scholarly journals Erratum to: T duality and Wald entropy formula in the Heterotic Superstring effective action at first-order in α′

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Zachary Elgood ◽  
Tomás Ortín
Keyword(s):  
Effective Action ◽  
First Order ◽  
Entropy Formula

A correction to this paper has been published: https://doi.org/10.1007/JHEP10(2020)097

scholarly journals The first law and Wald entropy formula of heterotic stringy black holes at first order in α′

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Zachary Elgood ◽  
Tomás Ortín ◽  
David Pereñíguez
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Effective Action ◽  
Differential Forms ◽  
Momentum Maps ◽  
First Order ◽  
Entropy Formula ◽  
Lie Derivatives

Abstract We derive the first law of black hole mechanics in the context of the Heterotic Superstring effective action to first order in α′ using Wald’s formalism. We carefully take into account all the symmetries of the theory and, as a result, we obtain a manifestly gauge- and Lorentz-invariant entropy formula in which all the terms can be computed explicitly. An entropy formula with these properties allows unambiguous calculations of macroscopic black-hole entropies to first order in α′ that can be reliably used in a comparison with the microscopic ones. Such a formula was still lacking in the literature.In the proof we use momentum maps to define covariant variations and Lie derivatives and restricted generalized zeroth laws which state the closedness of certain differential forms on the bifurcation sphere and imply the constancy of the associated potentials on it.We study the relation between our entropy formula and other formulae that have been used in the literature.

scholarly journals T duality and Wald entropy formula in the Heterotic Superstring effective action at first-order in α′

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Zachary Elgood ◽  
Tomás Ortín
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Effective Action ◽  
Extremal Black Hole ◽  
Slope Parameter ◽  
First Order ◽  
Duality Transformations ◽  
Entropy Formula ◽  
Reduced Action ◽  
Black Hole Solutions

Abstract We consider the compactification on a circle of the Heterotic Superstring effective action to first order in the Regge slope parameter α′ and re-derive the α′-corrected Buscher rules first found in ref. [42], proving the T duality invariance of the dimensionally-reduced action to that order in α′. We use Iyer and Wald’s prescription to derive an entropy formula that can be applied to black-hole solutions which can be obtained by a single non-trivial compactification on a circle and discuss its invariance under the α′-corrected T duality transformations. This formula has been successfully applied to α′-corrected 4-dimensional non-extremal Reissner-Nordström black holes in ref. [21] and we apply it here to a heterotic version of the Strominger-Vafa 5-dimensional extremal black hole.

scholarly journals O(n, n) invariance and Wald entropy formula in the Heterotic Superstring effective action at first order in α′

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Tomás Ortín
Keyword(s):  
Black Holes ◽  
Effective Action ◽  
Invariant Form ◽  
First Order ◽  
Entropy Formula ◽  
Reduced Action

Abstract We perform the toroidal compactification of the full Bergshoeff-de Roo version of the Heterotic Superstring effective action to first order in α′. The dimensionally-reduced action is given in a manifestly-O(n, n)-invariant form which we use to derive a manifestly-O(n, n)-invariant Wald entropy formula which we then use to compute the entropy of α′-corrected, 4-dimensional, 4-charge, static, extremal, supersymmetric black holes.

scholarly journals GRAVITY ON NONCOMMUTATIVE D-BRANES

2003 ◽  
Vol 18 (07) ◽  
pp. 1051-1066 ◽  
Author(s):  
F. ARDALAN ◽  
H. ARFAEI ◽  
M. R. GAROUSI ◽  
A. GHODSI
Keyword(s):  
String Theory ◽  
Effective Action ◽  
Low Energy ◽  
Bosonic String ◽  
First Order ◽  
Energy Scattering ◽  
Bosonic String Theory ◽  
Brane Action

The effective action for the low energy scattering of two gravitons with a D-brane in the presence of a constant antisymmetric B field in bosonic string theory is calculated and the modification to the standard D-brane action to first order in α′ is obtained.

Calculation of the thermodynamic quantities of perovskite metal organics DMAKCr and perovskite HyFe close to the weakly first-order relaxor-like structural transformation using the mean field theory

2019 ◽  
Vol 33 (11) ◽  
pp. 1950103 ◽  
Author(s):  
H. Yurtseven ◽  
Ö. Tarı
Keyword(s):  
Field Theory ◽  
Field Model ◽  
Mean Field Theory ◽  
Mean Field ◽  
Excess Heat Capacity ◽  
Mean Field Model ◽  
First Order ◽  
Entropy Formula ◽  
Inverse Susceptibility ◽  
The Mean

Weakly first-order or nearly second-order phase transitions occurring in metal–organic frameworks (MOFs), particularly in DMAKCr and perovskite HyFe, are studied under the mean field model by using the observed data from the literature. In this work, mainly thermal and magnetic properties among various physical properties which have been reported in the literature for those MOFs are studied by the mean field theory. By expanding the free energy in terms of the magnetization (order parameter), the excess heat capacity ([Formula: see text]C[Formula: see text]) and entropy ([Formula: see text]S), latent heat (L), magnetization (M) and the inverse susceptibility ([Formula: see text]) are calculated as a function of temperature close to the weakly first-order phase transition within the Landau phenomenological model which is fitted to the experimental data from the literature for C[Formula: see text] (DMAKCr and perovskite HyFe) and for magnetization M (HyFe). Our predictions of the excess heat capacity ([Formula: see text]C[Formula: see text]) and entropy ([Formula: see text]S) agree below T[Formula: see text] with the observed data within the temperature intervals studied for DMAKCr and perovskite HyFe. From our predictions, we find that magnetization decreases continuously whereas the inverse susceptibility decreases linearly with increasing temperature toward the transition temperature in those MOFs as expected for a weakly first-order transition from the mean field model.

TWISTED SYMMETRY AND NONCOMMUTATIVE FIELD THEORY

2012 ◽  
Vol 13 ◽  
pp. 54-65
Author(s):  
MARIJA DIMITRIJEVIĆ ◽  
LARISA JONKE
Keyword(s):  
Field Theory ◽  
Effective Action ◽  
Degrees Of Freedom ◽  
Deformation Parameter ◽  
Field Theories ◽  
Gauge Field Theory ◽  
Noncommutative Field Theory ◽  
First Order ◽  
Minkowski Space Time ◽  
Noncommutative Spaces

Although the meaning of twisted symmetry is still not fully understood, the twist approach has its advantages in the construction of field theories on noncommutative spaces. We discuss these advantages on the example of κ-Minkowski space-time. We construct the noncommutative U(1) gauge field theory. Especially the action is written as an integral of a maximal form, thus solving the cyclicity problem of the integral in κ-Minkowski. Using the Seiberg-Witten map to relate noncommutative and commutative degrees of freedom the effective action with the first order corrections in the deformation parameter is obtained.

scholarly journals Ginzburg-Landau effective action for a fluctuating holographic superconductor

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Yanyan Bu ◽  
Mitsutoshi Fujita ◽  
Shu Lin
Keyword(s):  
Effective Action ◽  
Order Parameter ◽  
Analytical Approach ◽  
Time Derivative ◽  
Time Dependent ◽  
Equilibrium System ◽  
Holographic Superconductor ◽  
Fluctuation Effect ◽  
Ginzburg Landau ◽  
First Order

Abstract Under holographic prescription for Schwinger-Keldysh closed time contour for non-equilibrium system, we consider fluctuation effect of the order parameter in a holographic superconductor model. Near the critical point, we derive the time-dependent Ginzburg-Landau effective action governing dynamics of the fluctuating order parameter. In a semi-analytical approach, the time-dependent Ginzburg-Landau action is computed up to quartic order of the fluctuating order parameter, and first order in time derivative.

scholarly journals T-dualization of Gödel string cosmologies via Poisson–Lie T-duality approach

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Ali Eghbali ◽  
Reza Naderi ◽  
Adel Rezaei-Aghdam
Keyword(s):  
Lie Groups ◽  
Effective Action ◽  
Three Dimensional ◽  
Target Space ◽  
Loop Order ◽  
Field Equations ◽  
First Order ◽  
Self Duality ◽  
Duality Approach ◽  
Dual Models

AbstractUsing the homogeneous Gödel spacetimes we find some new solutions for the field equations of bosonic string effective action up to first order in $$\alpha '$$ α ′ including both dilaton and axion fields. We then discuss in detail the (non-)Abelian T-dualization of Gödel string cosmologies via the Poisson–Lie (PL) T-duality approach. In studying Abelian T-duality of the models we get seven dual models in such a way that they are constructed by one-, two- and three-dimensional Abelian Lie groups acting freely on the target space manifold. The results of our study show that the Abelian T-dual models are, under some of the special conditions, self-dual; moreover, by applying the usual rules of Abelian T-duality without further corrections, we are still able to obtain two-loop solutions. We also study the Abelian T-duality of Gödel string cosmologies up to $$\alpha '$$ α ′ -corrections by using the T-duality rules at two-loop order derived by Kaloper and Meissner. Afterwards, non-Abelian duals of the Gödel spacetimes are constructed by two- and three-dimensional non-Abelian Lie groups such as $$A_2$$ A 2 , $$A_2 \oplus A_1$$ A 2 ⊕ A 1 and $$SL(2, \mathbb {R})$$ S L ( 2 , R ) . In this way, the PL self-duality of $$AdS_3 \times \mathbb {R}$$ A d S 3 × R space is discussed.

scholarly journals A Class of Non-Singular Gravi–Dilaton Backgrounds

1997 ◽  
Vol 12 (25) ◽  
pp. 1883-1889 ◽  
Author(s):  
A. Buonanno ◽  
C. Ungarelli ◽  
M. Gasperini
Keyword(s):  
Effective Action ◽  
Finite Size ◽  
Singular Solutions ◽  
Tree Level ◽  
Spherically Symmetric ◽  
De Sitter ◽  
First Order ◽  
Time Singularities ◽  
Symmetric States ◽  
Peak Value

We present a class of static, spherically symmetric, non-singular solutions of the tree-level string effective action, truncated to first order in α′. In the string frame the solutions approach asymptotically (as r→ 0 and r→∞) two different anti-de Sitter configurations, thus interpolating between two maximally symmetric states of different constant curvatures. The radial-dependent dilaton defines a string coupling which is everywhere finite, with a peak value that can be chosen arbitrarily small so as to neglect quantum-loop corrections. This example stresses the possible importance of finite-size α′ corrections, typical of string theory, in avoiding space–time singularities.

scholarly journals Composite operator approach to dynamical mass generation in the (2 + 1)-dimensional Gross–Neveu model

2021 ◽  
Author(s):  
T. G. Khunjua ◽  
K. G. Klimenko ◽  
R. N. Zhokhov
Keyword(s):  
Effective Action ◽  
Phase Structure ◽  
Coupling Constant ◽  
Operator Approach ◽  
Mass Generation ◽  
Dynamical Mass ◽  
Cutoff Parameter ◽  
First Order ◽  
Bare Coupling Constant ◽  
Gross Neveu Model

Using a nonperturbative approach based on the Cornwall–Jackiw–Tomboulis (CJT) effective action [Formula: see text] for composite operators, the phase structure of the simplest massless [Formula: see text]-dimensional Gross–Neveu model is investigated. We have calculated [Formula: see text] in the first-order of the bare coupling constant [Formula: see text] and have shown that there exist three different specific dependences of [Formula: see text] on the cutoff parameter [Formula: see text], and in each case, the effective action and its stationarity equations have been obtained. The solutions of these equations correspond to the fact that three different masses of fermions can arise dynamically and, respectively, three different nontrivial phases can be observed in the model.

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