We show that it is possible to explain the quantum measurement process within the framework of quantum mechanics without any additional postulates. The key concept of the theory is decoherence, which appears as an inherent characteristic of quantum mechanics and results from the uncertainty relation. In contrast to environment-induced decoherence, this decoherence exists prior to a measurement being made. To clarify our idea, we examine three elemental experiments: a Stern-Gerlach-like experiment, the Einstein-Podolsky-Rosen-Bohm (EPR-Bohm) experiment, and the double-slit experiment. By considering the first experiment, we explain how the uncertainty relation between position and momentum introduces decoherence prior to measurement. Consideration of the EPR-Bohm experiment leads us to conclude that the correlation of the EPR pair is not a consequence of what is known as the collapse of the wave function. Our theory of decoherence can also be applied to experiments with continuous eigenvalues, such as the double-slit experiment. Consideration of the double-slit experiment leads us to understand how pure quantum mechanics describes the fact that quanta behave as interfering particles.We show that it is possible to explain the quantum measurement process within the framework of quantum mechanics without any additional postulates. The key concept of the theory is decoherence, which appears as an inherent characteristic of quantum mechanics and results from the uncertainty relation. In contrast to environment-induced decoherence, this decoherence exists prior to a measurement being made. To clarify our idea, we examine three elemental experiments: a Stern-Gerlach-like experiment, the Einstein-Podolsky-Rosen-Bohm (EPR-Bohm) experiment, and the double-slit experiment. By considering the first experiment, we explain how the uncertainty relation between position and momentum introduces decoherence prior to measurement. Consideration of the EPR-Bohm experiment leads us to conclude that the correlation of the EPR pair is not a consequence of what is known as the collapse of the wave function. Our theory of decoherence can also be applied to experiments with continuous eigenvalues, such as the double-slit experiment. Consideration of the double-slit experiment leads us to understand how pure quantum mechanics describes the fact that quanta behave as interfering particles.

Apr 12, 20170 citations

Environment-induced decoherence

WORLD SCIENTIFIC eBooksOct 8, 20181 citation

Can the environment-induced decoherence solve the measurement problem?

Kayoko Awaya

Vistas in AstronomyJan 1, 19930 citations

Decoherence and Schrödinger-cat states in a Stern-Gerlach-type experiment

Anu Venugopalan

A Stern-Gerlach setup for the measurement on a quantum system (spin-$$ $\frac{1}{2}$ ) with a macroscopic quantum apparatus (the particle trajectory) produces a Schr\"odinger-cat-like superposition in which the spin states correlate with wave packets centered around macroscopically distinguishable positions and momenta. When an interaction with an environment is included, the pure density matrix of the system-apparatus combination reduces to a statistical mixture in the spin space, and exact solutions show that the decoherence time for this reduction goes inversly as the macroscopic separation between the two parts of the superposition correlating with up- and down-spin states. This is consistent with Zurek's approximate result for the decoherence time, and the persistence of system-meter correlations at large times makes it an interesting candidate to look at experimentally.A Stern-Gerlach setup for the measurement on a quantum system (spin-$$$\frac{1}{2}$) with a macroscopic quantum apparatus (the particle trajectory) produces a Schr\"odinger-cat-like superposition in which the spin states correlate with wave packets centered around macroscopically distinguishable positions and momenta. When an interaction with an environment is included, the pure density matrix of the system-apparatus combination reduces to a statistical mixture in the spin space, and exact solutions show that the decoherence time for this reduction goes inversly as the macroscopic separation between the two parts of the superposition correlating with up- and down-spin states. This is consistent with Zurek's approximate result for the decoherence time, and the persistence of system-meter correlations at large times makes it an interesting candidate to look at experimentally.

Physical Review ANov 1, 199719 citations

QED-Induced Spin Dynamics and Decoherence in the Stern–Gerlach Experiment

César Augusto Dartora

Jan 1, 20250 citations

Decoherence Through Interaction with the Environment

Erich Joos

Springer eBooksJan 1, 200329 citations

A Stern-Gerlach setup for the measurement on a quantum system (spin-$$

\frac{1}{2}

) with a macroscopic quantum apparatus (the particle trajectory) produces a Schr\"odinger-cat-like superposition in which the spin states correlate with wave packets centered around macroscopically distinguishable positions and momenta. When an interaction with an environment is included, the pure density matrix of the system-apparatus combination reduces to a statistical mixture in the spin space, and exact solutions show that the decoherence time for this reduction goes inversly as the macroscopic separation between the two parts of the superposition correlating with up- and down-spin states. This is consistent with Zurek's approximate result for the decoherence time, and the persistence of system-meter correlations at large times makes it an interesting candidate to look at experimentally.