Topic: Physics

Professor Giovanni Barontini at the University of Birmingham created a laboratory 'mini universe' where time emerged naturally from the behavior of quantum particles. This experiment helps scientists understand how time works in the universe and could lead to new insights into quantum gravity.

Physicists have long wondered: what is time? Is it a fundamental feature of the universe, or does it emerge from the behavior of particles themselves? To answer this question, Professor Giovanni Barontini at the University of Birmingham created a tiny laboratory 'mini universe' where time emerged naturally without the need for a clock.

In his experiment, Professor Barontini used 24,000 ultracold atoms cooled to just a few billionths of a degree above absolute zero. These atoms were sealed inside an isolated system and separated by a thin barrier created with two laser beams of different frequencies. This produced two regions: an observed ('bright') region and an unobserved ('dark') region.

The bright region repeatedly expanded and contracted, resembling a simplified version of the Big Bang followed by a Big Crunch. Because the system was completely isolated, researchers could reconstruct the sequence of events using only information from inside the mini universe itself, without referring to any outside laboratory clock. The results showed that time could emerge from changes taking place within the quantum system rather than existing as an independent background that always moves forward.

The experiment revealed that 'time' arose from changes in the disorder (or spread) of the atoms as they moved between the bright and dark regions. This concept is called 'entropic time.' In the experiment, this form of time effectively moved forward when the particle distribution changed and came to a halt when it stopped changing.

The researchers also found that a version of the Schrödinger equation, the fundamental equation of quantum mechanics, can be expressed using entropic time. This means scientists can still predict how the 'probability cloud' of a quantum system evolves over time even when time is defined by internal changes rather than an external clock.

Why It Matters

Understanding time and its relationship to the universe is crucial for developing new technologies and theories in physics, which could have significant impacts on our daily lives. This experiment brings us closer to understanding how time works at a fundamental level and could lead to breakthroughs in fields like quantum gravity and cosmology.

Key Facts

• Professor Giovanni Barontini created a laboratory 'mini universe' with 24,000 ultracold atoms at the University of Birmingham.
• The experiment showed that time can emerge from changes within a quantum system rather than existing as an independent background.
• The concept of 'entropic time' was introduced to describe how time arises from changes in disorder or spread within the system.
• A version of the Schrödinger equation was expressed using entropic time, allowing scientists to predict the evolution of quantum systems over time.

Key Terms

Quantum System

A group of particles that behave according to the principles of quantum mechanics.

Entropic Time

Time that arises from changes in disorder or spread within a system, rather than existing as an independent background.

Schrödinger Equation

The fundamental equation of quantum mechanics that describes the evolution of a quantum system over time.

Implications

Understanding time and its relationship to the universe is crucial for developing new technologies and theories in physics, which could have significant impacts on our daily lives. This experiment brings us closer to understanding how time works at a fundamental level and could lead to breakthroughs in fields like quantum gravity and cosmology.