889 research outputs found
From relativistic to quantum universe: Observation of a spatially-discontinuous particle dynamics beyond relativity
We perform an experimental test where we directly observe light-induced
electron transitions with a macroscopic spatial discontinuity. The effect is
related to the fundamental indivisibility of macroscopic orbit-like quantum
states reminiscent of so-called extended states in the integer quantum Hall
system. The test has become realizable due to the discovering of a quantum
phase with spontaneous pervasive quantum ordering reminiscent of that of a
single atom. The observed transitions may be regarded as a peculiar quantum
dynamics beyond relativity, which implies that the current relativistic model
of universe should be replaced by a deeper quantum model. It is the Bohm's
model of undivided universe, which now should involve a deeper-than-classical
concept of absolute simultaneity and a deeper-than-relativistic concept of
space and time. Ultimately, our test thus establishes a new hierarchy of
fundamental physical theories where the de Broglie-Bohm realistic quantum
theory is the deepest theory which does not contradict either classical physics
or relativity but rather is beyond both. This is because the fact that quantum
theory is dealing with a deeper reality where physical objects are not
self-sufficient entities and therefore their discontinuous transitions are
possible within an overall quantum system which may well be macroscopic
Order convergence in infinite-dimensional vector lattices is not topological
In this note, we show that the order convergence in a vector lattice is
not topological unless . Furthermore, we show that, in atomic
order continuous Banach lattices, the order convergence is topological on order
intervals
On free fall of fermions and antifermions
We propose a model describing spin-half quantum particles in curved spacetime in the framework of quantum field theory. Our model is based on embodying Einstein’s equivalence principle and general covariance in the definition of quantum-particle states. With this model at hand, we compute several observables which characterise spin-half quantum particles in a gravitational field. In particular, we find that spin precesses in a normal Fermi frame, even in the absence of torsion. The effect appears to be complementary to free-fall non-universality we have recently reported about for spinless quantum particles. Furthermore, we find that quantum-particle gravitational-potential energy is insensitive to wave-packet spreading in the Earth’s gravitational field, that is responsible for the non-universality of free fall in quantum theory. This theoretical result provides another channel for the experimental study of our quantum-particle model by using gravitational spectrometers. Finally, we also find that (elementary) fermions and antifermions are indistinguishable in gravity
On quantum corrections to geodesics in de-Sitter spacetime
We find a coordinate-independent wave-packet solution of the massive Klein–Gordon equation with the conformal coupling to gravity in the de-Sitter universe. This solution can locally be represented through the superposition of positive-frequency plane waves at any space-time point, assuming that the scalar-field mass M is much bigger than the de-Sitter Hubble constant H. The solution is also shown to be related to the two-point function in the de-Sitter quantum vacuum. Moreover, we study the wave-packet propagation over cosmological times, depending on the ratio of M and H. In doing so, we find that this wave packet propagates like a point-like particle of the same mass if ⋙ , but, if otherwise, the wave packet behaves highly non-classically
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