Time to think

WU Xin-zhong

In physics,a point in space corresponds to an in time.If particle models become invalid in relativity, then the instant concept will lose efficacy naturally in the quantum theory and the field theory.A real should be a small duration, it likes a time piece of past-precence-future.Our philosophical analysis about the time concept in quantum theory reveals the truth of speculative philosophy such as life philosophy,existentialism.This kind of philosophical analysis should connect with some concrete physical models.Niels Bohr thinked that time has physical meaning only when we measure a physical process.Erwin Schrodinger think that EPR correlation originates from conflicts between classical space-time and quantum space-time.Roger Penrose think that micro-space-time is compound folded.This paper gets a conclusion that the concept is like the particle model in quantum theory,they are ideal models when we ignore a space-time image of a moving body.

Nicolas Gisin

Valerio Scarani

Abstract Nature makes innumerable variations on the theme ‘indistinguishability principle’. In certain variations the theme is obvious, in others it is more hidden – exactly as in music. I have presented the phenomena that most directly show the specificity of quantum physics; but to think that this book contains all of quantum physics would be like killing Schubert’s Trout in the first octaves. Think of the historical successes of quantum physics – the comprehension of chemistry, the discovery of the atom first and the world of elementary particles afterwards. Think of the research domains that, apart from increasing our understanding of Nature, have produced important applications – quantum optics with the laser, solid-state physics with semiconductors and superconductors, atomic physics with the atomic clocks required for precise synchronicity (for instance in the GPS system). Think of the most recent but fascinating domains such as mesoscopic physics or the physics of the Bose–Einstein condensates91 produced for the first time in 1995. Think of the frontiers of cosmology, for instance the so-called inflation that is supposed to describe the very first instants of our universe. Think of the impetus that the needs of physics have given to certain branches of mathematics. Think of all that, and you will have a more comprehensive summary of what quantum physics is – each of these points deserves many books for itself alone.

Malcolm A. McCausland