2,028 research outputs found
On the relation between local and geometric Lagrangians for higher spins
Equations of motion for free higher-spin gauge fields of any symmetry can be
formulated in terms of linearised curvatures. On the other hand, gauge
invariance alone does not fix the form of the corresponding actions which, in
addition, either contain higher derivatives or involve inverse powers of the
d'Alembertian operator, thus introducing possible subtleties in degrees of
freedom count. We suggest a path to avoid ambiguities, starting from local,
unconstrained Lagrangians previously proposed, and integrating out the
auxiliary fields from the functional integral, thus generating a unique
non-local theory expressed in terms of curvatures.Comment: 14 pages. Contribution to the proceedings of the 1st Mediterranean
Conference on Classical and Quantum Gravity, Kolymbary (Crete, Greece)
September 14-18 200
Multimetric Supergravities
Making use of integral forms and superfield techniques we propose
supersymmetric extensions of the multimetric gravity Lagrangians in dimensions
one, two, three and four. The supersymmetric interaction potential covariantly
deforms the bosonic one, producing in particular suitable super-symmetric
polynomials generated by the Berezinian. As an additional application of our
formalism we construct supersymmetric multi-Maxwell theories in dimensions
three and four.Comment: 37 pages, Latex2e, no figure
Confined two-dimensional fermions at finite density
We introduce the chemical potential in a system of two-dimensional massless
fermions, confined to a finite region, by imposing twisted boundary conditions
in the Euclidean time direction. We explore in this simple model the
application of functional techniques which could be used in more complicated
situations.Comment: 15 pages, LaTe
Massless fermions in a bag at finite density and temperature
We introduce the chemical potential in a system of massless fermions in a bag
by impossing boundary conditions in the Euclidean time direction. We express
the fermionic mean number in terms of a functional trace involving the Green's
function of the boundary value problem, which we study analytically. Numerical
evaluations are made, and an application to a simple hadron model is discussed.Comment: 14 pages, 3 figures, RevTe
Finite density and temperature in hybrid bag models
We introduce the chemical potential in a system of two-flavored massless
fermions in a chiral bag by imposing boundary conditions in the Euclidean time
direction. We express the fermionic mean number in terms of a functional trace
involving the Green function of the boundary value problem, which is studied
analytically. Numerical evaluations for the fermionic number are presented.Comment: 19 pages, 4 figure
Towards an In-depth Understanding of Deep Packet Inspection Using a Suite of Industrial Control Systems Protocol Packets
Industrial control systems (ICS) are increasingly at risk and vulnerable to internal and external threats. These systems are integral part of our nation’s critical infrastructures. Consequently, a successful cyberattack on one of these could present disastrous consequences to human life and property as well. It is imperative that cybersecurity professionals gain a good understanding of these systems particularly in the area of communication protocols. Traditional Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are made to encapsulate some of these ICS protocols which may enable malicious payload to get through the network firewall and thus, gain entry into the network. This paper describes technical details on various ICS protocols and a suite of ICS protocol packets for the purpose of providing digital forensic materials for laboratory exercises toward a better understanding of the inner workings of ICS communications. Further, these artifacts can be useful in devising deep packet inspection (DPI) strategies that can be implemented in network firewalls, in expanding challenge materials for cyber competitions, and in attribution, vulnerability assessment, and penetration testing research in ICS security. We also present software tools that are available for free download on the Internet that could be used to generate simulated ICS and Supervisory Control and Data Acquisition (SCADA) communication packets for research and pedagogical purposes. Finally, we conclude the paper by presenting possible research avenues that can be pursued as extensions to this seminal work on ICS security. Prominent among these possible extensions is the expansion of the ICS packet suite to include those protocols in the wireless domain such as Wi-Fi (802.11), Bluetooth, Zigbee, and other protocols that utilizes proprietary Radio Frequency
Maxwell-like Lagrangians for higher spins
We show how implementing invariance under divergence-free gauge
transformations leads to a remarkably simple Lagrangian description of massless
bosons of any spin. Our construction covers both flat and (A)dS backgrounds and
extends to tensors of arbitrary mixed-symmetry type. Irreducible and traceless
fields produce single-particle actions, while whenever trace constraints can be
dispensed with the resulting Lagrangians display the same reducible,
multi-particle spectra as those emerging from the tensionless limit of free
open-string field theory. For all explored options the corresponding kinetic
operators take essentially the same form as in the spin-one, Maxwell case.Comment: 77 pages, revised version. Erroneous interpretation and proof of the
gauge-fixing procedure for mixed-symmetry fields corrected. As a consequence,
the mixed-symmetry, one-particle Lagrangians are to be complemented with
conditions on the divergences of the fields; all other conclusions unchanged.
Additional minor changes including references added. To appear in JHE
Towards an In-depth Understanding of Deep Packet Inspection Using a Suite of Industrial Control Systems Protocol Packets
Industrial control systems (ICS) are increasingly at risk and vulnerable to internal and external threats. These systems are integral part of our nation’s critical infrastructures. Consequently, a successful cyberattack on one of these could present disastrous consequences to human life and property as well. It is imperative that cybersecurity professionals gain a good understanding of these systems particularly in the area of communication protocols. Traditional Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are made to encapsulate some of these ICS protocols which may enable malicious payload to get through the network firewall and thus, gain entry into the network. This paper describes technical details on various ICS protocols and a suite of ICS protocol packets for the purpose of providing digital forensic materials for laboratory exercises toward a better understanding of the inner workings of ICS communications. Further, these artifacts can be useful in devising deep packet inspection (DPI) strategies that can be implemented in network firewalls, in expanding challenge materials for cyber competitions, and in attribution, vulnerability assessment, and penetration testing research in ICS security
Effective action in a higher-spin background
We consider a free massless scalar field coupled to an infinite tower of
background higher-spin gauge fields via minimal coupling to the traceless
conserved currents. The set of Abelian gauge transformations is deformed to the
non-Abelian group of unitary operators acting on the scalar field. The gauge
invariant effective action is computed perturbatively in the external fields.
The structure of the various (divergent or finite) terms is determined. In
particular, the quadratic part of the logarithmically divergent (or of the
finite) term is expressed in terms of curvatures and related to conformal
higher-spin gravity. The generalized higher-spin Weyl anomalies are also
determined. The relation with the theory of interacting higher-spin gauge
fields on anti de Sitter spacetime via the holographic correspondence is
discussed.Comment: 40 pages, Some errors and typos corrected, Version published in JHE
Asymptotic symmetries and charges at null infinity: from low to high spins
Weinberg's celebrated factorisation theorem holds for soft quanta of
arbitrary integer spin. The same result, for spin one and two, has been
rederived assuming that the infinite-dimensional asymptotic symmetry group of
Maxwell's equations and of asymptotically flat spaces leave the S-matrix
invariant. For higher spins, on the other hand, no such infinite-dimensional
asymptotic symmetries were known and, correspondingly, no a priori derivation
of Weinberg's theorem could be conjectured. In this contribution we review the
identification of higher-spin supertranslations and superrotations in as
well as their connection to Weinberg's result. While the procedure we follow
can be shown to be consistent in any , no infinite-dimensional enhancement
of the asymptotic symmetry group emerges from it in , thus leaving a
number of questions unanswered.Comment: 11 pages. Contribution to the proceedings of Quarks-2018, XXth
International Seminar on High Energy Physics; Valday, Russia, 27 May - 2 June
201
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