The Theory of Quantum Uncertainties and Quantum Measurements (original) (raw)
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MEASUREMENT IN QUANTUM PHYSICS
International Journal of Modern Physics E, 1999
The conceptual problems in quantum mechanics -related to the collapse of the wave function, the particle-wave duality, the meaning of measurement -arise from the need to ascribe particle character to the wave function. As will be shown, all these problems dissolve when working instead with quantum fields, which have both wave and particle character. Otherwise the predictions of quantum physics, including Bell's inequalities, coincide with those of the conventional treatments. The transfer of the results of the quantum measurement to the classical realm is also discussed.
2005
Quantum mechanics is not something you would have guessed. The moment you juxtapose quantum mechanics and everyday experience, the mysteries of how the former relates to, much less explains, the latter seem to have no end. Scientists are predisposed to take the obviousness of the world for granted (rightfully so) while trying to explain and justify quantum mechanics. Many philosophers also take the obviousness of the world for granted (improperly so). But there are a few philosophers who have taken note that the very obviousness of the world is rather surprising. It's surprising because that which is so obvious is at the same time so unobtrusive; it is so obvious it practically insists that we overlook it. Why does the world already make sense to us, at least in an unreflective way, the moment we turn our attention to it, before we've had a chance to formulate the first question about it? The child contends with and utilizes gravity long before its unceasing effects arouse curiosity. Upon a moment's reflection, we can see that our first tentative intellectual steps toward understanding, like learning our first musical tune, are already upheld by a robust commitment to the consistency and congruity of sensuous experience. We enter the world with a basic commitment to the world, what Merleau-Ponty called "perceptual faith."
One unorthodox view of the Heisenberg uncertainty principle (english)
It has long been clear, that human's ideas about the structure of surrounds him world are correspond to its world only partly. This truth is banal, but only recognition of this fact today is not sufficient. It appears that it's time to make the next step in scientific knowledge and to try to create (once again!) The New Model of the World which is to near understanding of the World as it is.
Preparation and measurement: two independent sources of uncertainty in quantum mechanics
1999
In the Copenhagen interpretation the Heisenberg uncertainty relation is interpreted as the mathematical expression of the concept of complementarity, quantifying the mutual disturbance necessarily taking place in a simultaneous or joint measurement of incompatible observables. This interpretation has already been criticized by Ballentine a long time ago, and has recently been challenged in an experimental way. These criticisms can be substantiated by using the generalized formalism of positive operator-valued measures, from which a new inequality can be derived, precisely illustrating the Copenhagen concept of complementarity. The different roles of preparation and measurement in creating uncertainty in quantum mechanics are discussed.
The measurement problem in quantum mechanics
2019
In this paper, we discuss the importance of measurement in quantum mechanics and the so-called measurement problem. Any quantum system can be described as a linear combination of eigenstates of an operator representing a physical quantity; this means that the system can be in a superposition of states that corresponds to different eigenvalues, i.e., different physical outcomes, each one incompatible with the others. The measurement process converts a state of superposition (not macroscopically defined) in a well-defined state. We show that, if we describe the measurement by the standard laws of quantum mechanics, the system would preserve its state of superposition even on a macroscopic scale. Since this is not the case, we assume that a measurement does not obey to standard quantum mechanics, but to a new set of laws that form a “quantum measurement theory”.
Fortschritte Der Physik-progress of Physics, 2003
Common misconceptions on the Heisenberg principle are reviewed, and the original spirit of the principle is reestablished in terms of the trade-off between information retrieved by a measurement and disturbance on the measured system. After analyzing the possibility of probabilistically reversible measurements, along with erasure of information and undoing of disturbance, general information-disturbance trade-offs are presented, where the disturbance of the measurement is related to the possibility in principle of undoing its effect. *
“No Information Without Disturbance”: Quantum Limitations of Measurement
Quantum Reality, Relativistic Causality, and Closing the Epistemic Circle (eds. W.C. Myrvold, J. Christian), pp. 229-256, 2009
In this contribution I review rigorous formulations of a variety of limitations of measurability in quantum mechanics. To this end I begin with a brief presentation of the conceptual tools of modern measurement theory. I will make precise the notion that quantum measurements necessarily alter the system under investigation and elucidate its connection with the complementarity and uncertainty principles.
Measurement and Fundamental Processes in Quantum Mechanics
In the standard mathematical formulation of quantum mechanics, measurement is an additional, exceptional fundamental process rather than an often complex, but ordinary process which happens also to serve a particular epistemic function: During a measurement of one of its properties which is not already determined by a preceding measure- ment, a measured system, even if closed, is taken to change its state discontinuously rather than continuously as is usual. Many, includ- ing Bell, have been concerned about the fundamental role thus given to measurement in the foundation of the theory. Others, including the early Bohr and Schwinger, have suggested that quantum mechan- ics naturally incorporates the unavoidable uncontrollable disturbance of physical state that accompanies any local measurement without the need for an exceptional fundamental process or a special measurement theory. Disturbance is unanalyzable for Bohr, but for Schwinger it is due to physical interactions’ being borne by fundamental particles having discrete properties and behavior which is beyond physical con- trol. Here, Schwinger’s approach is distinguished from more well known treatments of measurement, with the conclusion that, unlike most, it does not suffer under Bell’s critique of quantum measurement. Finally, Schwinger’s critique of measurement theory is explicated as a call for a deeper investigation of measurement processes that requires the use of a theory of quantum fields.
Interpretations of Quantum Mechanics and the measurement problem
2010
We present a panoramic view on various attempts to "solve" the problems of quantum measurement and macro-objectivation, i.e. of the transition from a probabilistic quantum mechanic microscopic world to a deterministic classical macroscopic world.