scholarly journals Nonvacuum initial states for cosmological perturbations of quantum-mechanical origin

2000 ◽  
Vol 61 (8) ◽  
Author(s):  
Jérôme Martin ◽  
Alain Riazuelo ◽  
Mairi Sakellariadou
Keyword(s):  
Quantum Mechanical ◽  
Cosmological Perturbations ◽  
Initial States

scholarly journals Quantum-to-classical transition of cosmological perturbations for non-vacuum initial states

1997 ◽  
Vol 497 (1-2) ◽  
pp. 479-508 ◽  
Author(s):  
J. Lesgourgues ◽  
David Polarski ◽  
A.A. Starobinsky
Keyword(s):  
Cosmological Perturbations ◽  
Classical Transition ◽  
Initial States

Constructing deterministic models for quantum mechanical systems

2020 ◽  
Vol 17 (supp01) ◽  
pp. 2040007
Author(s):  
Gerard ’t Hooft
Keyword(s):  
Quantum Mechanics ◽  
Essential Element ◽  
Quantum Mechanical ◽  
Interpretation Of Quantum Mechanics ◽  
Final States ◽  
Deterministic Models ◽  
Quantum Theories ◽  
Initial States ◽  
Quantum Mechanical Systems ◽  
Entire Theory

A sharper formulation is presented for an interpretation of quantum mechanics advocated by the author. We claim that only those quantum theories should be considered for which an ontological basis can be constructed. In terms of this basis, the entire theory can be considered as being deterministic. An example is illustrated: massless, noninteracting fermions are ontological. Subsequently, as an essential element of the deterministic interpretation, we put forward conservation laws concerning the ontological nature of a variable, and the uncertainties concerning the realization of states. Quantum mechanics can then be treated as a device that combines statistics with mechanical, deterministic laws, such that uncertainties are passed on from initial states to final states.

Feedback control for communication with non-orthogonal states

2007 ◽  
Vol 7 (1&2) ◽  
pp. 127-138
Author(s):  
K. Jacobs
Keyword(s):  
Feedback Control ◽  
Quantum System ◽  
Continuous Measurement ◽  
Information Gain ◽  
Quantum Mechanical ◽  
Optimal Measurement ◽  
Classical Information ◽  
Long Time ◽  
Initial Preparation ◽  
Initial States

Communicating classical information with a quantum system involves the receiver making a measurement on the system so as to distinguish as well as possible the alphabet of states used by the sender. We consider the situation in which this measurement takes an appreciable time. In this case the measurement must be described by a continuous measurement process. We consider a continuous implementation of the optimal measurement for distinguishing between two non-orthogonal states, and show that feedback control can be used during this measurement to increase the rate at which the information regarding the initial preparation is obtained. We show that while the maximum obtainable increase is modest, the effect is purely quantum mechanical in the sense that the enhancement is only possible when the initial states are non-orthogonal. We find further that the enhancement in the rate of information gain is achieved at the expense of reducing the total information which the measurement can extract in the long-time limit.

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