Quantum Measurements and Decoherence

1. Front Matter

   Pages i-xvi

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2. Introduction

   1. Introduction

      • Michael B. Mensky

      Pages 1-12

3. The Nature of Quantum Measurements

   1. Front Matter

      Pages 13-13

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   2. The Physics behind Quantum Measurements

      • Michael B. Mensky

      Pages 15-47

   3. Measurement induced uncertainties

      • Michael B. Mensky

      Pages 49-75

4. Continuous Quantum Measurements: Theory

   1. Front Matter

      Pages 77-77

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   2. Continuous Quantum Measurements: The General Notion

      • Michael B. Mensky

      Pages 79-94

   3. Fuzzy Continuous Measurements: Phenomenology

      • Michael B. Mensky

      Pages 95-125

   4. Restricted Path Integrals: General Features

      • Michael B. Mensky

      Pages 127-142

5. Continuous Quantum Measurements: Applications

   1. Front Matter

      Pages 143-143

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   2. The Monitoring of Energy

      • Michael B. Mensky

      Pages 145-160

   3. Monitoring by a series of observations

      • Michael B. Mensky

      Pages 161-174

   4. The Quantum Zeno effect in a passive setup

      • Michael B. Mensky

      Pages 175-185

6. Conceptual Problems and Prospects

   1. Front Matter

      Pages 187-187

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   2. Restricted Path Integrals and the Philosophy of Quantum Mechanics

      • Michael B. Mensky

      Pages 189-197

   3. Conclusion: New Prospects

      • Michael B. Mensky

      Pages 199-200

7. Back Matter

   Pages 201-231

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Quantum measurement (Le., a measurement which is sufficiently precise for quantum effects to be essential) was always one of the most impor­ tant points in quantum mechanics because it most evidently revealed the difference between quantum and classical physics. Now quantum measure­ ment is again under active investigation, first of all because of the practical necessity of dealing with highly precise and complicated measurements. The nature of quantum measurement has become understood much bet­ ter during this new period of activity, the understanding being expressed by the concept of decoherence. This term means a physical process lead­ ing from a pure quantum state (wave function) of the system prior to the measurement to its state after the measurement which includes classical elements. More concretely, decoherence occurs as a result of the entangle­ ment of the measured system with its environment and results in the loss of phase relations between components of the wave function of the measured system. Decoherence is essentially nothing else than quantum measurement, but considered from the point of view of its physical mechanism and resolved in time. The present book is devoted to the two concepts of quantum measure­ ment and decoherence and to their interrelation, especially in the context of continuous quantum measurement.

• Probability theory
• Stochastic processes
• metaphysics
• quantum mechanics
• stochastic process

• P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow, Russia

  Michael B. Mensky

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