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Author 
Asenjo, F.A.; Erices, C.; Gomberoff, A.; Hojman, S.A.; Montecinos, A. 


Title 
Differential geometry approach to asymmetric transmission of light 
Type 


Year 
2017 
Publication 
Optics Express 
Abbreviated Journal 
Opt. Express 


Volume 
25 
Issue 
22 
Pages 
2640526416 


Keywords 



Abstract 
In the last ten years, the technology of differential geometry, ubiquitous in gravitational physics, has found its place in the field of optics. It has been successfully used in the design of optical metamaterials through a technique now known as “transformation optics.” This method, however, only applies for the particular class of metamaterials known as impedance matched, that is, materials whose electric permittivity is equal to their magnetic permeability. In that case, the material may be described by a spacetime metric. In the present work we will introduce a generalization of the geometric methods of transformation optics to situations in which the material is not impedance matched. In such situations, the material or more precisely, its constitutive tensorwill not be described by a metric only. We bring in a second tensor, with the local symmetries of the Weyl tensor, the “Wtensor.” In the geometric optics approximation we show how the properties of the Wtensor are related to the asymmetric transmission of the material. We apply this feature to the design of a particularly interesting set of asymmetric materials. These materials are birefringent when light rays approach the material in a given direction, but behave just like vacuum when the rays have the opposite direction with the appropriate polarization (or, in some cases, independently of the polarization). (C) 2017 Optical Society of America 


Address 
[Asenjo, Felipe A.; Gomberoff, Andres] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Av Diagonal Torres 2640, Santiago, Chile, Email: andres.gomberoff@uai.cl 


Corporate Author 

Thesis 



Publisher 
Optical Soc Amer 
Place of Publication 

Editor 



Language 
English 
Summary Language 

Original Title 



Series Editor 

Series Title 

Abbreviated Series Title 



Series Volume 

Series Issue 

Edition 



ISSN 
10944087 
ISBN 

Medium 



Area 

Expedition 

Conference 



Notes 
WOS:000413995000004 
Approved 



Call Number 
UAI @ eduardo.moreno @ 
Serial 
798 

Permanent link to this record 




Author 
Bunster, C.; Gomberoff, A. 


Title 
Gravitational domain walls and the dynamics of the gravitational constant G 
Type 


Year 
2017 
Publication 
Physical Review D 
Abbreviated Journal 
Phys. Rev. D 


Volume 
96 
Issue 
2 
Pages 
9 pp 


Keywords 



Abstract 
From the point of view of elementary particle physics the gravitational constant G is extraordinarily small. This has led to ask whether it could have decayed to its present value from an initial one commensurate with microscopical units. A mechanism that leads to such a decay is proposed herein. It is based on assuming that G may take different values within regions of the universe separated by a novel kind of domain wall, a “Gwall”. The idea is implemented by introducing a gauge potential A, and its conjugate D, which determines the value of G as an integration constant rather than a fundamental constant. The value of G jumps when one goes through a Gwall. The procedure extends one previously developed for the cosmological constant, but the generalization is far from straightforward: (i) The intrinsic geometry of a Gwall is not the same as seen from its two sides, because the second law of black hole thermodynamics mandates that the jump in G must cause a discontinuity in the scale of length. (ii) The size of the decay step in G is controlled by a function G(D) which may be chosen so as to diminish the value of G towards the asymptote G = 0, without fine tuning. It is shown that: (i) The dynamics of the gravitational field with G treated as a dynamical variable, coupled to Gwalls and matter, follows from an action principle, which is given. (ii) A particle that impinges on a Gwall may be refracted or reflected. (iii) The various forces between two particles change when a Gwall is inserted in between them. (iv) Gwalls may be nucleated trough tunneling and thermal effects. The semiclassical probabilities are evaluated. (v) If the action principle is constructed properly, the entropy of a black hole increases when the value of the gravitational constant is changed through the absorption of a Gwall by the hole. 


Address 
[Bunster, Claudio; Gomberoff, Andres] Ctr Estudios Cient, Casilla 1469, Valdivia, Chile, Email: bunster@cecs.cl; 


Corporate Author 

Thesis 



Publisher 
Amer Physical Soc 
Place of Publication 

Editor 



Language 
English 
Summary Language 

Original Title 



Series Editor 

Series Title 

Abbreviated Series Title 



Series Volume 

Series Issue 

Edition 



ISSN 
24700010 
ISBN 

Medium 



Area 

Expedition 

Conference 



Notes 
WOS:000405925400004 
Approved 



Call Number 
UAI @ eduardo.moreno @ 
Serial 
747 

Permanent link to this record 




Author 
Bunster, C.; Gomberoff, A.; Perez, A. 


Title 
BondiMetznerSachs invariance and electricmagnetic duality 
Type 


Year 
2020 
Publication 
Physical Review D 
Abbreviated Journal 
Phys. Rev. D 


Volume 
101 
Issue 
4 
Pages 
15 pp 


Keywords 



Abstract 
We exhibit a Hamiltonian formulation, both for electromagnetism and gravitation, in which it is not required that the Bondi “news” vanish but only that the incoming news be equal to the outgoing ones. This requirement is implemented by defining the fields on a twosheeted hyperbolic surface, which we term “the hourglass.” It is a spacelike deformation of the complete light cone. On it, one approaches asymptotically (null) past and future infinity while remaining at a fixed (hyperbolic) time, by going to large spatial distances on its two sheets. The Hamiltonian formulation andin particulara conserved angular momentum, can only be constructed if one brings in both the electric and magnetic BondiMetznerSachs (BMS) charges together with their canonically conjugate “memories.” This reveals a close interplay between the BMS and electricmagnetic duality symmetries. 


Address 
[Bunster, Claudio; Gomberoff, Andres; Perez, Alfredo] Ctr Estudios Cien CECs, Casilla 1469, Valdivia, Chile 


Corporate Author 

Thesis 



Publisher 
Amer Physical Soc 
Place of Publication 

Editor 



Language 
English 
Summary Language 

Original Title 



Series Editor 

Series Title 

Abbreviated Series Title 



Series Volume 

Series Issue 

Edition 



ISSN 
24700010 
ISBN 

Medium 



Area 

Expedition 

Conference 



Notes 
WOS:000511199300005 
Approved 



Call Number 
UAI @ eduardo.moreno @ 
Serial 
1098 

Permanent link to this record 




Author 
Canfora, F.; Gomberoff, A.; Oh, S.H.; Rojas, F.; SalgadoRebolledo, P. 


Title 
Meronic EinsteinYangMills black hole in 5D and gravitational spin from isospin effect 
Type 


Year 
2019 
Publication 
Journal Of High Energy Physics 
Abbreviated Journal 
J. High Energy Phys. 


Volume 

Issue 
6 
Pages 
32 pp 


Keywords 
Black Holes; Field Theories in Higher Dimensions; Gauge Symmetry; Solitons Monopoles and Instantons 


Abstract 
We construct an analytic black hole solution in SU(2) EinsteinYangMills theory in five dimensions supporting a Meron field. The gauge field is proportional to a pure gauge and has a nontrivial topological charge. The wouldbe singularity at the Meron core gets shielded from the exterior by the black hole horizon. The metric has only one integration constant, namely, its ADM mass, which is shown to be finite once an appropriate boundary term is added to the action. The thermodynamics is also worked out, and a firstorder phase transition, similar to the one occurring in the ReissnerNordstrom case is identified. We also show that the solution produces a spin from isospin effect, i.e., even though the theory is constructed out of bosons only, the combined system of a scalar field and this background may become fermionic. More specifically, we study scalar excitations in this purely bosonic background and find that the system describes fermionic degrees of freedom at spatial infinity. Finally, for the asymptotically AdS(5) case, we study its consequences in the context of the AdS/CFT correspondence. 


Address 
[Canfora, Fabrizio; Gomberoff, Andres] Ctr Estudios Cient, Casilla 1469, Valdivia, Chile, Email: canfora@cecs.cl; 


Corporate Author 

Thesis 



Publisher 
Springer 
Place of Publication 

Editor 



Language 
English 
Summary Language 

Original Title 



Series Editor 

Series Title 

Abbreviated Series Title 



Series Volume 

Series Issue 

Edition 



ISSN 
10298479 
ISBN 

Medium 



Area 

Expedition 

Conference 



Notes 
WOS:000472210200001 
Approved 



Call Number 
UAI @ eduardo.moreno @ 
Serial 
1024 

Permanent link to this record 