Search results for "theoretical physics"

Hyperboloidal slicing approach to quasinormal mode expansions: The Reissner-Nordström case

2018

We study quasi-normal modes of black holes, with a focus on resonant (or quasi-normal mode) expansions, in a geometric frame based on the use of conformal compactifications together with hyperboloidal foliations of spacetime. Specifically, this work extends the previous study of Schwarzschild in this geometric approach to spherically symmetric asymptotically flat black hole spacetimes, in particular Reissner-Nordstr\"om. The discussion involves, first, the non-trivial technical developments needed to address the choice of appropriate hyperboloidal slices in the extended setting as well as the generalization of the algorithm determining the coefficients in the expansion of the solution in te…

Spin as Primordial Self-Referential Process Driving Quantum Mechanics, Spacetime Dynamics and Consciousness

2007

We have recently theorized that consciousness is intrinsically connected to quantum mechanical spin since said spin is embedded in the microscopic structure of spacetime and is more fundamental than spacetime itself, that is, spin is the “mind-pixel.” Applying these ideas to the particular structures and dynamics of the brain, we have developed a qualitative model of quantum consciousness. In this paper, we express our fundamental view that spin is a primordial self-referential process driving quantum mechanics, spacetime dynamics and consciousness. To justify such a view, we will draw support from existing literatures, discuss from a reductionist perspective the essential properties said s…

Route towards Dirac and Weyl antiferromagnetic spintronics

2017

Topological quantum matter and spintronics research have been developed to a large extent independently. In this Review we discuss a new role that the antiferromagnetic order has taken in combining topological matter and spintronics. This occurs due to the complex microscopic symmetries present in antiferromagnets that allow, e.g., for topological relativistic quasiparticles and the newly discovered N\'{e}el spin-orbit torques to coexist. We first introduce the concepts of topological semimetals and spin-orbitronics. Secondly, we explain the antiferromagnetic symmetries on a minimal Dirac semimetal model and the guiding role of $\textit{ab initio}$ calculations in predictions of examples of…

Towards the field theory of the Standard Model on fractional D6-branes on T6 /ℤ6 ′ : Yukawa couplings and masses

2012

We present the perturbative Yukawa couplings of the Standard Model on fractional intersecting D6-branes on T6/Z6' and discuss two mechanisms of creating mass terms for the vector-like particles in the matter spectrum, through perturbative three-point couplings and through continuous D6-brane displacements.

On the ambiguities of sign determination of the S-matrix from energy levels in a finite box

2013

In a recent paper the authors make a study on the determination of the S-matrix elements for scattering of particles in the infinite volume from the energy levels in a finite box for the case of multiple channels. The study is done with a toy model in 1+1 dimension and the authors find that there is some ambiguity in the sign of nondiagonal matrix elements, casting doubts on whether the needed observables in the infinite volume can be obtained from the energy levels of the box. In this paper I present an easy derivation, confirming the ambiguity of the sign and argue that this, however, does not put restrictions in the determination of observables.

Unraveling the nature of universal dynamics in $O(N)$ theories

2020

Many-body quantum systems far from equilibrium can exhibit universal scaling dynamics which defy standard classification schemes. Here, we disentangle the dominant excitations in the universal dynamics of highly-occupied $N$-component scalar systems using unequal-time correlators. While previous equal-time studies have conjectured the infrared properties to be universal for all $N$, we clearly identify for the first time two fundamentally different phenomena relevant at different $N$. We find all $N\geq3$ to be indeed dominated by the same Lorentzian ``large-$N$'' peak, whereas $N=1$ is characterized instead by a non-Lorentzian peak with different properties, and for $N=2$ we see a mixture …

Classical anomalies of supersymmetric extended objects

1991

Abstract The hamiltonian form of the action for a p-extended supersymmetric object is presented, and used to deduce both the algebra generated by the constraints, in agreement with previous results for p=1,2, and the algebra of the supersymmetry charges. The “anomalous” contributions in each algebra (for given p) are shown to be related, and the origin of their different properties is exhibited. In particular, it is shown why only in the charge algebra are the “anomalous” contributions always topological and the commutators of the translations always zero.

Kolmogorovian statistical invariants for the aspect-rapisarda experiment

1984

Analytically solvable 2×2 PT -symmetry dynamics from su(1,1)-symmetry problems

2019

A protocol for explicitly constructing the exact time-evolution operators generated by $2\ifmmode\times\else\texttimes\fi{}2$ time-dependent $PT$-symmetry Hamiltonians is reported. Its mathematical applicability is illustrated with the help of appropriate examples. The physical relevance of the proposed approach within gain-loss system scenarios, like two coupled waveguides, is discussed in detail.

Super Heavy Elements - experimental developments

2018

With his theoretical work Walter Greiner, our mentor, pioneered super heavy element research and motivated us young scientists. He actively shaped the profile of GSI. We are happy that still during his lifetime we could prove some of his predictions: Fusion with magic nuclei paving the way to super heavy elements and the proof of the prediction of the nuclear species existing only by shell stabilization, super heavy elements. With the discovery of oganesson, Z=118, the heaviest element known today, we have come to the end of this era. New experimental developments will be discussed.