Full Professor (Chair for Computational Mathematics) at the University of Vienna, Austria
This Insight article presents the main features of a conceptual foundation of quantum physics with the same characteristic features as classical physics – except that the density operator takes the place of the classical phase space coordinates position and momentum. Since everything follows from the well-established techniques of quantum tomography (the art and science of…
For reference purposes and to help focus discussions on Physics Forums in interpretation questions on the real issues, there is a need for fixing the common ground. There is no consensus about the interpretation of quantum mechanics, and – not surprisingly – there is disagreement even among the mentors and science advisors here on Physics…
Introduction Commonly there is a lot of imprecision in talking about ”indistinguishable” (or ”identical”) particles, even in serious work. This Insight article clarifies the issues involved in a conceptually precise way. Classical mechanics Historically, indistinguishable particles were introduced in order to explain the failure of the thermodynamics of a Newtonian ##N##-particle system to describe the…
Preface (-: ##~~~## A fantasy to be read at leisure time ##~~~## :-) Background & Links Written October 7, 1999 to relax from the strains of working on a new interpretation of quantum mechanics – at that time only an actively pursued dream, which took nearly 20 years to fully materialize two weeks ago! (-: :-)…
This Insight article is part of my paper Foundations of quantum physics III. Measurement, featuring the thermal interpretation of quantum physics. See this discussion. $$\def\D{\displaystyle} % display style \def\SS {{\bf S}} \def\Bsymbol#1{{\bm #1}} \def\Bsigma{{\sigma}} \def\half{\frac{1}{2}} \def\<{\langle} % expectation \def\>{\rangle} % expectation \def\fct#1{\mathop{\rm #1}} % e.g., \fct{tr} \def\fns#1{{\mbox{\rm \scriptsize#1}}} % subscript text \def\Tr{{\fct{Tr}}}$$ Stokes’ quantum counter. One…
Please give us a brief background on yourself Over 40 years ago, I studied mathematics, physics and computer science in Freiburg and Berlin (Germany). My Ph.D. thesis was in pure mathematics, but I was later drawn more and more into applied mathematics. Since 1994 I have been a full professor of mathematics at the University…
Introduction and context This Insight Article is a sequel of the Insight Articles ”The Physics of Virtual Particles”, “Misconceptions about Virtual Particles“ , and ”The Vacuum Fluctuation Myth”, which make precise what a virtual particle is, what being real means, document some of the liberties taken in physics textbooks in the use of this concept,…
This Insight Article is a sequel of the Insight Articles ”The Physics of Virtual Particles” and “Misconceptions about Virtual Particles“ which make precise what a virtual particle is and what being real means, document some of the liberties taken in physics textbooks in the use of this concept, and mention the most prominent misuses. A further…
Introduction This Insight Article is a sequel to the Insight Article ”The Physics of Virtual Particles”, which contains an exposition of definitions that are physically justified, and in particular, makes precise what a virtual particle is and what being real means. As discussed in detail in the companion article, virtual particles are defined as (intuitive…
In discussions on the internet (including a number of Wikipedia pages) and in books and articles for non-experts in particle physics, there is considerable confusion about various notions around the concept of particles of subatomic size, and in particular about the notion of a virtual particle. This is partly due to misunderstandings in the terminology…
Relativistic quantum field theory is notorious for the occurrence of divergent expressions that must be renormalized by recipes that on first sight sound very arbitrary and counterintuitive. But it doesn’t have to be this way… Traditional approaches The starting point of any quantum field theory is free fields that serve to define irreducible representations of…