scholarly journals Inconsistency of a Realistic Interpretation of Quantum Measurements: a Simple Example

2020 ◽  
Vol 50 (4) ◽  
pp. 438-441
Author(s):  
Pablo L. Saldanha
Keyword(s):  
Quantum Measurements ◽  
Realistic Interpretation

scholarly journals Quantum Euler Relation for Local Measurements

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 889
Author(s):  
Akram Touil ◽  
Kevin Weber ◽  
Sebastian Deffner
Keyword(s):  
Quantum Systems ◽  
Quantum Measurements ◽  
Weak Coupling Regime ◽  
Local Quantum ◽  
Dissipation Model ◽  
Local Measurements ◽  
Euler Relation ◽  
Quantum Analog ◽  
Back Action ◽  
Classical Thermodynamics

In classical thermodynamics the Euler relation is an expression for the internal energy as a sum of the products of canonical pairs of extensive and intensive variables. For quantum systems the situation is more intricate, since one has to account for the effects of the measurement back action. To this end, we derive a quantum analog of the Euler relation, which is governed by the information retrieved by local quantum measurements. The validity of the relation is demonstrated for the collective dissipation model, where we find that thermodynamic behavior is exhibited in the weak-coupling regime.

scholarly journals Measuring coherence of quantum measurements

2019 ◽  
Vol 1 (3) ◽  
Author(s):  
Valeria Cimini ◽  
Ilaria Gianani ◽  
Marco Sbroscia ◽  
Jan Sperling ◽  
Marco Barbieri
Keyword(s):  
Quantum Measurements

scholarly journals QUANTUM MEASUREMENTS, INFORMATION AND ENTROPY PRODUCTION

1999 ◽  
Vol 13 (28) ◽  
pp. 3369-3382 ◽  
Author(s):  
Y. N. SRIVASTAVA ◽  
G. VITIELLO ◽  
A. WIDOM
Keyword(s):  
Entropy Production ◽  
Information Entropy ◽  
Quantum Measurements ◽  
Second Law ◽  
Quantum Object ◽  
Measurement Apparatus ◽  
Thermodynamic Entropy ◽  
Classical Measurement ◽  
The Relationship

In order to understand the Landau–Lifshitz conjecture on the relationship between quantum measurements and the thermodynamic second law, we discuss the notion of "diabatic" and "adiabatic" forces exerted by the quantum object on the classical measurement apparatus. The notion of heat and work in measurements is made manifest in this approach and the relationship between information entropy and thermodynamic entropy is explored.

scholarly journals Decoherence and its role in the modern measurement problem

2012 ◽  
Vol 370 (1975) ◽  
pp. 4576-4593 ◽  
Author(s):  
David Wallace
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Quantum Measurement ◽  
Measurement Problem ◽  
Scientific Practice ◽  
Measurement Theory ◽  
Quantum Measurements ◽  
Quantum Measurement Problem ◽  
Modern Physics ◽  
Conceptual Problems

Decoherence is widely felt to have something to do with the quantum measurement problem, but getting clear on just what is made difficult by the fact that the ‘measurement problem’, as traditionally presented in foundational and philosophical discussions, has become somewhat disconnected from the conceptual problems posed by real physics. This, in turn, is because quantum mechanics as discussed in textbooks and in foundational discussions has become somewhat removed from scientific practice, especially where the analysis of measurement is concerned. This paper has two goals: firstly (§§1–2), to present an account of how quantum measurements are actually dealt with in modern physics (hint: it does not involve a collapse of the wave function) and to state the measurement problem from the perspective of that account; and secondly (§§3–4), to clarify what role decoherence plays in modern measurement theory and what effect it has on the various strategies that have been proposed to solve the measurement problem.

scholarly journals Contextual Values of Observables in Quantum Measurements

2010 ◽  
Vol 104 (24) ◽  
Author(s):  
J. Dressel ◽  
S. Agarwal ◽  
A. N. Jordan
Keyword(s):  
Quantum Measurements ◽  
Contextual Values

Optimal quantum measurements for spin-1 and spin-3/2 particles

2001 ◽  
Vol 1 (3) ◽  
pp. 52-61
Author(s):  
P Aravind
Keyword(s):  
Positive Operator ◽  
Pure State ◽  
Quantum Measurements ◽  
Positive Operator Valued Measures ◽  
Unknown State

Positive operator valued measures (POVMs) are presented that allow an unknown pure state of a spin-1 particle to be determined with optimal fidelity when 2 to 5 copies of that state are available. Optimal POVMs are also presented for a spin-3/2 particle when 2 or 3 copies of the unknown state are available. Although these POVMs are optimal they are not always minimal, indicating that there is room for improvement.

Predictions of Endwall Losses and Secondary Flows in Axial Flow Turbine Cascades

1987 ◽  
Vol 109 (2) ◽  
pp. 229-236 ◽  
Author(s):  
O. P. Sharma ◽  
T. L. Butler
Keyword(s):  
Flow Visualization ◽  
Secondary Flow ◽  
Axial Flow ◽  
Secondary Flows ◽  
Integral Boundary ◽  
Realistic Interpretation ◽  
Proposed Model ◽  
Flow Theories ◽  
Semi Empirical ◽  
End Wall

This paper describes the development of a semi-empirical model for estimating end-wall losses. The model has been developed from improved understanding of complex endwall secondary flows, acquired through review of flow visualization and pressure loss data for axial flow turbomachine cascades. The flow visualization data together with detailed measurements of viscous flow development through cascades have permitted more realistic interpretation of the classical secondary flow theories for axial turbomachine cascades. The re-interpreted secondary flow theories together with integral boundary layer concepts are used to formulate a calculation procedure for predicting losses due to the endwall secondary flows. The proposed model is evaluated against data from published literature and improved agreement between the data and predictions is demonstrated.

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