Quantum mechanics is shaking up our understanding of the classical world. A team of Spanish researchers offers a new perspective on the link between quantum and classical.
The foundations of quantum mechanics are based on the Schrödinger equation, which describes the evolution of quantum systems. However, the transition between the quantum world and the classical world remains a mystery. This transition, often called “wave function collapse”, has been at the heart of scientific debates for decades.
The Copenhagen interpretation suggests that the wave function collapses to a defined state during a measurement. However, this view is challenged by alternative theories such as many worlds. The latter proposes that each measurement creates a branching of the Universe, where all possible outcomes coexist. Philipp Strasberg and his team from the Autonomous University of Barcelona explored this idea through numerical simulations. Their work, published in Physical Review Xshow that the effects ofinterference quantum disappear quickly large scale. This explains why we observe a stable classical world.
The researchers simulated the evolution of complex quantum systems, including up to 50,000 energy levels. Their results show that stable macroscopic structures, corresponding to “branches of the Universe”, emerge naturally without requiring specific initial conditions. This discovery reinforces the idea that the classical world is an inevitable consequence of quantum mechanics.
In connection with statistical mechanics, the team also observed that certain branches of the Universe lead to an increase in entropy, while others lead to its decrease. These branches could possess opposing arrows of time, opening new perspectives on the nature of time.
This work opens the way to a better understanding of the transition between the quantum and classical worlds. They suggest that the emergence of a structured and ordered world is a fundamental property of quantum mechanics, independent of microscopic details.
What is the wave function in quantum mechanics?
The wave function is a central concept in quantum mechanics. It describes the state of a quantum system and contains all the information necessary to predict the measurement results.
Mathematically, the wave function is a solution to the Schrödinger equation. It is often represented by the Greek letter psi (ψ) and depends on spatial coordinates and time.
The wave function allows you to calculate the probability of finding a particle in a given region. This probability is proportional to the square of the amplitude of the wave function, according to Born’s rule.
However, the exact nature of the wave function remains a matter of debate. Some interpretations view it as a real entity, while others view it as a mathematical tool.
How does many worlds theory explain the collapse of the wave function?
The theory of many worlds, proposed by Hugh Everett III, offers a alternative to the Copenhagen interpretation. It suggests that the wave function never collapses, but branches with each measurement.
In this vision, each possible outcome of a measurement corresponds to a parallel universe. Thus, all quantum states coexist in distinct branches of the Universe.
This theory eliminates the need for an observer to cause the wave function to collapse. It offers a deterministic vision of quantum mechanics, where each quantum event creates new realities.
Although attractive, this theory raises questions about the nature of these parallel universes and their observability. Recent work, like that of Strasberg, attempts to clarify these aspects.
