scholarly journals CPT VIOLATION IN STRING-MODIFIED QUANTUM MECHANICS AND THE NEUTRAL-KAON SYSTEM

1996 ◽  
Vol 11 (08) ◽  
pp. 1489-1507 ◽  
Author(s):  
JOHN ELLIS ◽  
N.E. MAVROMATOS ◽  
D.V. NANOPOULOS
Keyword(s):  
Quantum Mechanics ◽  
Neutral Kaon ◽  
Low Energy ◽  
Target Space ◽  
Quantum Mechanical ◽  
Cpt Violation ◽  
World Sheet ◽  
String Phenomenology ◽  
Quantum Mechanical Description ◽  
Energy Theory

We argue that CPT is in general violated in a non-quantum-mechanical way in the effective low-energy theory derived from noncritical string theory, in which pure states evolve into mixed states in general. It is known that such a dynamical framework violates the strong form of CPT invariance. We relate CPT violation in the effective low-energy theory in our formalism to apparent world-sheet charge nonconservation induced by stringy monopoles corresponding to target-space black-hole configurations. We prove that energy is conserved on the average in this CPT-violating modification of quantum mechanics. The magnitude of the effective spontaneous violation of CPT may not be far from the present experimental sensitivity in the neutral-kaon system. We demonstrate that previously proposed phenomenological modifications to the quantum-mechanical description of the neutral-kaon system violate CPT, although in a different way from that assumed in analyses within conventional quantum mechanics. We sketch the way to constrain the novel CPT-violating parameters using available data on KL→2π, KS→ 3π0 and semileptonic KL,S decay asymmetries. Could non-quantum-field-theoretical and non-quantum-mechanical CPT violation usher in the long-awaited era of string phenomenology?

scholarly journals Did bohr succeed in defending the completeness of quantum mechanics?

2020 ◽  
Vol 24 (1) ◽  
pp. 51-63
Author(s):  
Kunihisa Morita
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Recent Trend ◽  
Physical Reality ◽  
Current Paper ◽  
Quantum Mechanical ◽  
Mechanical Description ◽  
Quantum Mechanical Description ◽  
Completeness Of Quantum Mechanics

This study posits that Bohr failed to defend the completeness of the quantum mechanical description of physical reality against Einstein–Podolsky–Rosen’s (EPR) paper. Although there are many papers in the literature that focus on Bohr’s argument in his reply to the EPR paper, the purpose of the current paper is not to clarify Bohr’s argument. Instead, I contend that regardless of which interpretation of Bohr’s argument is correct, his defense of the quantum mechanical description of physical reality remained incomplete. For example, a recent trend in studies of Bohr’s work is to suggest he considered the wave-function description to be epistemic. However, such an interpretation cannot be used to defend the completeness of the quantum mechanical description.

scholarly journals STRINGS, NONCOMMUTATIVE GEOMETRY AND THE SIZE OF THE TARGET SPACE

1999 ◽  
Vol 14 (28) ◽  
pp. 4501-4517 ◽  
Author(s):  
FEDELE LIZZI
Keyword(s):  
String Theory ◽  
Dirac Operator ◽  
Noncommutative Geometry ◽  
Low Energy ◽  
Target Space ◽  
World Sheet ◽  
Crucial Point ◽  
Spectral Action ◽  
Energy Eigenvalues ◽  
The World

We describe how the presence of the antisymmetric tensor (torsion) on the world sheet action of string theory renders the size of the target space a gauge noninvariant quantity. This generalizes the R ↔ 1/R symmetry in which momenta and windings are exchanged, to the whole O(d,d,ℤ). The crucial point is that, with a transformation, it is possible always to have all of the lowest eigenvalues of the Hamiltonian to be momentum modes. We interpret this in the framework of noncommutative geometry, in which algebras take the place of point spaces, and of the spectral action principle for which the eigenvalues of the Dirac operator are the fundamental objects, out of which the theory is constructed. A quantum observer, in the presence of many low energy eigenvalues of the Dirac operator (and hence of the Hamiltonian) will always interpreted the target space of the string theory as effectively uncompactified.

scholarly journals Localization of the gauged linear sigma model for KK5-branes

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Yuki Hiraga ◽  
Yuki Sato
Keyword(s):  
Partition Function ◽  
Sigma Model ◽  
Low Energy ◽  
Target Space ◽  
Linear Sigma Model ◽  
Effective Theory ◽  
Coulomb Branch ◽  
World Sheet ◽  
The World ◽  
Gauged Linear Sigma Model

Abstract We study quantum aspects of the target space of the non-linear sigma model, which is a low-energy effective theory of the gauged linear sigma model (GLSM). As such, we especially compute the exact sphere partition function of the GLSM for KK$5$-branes whose background geometry is a Taub–NUT space, using the supersymmetric localization technique on the Coulomb branch. From the sphere partition function, we distill the world-sheet instanton effects. In particular, we show that, concerning the single-centered Taub–NUT space, instanton contributions exist only if the asymptotic radius of the $S^1$ fiber in the Taub–NUT space is zero.

scholarly journals GRAVITY AND YANG–MILLS THEORY

2010 ◽  
Vol 19 (14) ◽  
pp. 2379-2384 ◽  
Author(s):  
SUDARSHAN ANANTH
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Quantum Mechanical ◽  
Yang Mills ◽  
Mechanical Description ◽  
Quantum Mechanical Description ◽  
Theory Of Gravity

Three of the four forces of Nature are described by quantum Yang–Mills theories with remarkable precision. The fourth force, gravity, is described classically by the Einstein–Hilbert theory. There appears to be an inherent incompatibility between quantum mechanics and the Einstein–Hilbert theory which prevents us from developing a consistent quantum theory of gravity. The Einstein–Hilbert theory is therefore believed to differ greatly from Yang–Mills theory (which does have a sensible quantum mechanical description). It is therefore very surprising that these two theories actually share close perturbative ties. This essay focuses on these ties between Yang–Mills theory and the Einstein–Hilbert theory. We discuss the origin of these ties and their implications for a quantum theory of gravity.

scholarly journals Higgs Branch, Hyper-Kähler Quotient and Duality in SUSY N = 2 Yang–Mills Theories

1997 ◽  
Vol 12 (27) ◽  
pp. 4907-4931 ◽  
Author(s):  
I. Antoniadis ◽  
B. Pioline
Keyword(s):  
Moduli Space ◽  
Gauge Theories ◽  
Geometric Interpretation ◽  
Low Energy ◽  
Target Space ◽  
Field Theories ◽  
Yang Mills ◽  
Coulomb Phase ◽  
Supersymmetric Field Theories ◽  
Energy Theory

Low-energy limits of N = 2 supersymmetric field theories in the Higgs branch are described in terms of a nonlinear four-dimensional σ-model on a hyper-Kähler target space, classically obtained as a hyper-Kähler quotient of the original flat hypermultiplet space by the gauge group. We review in a pedagogical way this construction, and illustrate it in various examples, with special attention given to the singularities emerging in the low-energy theory. In particular, we thoroughly study the Higgs branch singularity of Seiberg–Witten SU(2) theory with Nf flavors, interpreted by Witten as a small instanton singularity in the moduli space of one instanton on ℝ4. By explicitly evaluating the metric, we show that this Higgs branch coincides with the Higgs branch of a U(1) N = 2 SUSY theory with the number of flavors predicted by the singularity structure of Seiberg–Witten's theory in the Coulomb phase. We find another example of Higgs phase duality, namely between the Higgs phases of U(Nc)Nf flavors and U(Nf-Nc)Nf flavors theories, by using a geometric interpretation due to Biquard et al. This duality may be relevant for understanding Seiberg's conjectured duality Nc ↔ Nf-Nc in N = 1 SUSY SU(Nc) gauge theories.

CAN QUANTUM-MECHANICAL DESCRIPTION OF PHYSICAL REALITY BE CONSIDERED INCOMPLETE?

2006 ◽  
Vol 04 (01) ◽  
pp. 45-54 ◽  
Author(s):  
GILLES BRASSARD ◽  
ANDRÉ ALLAN MÉTHOT
Keyword(s):  
Quantum Mechanics ◽  
Critical Analysis ◽  
Albert Einstein ◽  
Physical Reality ◽  
Quantum Mechanical ◽  
Mechanical Description ◽  
Quantum Mechanical Description ◽  
Influential Paper ◽  
Completeness Of Quantum Mechanics ◽  
Epr Argument

In loving memory of Asher Peres, we discuss a most important and influential paper written in 1935 by his thesis supervisor and mentor Nathan Rosen, together with Albert Einstein and Boris Podolsky. In that paper, the trio known as EPR questioned the completeness of quantum mechanics. The authors argued that the then-new theory should not be considered final because they believed it incapable of describing physical reality. The epic battle between Einstein and Bohr intensified following the latter's response later the same year. Three decades elapsed before John S. Bell gave a devastating proof that the EPR argument was fatally flawed. The modest purpose of our paper is to give a critical analysis of the original EPR paper and point out its logical shortcomings in a way that could have been done 70 years ago, with no need to wait for Bell's theorem. We also present an overview of Bohr's response in the interest of showing how it failed to address the gist of the EPR argument.

Quantum Superposition and Entanglement

2020 ◽  
pp. 154-171
Author(s):  
M. Suhail Zubairy
Keyword(s):  
Quantum Mechanics ◽  
Quantum Teleportation ◽  
Entangled State ◽  
Quantum Mechanical ◽  
The Novel ◽  
Quantum Superposition ◽  
Multiple Objects ◽  
Mechanical Description ◽  
Quantum Mechanical Description ◽  
Set Up

In this chapter, the notion of quantum superposition of states is introduced through the example of a polarized photon. This brings out the novel feature that the state of the system depends on how the experiment is set up. The paradoxical consequences of quantum superposition, such as a cat can be simultaneously dead and alive, are also discussed. This is the essence of the famous Schrödinger’s cat paradox. This description motivates another important consequence of quantum mechanical description of the multiple objects, namely, their ability to exist in an entangled state. The properties of the two objects can remain entangled no matter how far away they are from each other and thus have the ability to influence each other. After discussing these aspects of quantum mechanics, the application of quantum entanglement to novel phenomena of quantum teleportation and quantum swapping are presented.

TOPOLOGICAL QUANTUM MECHANICS IN 2+1 DIMENSIONS

1990 ◽  
Vol 05 (08) ◽  
pp. 1575-1595 ◽  
Author(s):  
B.-S. SKAGERSTAM ◽  
A. STERN
Keyword(s):  
Quantum Mechanics ◽  
Degrees Of Freedom ◽  
Flat Space ◽  
Noncommutative Space ◽  
Quantum Mechanical ◽  
De Sitter ◽  
Spinning Particles ◽  
Topological Quantum ◽  
Quantum Mechanical Description ◽  
Adjoint Orbits

We show that the classical and quantum covariant dynamics of spinning particles in flat space in 2+1 dimensions are derived from a pure Wess-Zumino term written on the space of adjoint orbits of the ISO(2, 1) group. Similarly, the dynamics of spinning particles in 2+1 de Sitter [anti-de Sitter] space are derived from a Wess-Zumino term on the space of adjoint orbits of SO(3, 1) [SO(2, 2)]. It is shown that a quantum mechanical description of spin is possible in 2+1 dimensions without introducing explicit spin degrees of freedom, but at the expense of having a noncommutative space-time geometry.

Operators and meaning of wave function

2016 ◽  
pp. 4039-4042
Author(s):  
Viliam Malcher
Keyword(s):  
Wave Function ◽  
Quantum Theory ◽  
State Vector ◽  
The State ◽  
Physical Significance ◽  
Central Problem ◽  
Quantum Mechanical ◽  
Mechanical Description ◽  
Quantum Mechanical Description ◽  
Interpretation Of Quantum Theory

The interpretation problems of quantum theory are considered. In the formalism of quantum theory the possible states of a system are described by a state vector. The state vector, which will be represented as |ψ> in Dirac notation, is the most general form of the quantum mechanical description. The central problem of the interpretation of quantum theory is to explain the physical significance of the |ψ>. In this paper we have shown that one of the best way to make of interpretation of wave function is to take the wave function as an operator.

Sign in / Sign up

Export Citation Format

Share Document