Manifest non-locality in quantum mechanics, quantum field theory and quantum gravity

2019 ◽  
Vol 34 (28) ◽  
pp. 1941004
Author(s):  
Laurent Freidel ◽  
Robert G. Leigh ◽  
Djordje Minic
Keyword(s):  
Quantum Theory ◽  
String Theory ◽  
Quantum Gravity ◽  
Closed String ◽  
Covariant Formulation ◽  
Quantum Field ◽  
Quantum Geometry ◽  
Local Quantum ◽  
Generic Representation ◽  
Non Locality

We summarize our recent work on the foundational aspects of string theory as a quantum theory of gravity. We emphasize the hidden quantum geometry (modular spacetime) behind the generic representation of quantum theory and then stress that the same geometric structure underlies a manifestly T-duality covariant formulation of string theory, that we call metastring theory. We also discuss an effective non-commutative description of closed strings implied by intrinsic non-commutativity of closed string theory. This fundamental non-commutativity is explicit in the metastring formulation of quantum gravity. Finally we comment on the new concept of metaparticles inherent to such an effective non-commutative description in terms of bi-local quantum fields.

scholarly journals Holographic complexity of LST and single trace $$ T\overline{T} $$

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Soumangsu Chakraborty ◽  
Gaurav Katoch ◽  
Shubho R. Roy
Keyword(s):  
String Theory ◽  
Finite Temperature ◽  
Temperature Correction ◽  
Quantum Field ◽  
Zero Temperature ◽  
Local Quantum ◽  
Linear Dilaton ◽  
Single Trace ◽  
Distance Behavior ◽  
Non Locality

Abstract In this work, we continue our study of string theory in the background that interpolates between AdS3 in the IR to flat spacetime with a linear dilaton in the UV. The boundary dual theory interpolates between a CFT2 in the IR to a certain two-dimensional Little String Theory (LST) in the UV. In particular, we study computational complexity of such a theory through the lens of holography and investigate the signature of non-locality in the short distance behavior of complexity. When the cutoff UV scale is much smaller than the non-locality (Hagedorn) scale, we find exotic quadratic and logarithmic divergences (for both volume and action complexity) which are not expected in a local quantum field theory. We also generalize our computation to include the effects of finite temperature. Up to second order in finite temperature correction, we do not any find newer exotic UV-divergences compared to the zero temperature case.

Topology knots and hierarchy problem

2019 ◽  
Author(s):  
Vitaly Kuyukov
Keyword(s):  
Quantum Theory ◽  
String Theory ◽  
Quantum Gravity ◽  
Dimensional Space ◽  
Space Time ◽  
Elementary Particles ◽  
Hierarchy Problem ◽  
Topological Quantum ◽  
Dimensional Space Time ◽  
New Formula

Many approaches to quantum gravity consider the revision of the space-time geometry and the structure of elementary particles. One of the main candidates is string theory. It is possible that this theory will be able to describe the problem of hierarchy, provided that there is an appropriate Calabi-Yau geometry. In this paper we will proceed from the traditional view on the structure of elementary particles in the usual four-dimensional space-time. The only condition is that quarks and leptons should have a common emerging structure. When a new formula for the mass of the hierarchy is obtained, this structure arises from topological quantum theory and a suitable choice of dimensional units.

scholarly journals Quantum gravity, dynamical phase-space and string theory

2014 ◽  
Vol 23 (12) ◽  
pp. 1442006 ◽  
Author(s):  
Laurent Freidel ◽  
Robert G. Leigh ◽  
Djordje Minic
Keyword(s):  
Quantum Theory ◽  
Phase Space ◽  
String Theory ◽  
Quantum Gravity ◽  
Momentum Space ◽  
Symplectic Geometry ◽  
Complex Geometry ◽  
Hamiltonian Dynamics ◽  
Natural Extension ◽  
Dynamical Phase

In a natural extension of the relativity principle, we speculate that a quantum theory of gravity involves two fundamental scales associated with both dynamical spacetime as well as dynamical momentum space. This view of quantum gravity is explicitly realized in a new formulation of string theory which involves dynamical phase-space and in which spacetime is a derived concept. This formulation naturally unifies symplectic geometry of Hamiltonian dynamics, complex geometry of quantum theory and real geometry of general relativity. The spacetime and momentum space dynamics, and thus dynamical phase-space, is governed by a new version of the renormalization group (RG).

QUANTUM CLOSED STRINGS FROM MINIMAL AREA

1990 ◽  
Vol 05 (32) ◽  
pp. 2753-2762 ◽  
Author(s):  
BARTON ZWIEBACH
Keyword(s):  
Exact Solution ◽  
Quantum Theory ◽  
String Theory ◽  
Master Equation ◽  
Closed String ◽  
Feynman Rules ◽  
Higher Genus ◽  
Quantum Action ◽  
Full Quantum ◽  
Minimal Area

Canonical and factorizable off-shell amplitudes for covariant closed string theory can be obtained from string diagrams of minimal area. Evidence is given that all higher genus minimal area string diagrams can be built using vertices and propagators, implying that the off-shell amplitudes arise from the Feynman rules of a full quantum theory of closed strings. The quantum action gives an exact solution of the full master equation of Batalin and Vilkoviski.

Time in Quantum Gravity

2011 ◽  
Author(s):  
Claus Kiefer
Keyword(s):  
Quantum Theory ◽  
String Theory ◽  
Quantum Gravity ◽  
Special Relativity ◽  
Loop Quantum Gravity ◽  
Problem Of Time ◽  
Canonical Quantum Gravity ◽  
Time Loop ◽  
Canonical Quantum

This chapter notes that quantum gravity places the concept of time on a new level. In the absence of experimental hints, mathematical and conceptual issues must be chosen as the guides in the search for such a theory. Just as reconceiving classical notions of time was key for Einstein, in his discovery of special relativity, so too many believe that time will again hold the clue for theoretical advancement, but this time with quantum gravity. The chapter details the challenge of reconciling quantum theory with relativity, concentrating especially on why time in particular causes trouble. It describes a result in canonical quantum gravity which is possibly of signal importance, namely, that fundamentally there is no time at all, and discusses the problem of time, quantization, semiclassical time, loop quantum gravity, and string theory.

scholarly journals Emergence of stringlike physics from Lorentz invariance in loop quantum gravity

2014 ◽  
Vol 23 (12) ◽  
pp. 1442023 ◽  
Author(s):  
Rodolfo Gambini ◽  
Jorge Pullin
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
String Theory ◽  
Quantum Gravity ◽  
Loop Quantum Gravity ◽  
Lorentz Invariance ◽  
Spherically Symmetric ◽  
Quantum Field ◽  
Spin Network ◽  
Symmetric Quantum

We consider a quantum field theory on a spherically symmetric quantum spacetime described by loop quantum gravity. The spin network description of spacetime in such a theory leads to equations for the quantum field that are discrete. We show that to avoid significant violations of Lorentz invariance, one needs to consider specific nonlocal interactions in the quantum field theory similar to those that appear in string theory. This is the first sign that loop quantum gravity places restrictions on the type of matter considered, and points to a connection with string theory physics.

scholarly journals The landscape and the multiverse: What’s the problem?

Synthese ◽  
2021 ◽  
Author(s):  
James Read ◽  
Baptiste Le Bihan
Keyword(s):  
String Theory ◽  
Quantum Gravity ◽  
Current Source ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
The Past ◽  
Empirical Criterion ◽  
Scientific Status ◽  
Vast Range

AbstractAs a candidate theory of quantum gravity, the popularity of string theory has waxed and waned over the past four decades. One current source of scepticism is that the theory can be used to derive, depending upon the input geometrical assumptions that one makes, a vast range of different quantum field theories, giving rise to the so-called landscape problem. One apparent way to address the landscape problem is to posit the existence of a multiverse; this, however, has in turn drawn heightened attention to questions regarding the empirical testability and predictivity of string theory. We argue first that the landscape problem relies on dubious assumptions and does not motivate a multiverse hypothesis. Nevertheless, we then show that the multiverse hypothesis is scientifically legitimate and could be coupled to string theory for other empirical reasons. Looking at various cosmological approaches, we offer an empirical criterion to assess the scientific status of multiverse hypotheses.

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