Hidden Variables and Quantum Statistics Nature (original) (raw)
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Hidden variables and the nature of quantum statistics
2001
It is shown that the nature of quantum statistics can be clarified by assuming the existence of a background of random gravitational fields and waves, distributed isotropically in space. This background is responsible for correlating phases of oscillations of identical microobjects. If such a background of random gravitational fields and waves is considered as hidden variables, then taking it into account leads to Bell-type inequalities that are fairly consistent with experimental data.
Quantum randomness emerging under gravitational nonlinearity
2002
A scenario is outlined for quantum measurement, assuming that self-sustaining classicality is the consequence of an attractive gravitational self-interaction acting on massive bodies, and randomness arises already in the classical domain. A simple solvable model is used to demonstrate that small quantum systems influence big ones in a mean-field way, offering a natural route to Born's probability rule.
Quantum decoherence and gravitational waves
2008
The quite different behaviors exhibited by microscopic and macroscopic systems with respect to quantum interferences suggest the existence of a borderline beyond which quantum systems loose their coherences and can be described classically. Gravitational waves, generated within our galaxy or during the cosmic expansion, constitute a universal environment susceptible to lead to such a quantum decoherence mechanism. We assess this idea by studying the quantum decoherence due to gravitational waves on typical microscopic and macoscopic systems, namely an atom interferometer (HYPER) and the Earth-Moon system. We show that quantum interferences remain unaffected in the former case and that they disappear extremely rapidly in the latter case. We obtain the relevant parameters which, besides the ratio of the system's mass to Planck mass, characterize the loss of quantum coherences.
Discriminating quantum gravity models by gravitational decoherence
Nuclear Physics B
Several phenomenological approaches to quantum gravity assume the existence of a minimal measurable length and/or a maximum measurable momentum near the Planck scale. When embedded into the framework of quantum mechanics, such constraints induce a modification of the canonical commutation relations and thus a generalization of the Heisenberg uncertainty relations, commonly referred to as generalized uncertainty principle (GUP). Different models of quantum gravity imply different forms of the GUP. For instance, in the framework of string theory the GUP is quadratic in the momentum operator, while in the context of doubly special relativity it includes an additional linear dependence. Among the possible physical consequences, it was recently shown that the quadratic GUP induces a universal decoherence mechanism, provided one assumes a foamy structure of quantum spacetime close to the Planck length. Along this line, in the present work we investigate the gravitational decoherence associated to the linear-quadratic GUP and we compare it with the one associated to the quadratic GUP. We find that, despite their similarities, the two generalizations of the Heisenberg uncertainty principle yield decoherence times that are completely uncorrelated and significantly distinct. Motivated by this result, we introduce a theoretical and experimental scheme based on cavity optomechanics to measure the different time evolution of nonlocal quantum correlations corresponding to the two aforementioned decoherence mechanisms. We find that the deviation between the two predictions occurs on time scales that are macroscopic and thus potentially amenable to experimental verification. This scenario provides a possible setting to discriminate between different forms of the GUP and therefore different models of quantum gravity.
A comparison between models of gravity induced decoherence of the wavefunction
Journal of Physics: Conference Series, 2015
It has already been suggested that quantum theory needs to be reformulated or modified in order to explain the measurement process and the successive collapse of the wavefunction. However, there are also models of another type which keep quantum theory intact and instead modify the classical gravity by introducing stochasticity to it. These models suggest that there is a fluctuation in the background gravitational field which eventually results in the decoherence of the wavefunction. These fluctuations limit the precision with which one can measure the properties of a spacetime geometry with a quantum probe. Two similar models along this line have been suggested by Karolyhazy (K-model) and Diósi (D-model). They are based upon apparently different spacetime bounds. The results obtained for the coherence length are also somewhat different. In this article, we show that, given certain conditions apply, the minimal spacetime bounds in these two models are equivalent. We also derive the two-point correlation for the fluctuation potential in K-model which turns out to be non-white, unlike in D-model, where the corresponding correlation is white noise in time. In our opinion, this is the origin of discrepancy in the predictions of the two models. We argue that the noise correlation cannot be determined uniquely from a given spacetime bound.
The statistical fingerprints of quantum gravity
2008
This thesis puts a formal end to my twenty two years of life as a student. I should start by acknowledging my parents who played a significant role in my education and to whom I dedicate this thesis. My father, Abdolali Ansari, is the founder of the Teachers College of Kermanshah (Daneshsaraye Aali e Kermanshah) and was the first president of this College between 1955-1980. He has taught many courses in this college mainly on Mathematics and Persian literature. My father is the first person who implanted in me the joy of mathematics by spending hours with me motivating the discovery of new proofs for geometrical theorems. His passion for discovering laws between seemingly random numbers and also in working with rulers and compasses in his way for finding systematic methods for splitting angles into several pieces are among those memories that never will be eliminated from my memories. My mother, Fatemeh, sacrificed the blossom moments of her highschool education, which could easily lead to her university studies, helping her four children through every step of their lives and educations. I warmly thank her for everything she has done for us. My interest to Physics started in high school by the motivations I received from our young and curious physics teacher Mr. Mollanejad who was then a BSc. student of Mechanical engineering. Lateron, as an undergraduate student of physics in IUT (Isfahan University of Technology) I had the opportunity to learn the basics of modern physics from two of the best professors Drs. Mojtaba Mahzoon and Mehdi Barezi. Soon after in the University of Isfahan, I started research in theoretical physics for my Master studies. At the first year a famous researcher of particle physics joined Physics department of the University of Isfahan. My journey into the world of quantum field theory and gravity started with the courses he lectured for graduate students and this has led me to become his first student. Prof. Bijan Sheikholeslami is a known physicist for his works mostly on Sheikholeslami-Wohlert (SW or clover) action in lattice gauge theory and his 1986 paper on this so far has received over than 700 citations according SLAC SPIRES data. My last four years were the most relevant years to the contents of this thesis. During this time I enjoyed being the student of one the pioneers of the theory of Loop Quantum Gravity, Prof. Lee Smolin. Lee was the first person who welcomed me in Waterloo and the second person who became excited each time I received a new result. I also would like to thank Fotini Markopoulou for collaboration on one project which was a turning point for me on doing science throughout modeling, and all of her supports and long term discussions about her unique way of looking into quantum gravity. I also would like to thank Ab
The Role of Gravity in the Wave Function of Macroscopic Systems
Physics Essays, 1993
Some interpretation questions concerning a previous model put forward by the authors [Il Nuovo Cimento B 107, 211 (1992)] are elaborated here. In that model we obtained a breakdown of the quantum superposition principle when applied to macroscopic systems. The model is based on the concept of 'blurry metric', which we explain here. This concept is introduced through the "criterion of quantum objectivity" -exhaustivity of the wave function and objective probability in the measurements- and set in the framework of the conceptual problems of Quantum Mechanics. Other topics such as measurement, irreversibility, etc, are also analyzed.
But for now, the focus over the next few decades is on determining whether gravity is a quantum phenomenon. [12] Two teams of researchers working independently of one another have come up with an experiment designed to prove that gravity and quantum mechanics can be reconciled. [11] Bose, Marletto and their colleagues believe their proposals constitute an improvement on Feynman's idea. They are based on testing whether the mass could be entangled with a second identical mass via the gravitational field. [10]