbations subject to Dirichlet and Robin boundary conditions. The low-lying modes of the scalar sector of gravitational perturbations and its hydrodynamic limit are studied in detail.
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