scholarly journals Cross section and effective potential in asymptotically free scalar field theories

1998 ◽  
Vol 57 (10) ◽  
pp. 6337-6341 ◽  
Author(s):  
Kenneth Halpern
Keyword(s):  
Scalar Field ◽  
Cross Section ◽  
Effective Potential ◽  
Field Theories ◽  
Free Scalar

scholarly journals Canonical Quantization of the Scalar Field: The Measure Theoretic Perspective

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
José Velhinho
Keyword(s):  
Scalar Field ◽  
Canonical Quantization ◽  
Field Theories ◽  
Quantum Fields ◽  
Theoretical Methods ◽  
Local Properties ◽  
Free Scalar ◽  
Free Fields ◽  
Field Behaviour

This review is devoted to measure theoretical methods in the canonical quantization of scalar field theories. We present in some detail the canonical quantization of the free scalar field. We study the measures associated with the free fields and present two characterizations of the support of these measures. The first characterization concerns local properties of the quantum fields, whereas for the second one we introduce a sequence of variables that test the field behaviour at large distances, thus allowing distinguishing between the typical quantum fields associated with different values of the mass.

scholarly journals Noncommutative Friedmann equations in effective LQC

2020 ◽  
Vol 29 (06) ◽  
pp. 2050039
Author(s):  
Luis Rey Díaz-Barrón ◽  
Abraham Espinoza-García ◽  
S. Pérez-Payán ◽  
J. Socorro
Keyword(s):  
Scalar Field ◽  
Effective Potential ◽  
Quantum Cosmology ◽  
Equations Of Motion ◽  
Loop Quantum Cosmology ◽  
Friedmann Equations ◽  
Noncommutative Version ◽  
Previous Proposal ◽  
Free Scalar ◽  
Raychaudhuri Equations

In this work, we construct a noncommutative version of the Friedmann equations in the framework of effective loop quantum cosmology, extending and applying the ideas presented in a previous proposal by some of the authors. The model under consideration is a flat FRW spacetime with a free scalar field. First, noncommutativity in the momentum sector is introduced. We establish the noncommutative equations of motion and obtain the corresponding exact solutions. Such solutions indicate that the bounce is preserved, in particular, the energy density is the same as in the standard LQC. We also construct an extension of the modified Friedmann equations arising in effective LQC which incorporates corrections due to noncommutativity, and argue that an effective potential is induced. This, in turn, leads us to investigate the possibility of an inflationary era. Finally, we obtain the Friedmann and the Raychaudhuri equations when implementing noncommutativity in the configuration sector. In this case, no effective potential is induced.

scholarly journals Quantum of the bare cosmological constant

2020 ◽  
Vol 2020 (4) ◽  
Author(s):  
Farhang Loran
Keyword(s):  
Scalar Field ◽  
Cosmological Constant ◽  
Stress Tensor ◽  
Parameter Space ◽  
Field Theories ◽  
Classical Solutions ◽  
Curved Spacetimes ◽  
Free Scalar ◽  
Scalar Theories

Abstract We show that there exist scalar field theories with plausible one-particle states in general $D$-dimensional nonstationary curved spacetimes whose propagating modes are localized on $d\le D$ dimensional hypersurfaces, and the corresponding stress tensor resembles the bare cosmological constant $\lambda_{\rm B}$ in the $D$-dimensional bulk. We show that nontrivial $d=1$ dimensional solutions correspond to $\lambda_{\rm B}< 0$. Considering free scalar theories, we find that for $d=2$ the symmetry of the parameter space of classical solutions corresponding to $\lambda_{\rm B}\neq 0$ is $O(1,1)$, which enhances to $\mathbb{Z}_2\times{\rm Diff}(\mathbb{R}^1)$ at $\lambda_{\rm B}=0$. For $d>2$ we obtain $O(d-1,1)$, $O(d-1)\times {\rm Diff}(\mathbb{R}^1)$, and $O(d-1,1)\times O(d-2)\times {\rm Diff}(\mathbb{R}^1)$ corresponding to, respectively, $\lambda_{\rm B}<0$, $\lambda_{\rm B}=0$, and $\lambda_{\rm B}>0$.

scholarly journals Entanglement of purification in free scalar field theories

2018 ◽  
Vol 2018 (4) ◽  
Author(s):  
Arpan Bhattacharyya ◽  
Tadashi Takayanagi ◽  
Koji Umemoto
Keyword(s):  
Scalar Field ◽  
Field Theories ◽  
Free Scalar

scholarly journals Weak cosmic censorship with self-interacting scalar and bound on charge to mass ratio

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Yan Song ◽  
Tong-Tong Hu ◽  
Yong-Qiang Wang
Keyword(s):  
Scalar Field ◽  
Scalar Fields ◽  
Cosmic Censorship ◽  
Mass Ratio ◽  
Quartic Coupling ◽  
Scalar Theory ◽  
Free Scalar ◽  
The One ◽  
Nonzero Scalar ◽  
Large Charge

Abstract We study the model of four-dimensional Einstein-Maxwell-Λ theory minimally coupled to a massive charged self-interacting scalar field, parameterized by the quartic and hexic couplings, labelled by λ and β, respectively. In the absence of scalar field, there is a class of counterexamples to cosmic censorship. Moreover, we investigate the full nonlinear solution with nonzero scalar field included, and argue that these counterexamples can be removed by assuming charged self-interacting scalar field with sufficiently large charge not lower than a certain bound. In particular, this bound on charge required to preserve cosmic censorship is no longer precisely the weak gravity bound for the free scalar theory. For the quartic coupling, for λ < 0 the bound is below the one for the free scalar fields, whereas for λ > 0 it is above. Meanwhile, for the hexic coupling the bound is always above the one for the free scalar fields, irrespective of the sign of β.

scholarly journals Monte Carlo and renormalization-group effective potentials in scalar field theories

1995 ◽  
Vol 51 (12) ◽  
pp. 7017-7025 ◽  
Author(s):  
J. R. Shepard ◽  
V. Dmitrašinović ◽  
J. A. McNeil
Keyword(s):  
Monte Carlo ◽  
Renormalization Group ◽  
Scalar Field ◽  
Field Theories ◽  
Effective Potentials
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