A
bstract
In this work, a non-Gaussian cMERA tensor network for interacting quantum field theories (icMERA) is presented. This consists of a continuous tensor network circuit in which the generator ...of the entanglement renormalization of the wavefunction is nonperturbatively extended with nonquadratic variational terms. The icMERA circuit nonperturbatively implements a set of scale dependent nonlinear transformations on the fields of the theory, which suppose a generalization of the scale dependent linear transformations induced by the Gaussian cMERA circuit. Here we present these transformations for the case of self-interacting scalar and fermionic field theories. Finally, the icMERA tensor network is fully optimized for the
λϕ
4
theory in (1 + 1) dimensions. This allows us to evaluate, nonperturbatively, the connected parts of the two- and four-point correlation functions. Our results show that icMERA wavefunctionals encode proper non-Gaussian correlations of the theory, thus providing a new variational tool to study phenomena related with strongly interacting field theories.
A general method to build the entanglement renormalization (cMERA) for interacting quantum field theories is presented. We improve upon the well-known Gaussian formalism used in free theories through ...a class of variational non-Gaussian wave functionals for which expectation values of local operators can be efficiently calculated analytically and in a closed form. The method consists of a series of scale-dependent nonlinear canonical transformations on the fields of the theory under consideration. Here, the λϕ4 and the sine-Gordon scalar theories are used to illustrate how nonperturbative effects far beyond the Gaussian approximation are obtained by considering the energy functional and the correlation functions of the theory.
Duality orbits of non-geometric fluxes Dibitetto, G.; Fernández-Melgarejo, J.J.; Marqués, D. ...
Fortschritte der Physik,
November 2012, Letnik:
60, Številka:
11-12
Journal Article
Recenzirano
Odprti dostop
Compactifications in duality covariant constructions such as generalised geometry and double field theory have proven to be suitable frameworks to reproduce gauged supergravities containing ...non‐geometric fluxes. However, it is a priori unclear whether these approaches only provide a reformulation of old results, or also contain new physics. To address this question, we classify the T‐ and U‐duality orbits of gaugings of (half‐)maximal supergravities in dimensions seven and higher. It turns out that all orbits have a geometric supergravity origin in the maximal case, while there are non‐geometric orbits in the half‐maximal case. We show how the latter are obtained from compactifications of double field theory.
The Odd story of α′-corrections Baron, Walter H.; Fernández-Melgarejo, José J.; Marqués, Diego ...
The journal of high energy physics,
04/2017, Letnik:
2017, Številka:
4
Journal Article
Recenzirano
Odprti dostop
A
bstract
The
α
′-deformed frame-like Double Field Theory (DFT) is a T-duality and gauge invariant extension of DFT in which generalized Green-Schwarz transformations provide a gauge principle that ...fixes the higher-derivative corrections. It includes all the first order
α
′-corrections of the bosonic and heterotic string low energy effective actions and of the Hohm-Siegel-Zwiebach
α
′-geometry. Here we gauge this theory and parameterize it in terms of a frame, a two-form, a dilaton, gauge vectors and scalar fields. This leads to a unified framework that extends the previous construction by including all duality constrained interactions in generic (gauged/super)gravity effective field theories in arbitrary number of dimensions, to first order in
α
′.
Weaving the exotic web Fernández-Melgarejo, José J.; Kimura, Tetsuji; Sakatani, Yuho
The journal of high energy physics,
09/2018, Letnik:
2018, Številka:
9
Journal Article
Recenzirano
Odprti dostop
A
bstract
String and M-theory contain a family of branes forming
U
-duality multiplets. In particular, standard branes with codimension higher than or equal to two, can be explicitly found as ...supergravity solutions. However, whether domain-wall branes and space-filling branes can be found as supergravity solutions is still unclear. In this paper, we firstly provide a full list of exotic branes in type II string theory or M-theory compactified to three or higher dimensions. We show how to systematically obtain backgrounds of exotic domain-wall branes and space-filling branes as solutions of the double field theory or the exceptional field theory. Such solutions explicitly depend on the winding coordinates and cannot be given as solutions of the conventional supergravity theories. However, as the domain-wall solutions depend linearly on the winding coordinates, we describe them as solutions of deformed supergravities such as the Romans massive IIA supergravity or lower-dimensional gauged supergravities. We establish explicit relations among the domain-wall branes, the mixed-symmetry potentials, the locally non-geometric fluxes, and deformed supergravities.
T -folds from Yang-Baxter deformations Fernández-Melgarejo, José J.; Sakamoto, Jun-ichi; Sakatani, Yuho ...
The journal of high energy physics,
12/2017, Letnik:
2017, Številka:
12
Journal Article
Recenzirano
Odprti dostop
A
bstract
Yang-Baxter (YB) deformations of type IIB string theory have been well studied from the viewpoint of classical integrability. Most of the works, however, are focused upon the local ...structure of the deformed geometries and the global structure still remains unclear. In this work, we reveal a non-geometric aspect of YB-deformed backgrounds as
T
-fold by explicitly showing the associated O(
D
,
D
;
ℤ
)
T
-duality monodromy. In particular, the appearance of an extra vector field in the generalized supergravity equations (GSE) leads to the non-geometric
Q
-flux. In addition, we study a particular solution of GSE that is obtained by a non-Abelian
T
-duality but cannot be expressed as a homogeneous YB deformation, and show that it can also be regarded as a
T
-fold. This result indicates that solutions of GSE should be non-geometric quite in general beyond the YB deformation.
We revisit Weyl invariance string theories in generalized supergravity backgrounds. A possible counterterm was constructed in a work by Sakamoto, Sakatani, and Yoshida, but it seems to be a point of ...controversy in some literatures whether or not it is nonlocal. To settle down this issue, we show that the counterterm may be local and exactly cancels out the one-loop trace anomaly in generalized supergravity backgrounds.
A
bstract
In this work we provide a method to study the entanglement entropy for non-Gaussian states that minimize the energy functional of interacting quantum field theories at arbitrary coupling. ...To this end, we build a class of non-Gaussian variational trial wavefunctionals with the help of exact nonlinear canonical transformations. The calculability
bonanza
shown by these variational
ansatze
allows us to compute the entanglement entropy using the prescription for the ground state of free theories. In free theories, the entanglement entropy is determined by the two-point correlation functions. For the interacting case, we show that these two-point correlators can be replaced by their nonperturbatively corrected counterparts. Upon giving some general formulae for general interacting models we calculate the entanglement entropy of half space and compact regions for the
ϕ
4
scalar field theory in 2D. Finally, we analyze the rôle played by higher order correlators in our results and show that strong subadditivity is satisfied.
The large N limit of icMERA and holography Fernández-Melgarejo, José J.; Molina-Vilaplana, Javier
The journal of high energy physics,
04/2022, Letnik:
2022, Številka:
4
Journal Article
Recenzirano
Odprti dostop
A
bstract
In this work, we compute the entanglement entropy in continuous icMERA tensor networks for large
N
models at strong coupling. Our results show that the 1
/N
quantum corrections to the ...Fisher information metric (interpreted as a local bond dimension of the tensor network) in an icMERA circuit, are related to quantum corrections to the minimal area surface in the Ryu-Takayanagi formula. Upon picking two different non-Gaussian entanglers to build the icMERA circuit, the results for the entanglement entropy only differ at subleading orders in 1
/G
N
, i.e., at the structure of the quantum corrections in the bulk. The fact that the large
N
part of the entropy can be always related to the leading area term of the holographic calculation is very suggestive. These results, constitute the first tensor network calculations at large
N
and strong coupling simultaneously, pushing the field of tensor network descriptions of the emergence of dual spacetime geometries from the structure of entanglement in quantum field theory.
On the Entanglement Entropy in Gaussian cMERA Fernández‐Melgarejo, J. J.; Molina‐Vilaplana, J.
Fortschritte der Physik,
December 2021, 2021-12-00, 20211201, Letnik:
69, Številka:
11-12
Journal Article
Recenzirano
Odprti dostop
The continuous Multi Scale Entanglement Renormalization Anstaz (cMERA) consists of a variational method which carries out a real space renormalization scheme on the wavefunctionals of quantum field ...theories. In this work we calculate the entanglement entropy of the half space for a free scalar theory through a Gaussian cMERA circuit. We obtain the correct entropy written in terms of the optimized cMERA variational parameter, the local density of disentanglers. Accordingly, using the entanglement entropy production per unit scale, we study local areas in the bulk of the tensor network in terms of the differential entanglement generated along the cMERA flow. This result spurs us to establish an explicit relation between the cMERA variational parameter and the radial component of a dual AdS geometry through the Ryu‐Takayanagi formula. Finally, we argue that the entanglement entropy for the half space can be written as an integral along the renormalization scale whose measure is given by the Fisher information metric of the cMERA circuit. Consequently, a straightforward relation between AdS geometry and the Fisher information metric is also established.
The continuous Multi Scale Entanglement Renormalization Anstaz (cMERA) consists of a variational method which carries out a real space renormalization scheme on the wavefunctionals of quantum field theories. In this work the entanglement entropy of the half space for a free scalar theory through a Gaussian cMERA circuit is calculated. The authors obtain the correct entropy written in terms of the optimized cMERA variational parameter, the local density of disentanglers. Accordingly, using the entanglement entropy production per unit scale, local areas in the bulk of the tensor network are studied in terms of the differential entanglement generated along the cMERA flow. This result spurs to establish an explicit relation between the cMERA variational parameter and the radial component of a dual AdS geometry through the Ryu‐Takayanagi formula. Finally, it will be argued that the entanglement entropy for the half space can be written as an integral along the renormalization scale whose measure is given by the Fisher information metric of the cMERA circuit. Consequently, a straightforward relation between AdS geometry and the Fisher information metric is also established.
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