CONFORMAL SYMMETRY AND HIGGS EFFECT IN QUANTUM COSMOLOGY

1998 ◽  
Vol 13 (02) ◽  
pp. 119-131 ◽  
Author(s):  
V. N. PERVUSHIN ◽  
V. I. SMIRICHINSKI

We point out an important role of conformal invariant observables in the formulation of quantum cosmology with a normalizable wave function which bears a direct relationship to the Friedmann observational evolution of the Universe (with redshift and Hubble law). Conformal invariant field variables allow us to establish relation between standard cosmological models and quantum field theory actions. The conformal symmetry principle excludes the Higgs potential from the Weinberg–Salam model and includes the Penrose–Chernikov–Tagirov term. In the conformal version of the standard model for electroweak interaction unified with the Einstein gravity, the Higgs field is absorbed by the space metric so that the elementary particle masses and the evolution of the Universe have one and the same origin. In the flat-space limit we got the σ-version of the Weinberg–Salam model without the Higgs particle-like excitations.

2011 ◽  
Vol 26 (32) ◽  
pp. 2375-2389 ◽  
Author(s):  
PHILIP D. MANNHEIM

We propose that gravity be intrinsically quantum-mechanical, so that in the absence of quantum mechanics the geometry of the universe would be Minkowski. We show that in such a situation gravity does not require any independent quantization of its own, with it being quantized simply by virtue of its being coupled to the quantized matter fields that serve as its source. We show that when the gravitational and matter fields possess an underlying conformal symmetry, the gravitational field and fermionic matter-field zero-point fluctuations cancel each other identically. Then, when the fermions acquire mass by a dynamical symmetry breaking procedure that induces a cosmological constant in such conformal theories, the zero-point fluctuations readjust so as to cancel the induced cosmological constant identically. The zero-point vacuum problem and the cosmological constant vacuum problems thus mutually solve each other. We illustrate our ideas in a completely solvable conformal-invariant model, namely two-dimensional quantum Einstein gravity coupled to a Nambu–Jona-Lasinio self-consistent fermion.


2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Sourav Sur ◽  
Ashim Dutta ◽  
Hiyang Ramo Chothe

AbstractWe extend the basic formalism of mimetic-metric-torsion gravity theory, in a way that the mimetic scalar field can manifest itself geometrically as the source of not just the trace mode of torsion, but its axial (or, pseudo-trace) mode as well. Specifically, we consider the mimetic field to be (i) coupled explicitly to the well-known Holst extension of the Riemann–Cartan action, and (ii) identified with the square of the associated Barbero–Immirzi field, presumably a pseudo-scalar. The conformal symmetry originally prevaling in the theory would still hold, as the associated Cartan transformations do not affect the torsion pseudo-trace, and hence the Holst term. Demanding the theory to preserve the spatial parity symmetry as well, we show a geometric unification of the cosmological dark sector, and the feasibility of a super-accelerating regime in the course of evolution of the universe. From the observational perspective, assuming the cosmological evolution profile to be very close to that for $$\varLambda $$ Λ CDM, we further illustrate a smooth crossing of the so-called phantom barrier at a low red-shift, albeit with a restricted parametric domain. Subsequently, we determine the extent of the super-acceleration by examining the evolution of the relevant torsion parameters.


2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Luis F. Alday ◽  
Xinan Zhou

Abstract We demonstrate the simplicity of AdS5× S5 IIB supergravity at one loop level, by studying non-planar holographic four-point correlators in Mellin space. We develop a systematic algorithm for constructing one-loop Mellin amplitudes from the tree-level data, and obtain a simple closed form answer for the $$ \left\langle {\mathcal{O}}_2^{SG}{\mathcal{O}}_2^{SG}{\mathcal{O}}_p^{SG}{\mathcal{O}}_p^{SG}\right\rangle $$ O 2 SG O 2 SG O p SG O p SG correlators. The structure of this expression is remarkably simple, containing only simultaneous poles in the Mellin variables. We also study the flat space limit of the Mellin amplitudes, which reproduces precisely the IIB supergravity one-loop amplitude in ten dimensions. Our results provide nontrivial evidence for the persistence of the hidden conformal symmetry at one loop.


2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Congkao Wen ◽  
Shun-Qing Zhang

Abstract We present a compact formula in Mellin space for the four-point tree-level holographic correlators of chiral primary operators of arbitrary conformal weights in (2, 0) supergravity on AdS3× S3, with two operators in tensor multiplet and the other two in gravity multiplet. This is achieved by solving the recursion relation arising from a hidden six-dimensional conformal symmetry. We note the compact expression is obtained after carefully analysing the analytic structures of the correlators. Various limits of the correlators are studied, including the maximally R-symmetry violating limit and flat-space limit.


Think ◽  
2021 ◽  
Vol 21 (60) ◽  
pp. 33-49
Author(s):  
William Lyons

The author sets out to respond to the student complaint that ‘Philosophy did not answer “the big questions”’, in particular the question ‘What is the meaning of life?’ The response first outlines and evaluates the most common religious answer, that human life is given a meaning by God who created us and informs us that this life is just the pilgrim way to the next eternal life in heaven. He then discusses the response that, from the point of view of post-Darwinian science and the evolution of the universe and all that is in it, human life on Earth must be afforded no more meaning than the meaning we would give to a microscopic planaria or to some creature on another planet in a distant universe. All things including human creatures on Planet Earth just exist for a time and that is that. There is no plan or purpose. In the last sections the author outlines the view that it is we humans ourselves who give meaning to our lives by our choices of values or things that are worth pursuing and through our resulting sense of achievement or the opposite. Nevertheless the question ‘What is the meaning of life?’ can mean quite different things in different contexts, and so merit different if related answers. From one point of view one answer may lie in terms of the love of one human for another.


2021 ◽  
pp. 2150111
Author(s):  
Fei-Quan Tu ◽  
Bin Sun ◽  
Meng Wan ◽  
Qi-Hong Huang

Entropy is a key concept widely used in physics and other fields. At the same time, the meaning of entropy with different names and the relationship among them are confusing. In this paper, we discuss the relationship among the Clausius entropy, Boltzmann entropy and information entropy and further show that the three kinds of entropy are equivalent to each other to some extent. Moreover, we point out that the evolution of the universe is a process of entropy increment and life originates from the original low entropy of the universe. Finally, we discuss the evolution of the entire universe composed of the cosmological horizon and the space surrounded by it and interpret the entropy as a measure of information of all microstates corresponding to a certain macrostate. Under this explanation, the thermodynamic entropy and information entropy are unified and we can conclude that the sum of the entropy of horizon and the entropy of matter in the space surrounded by the horizon does not decrease with time if the second law of thermodynamics holds for the entire universe.


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