
The following is an extract from our Lost in Space-Time newsletter. Each month, we dive into fascinating ideas from around the universe. You can sign up for Lost in Space-Time here.
Exploring the concept of temperature can lead to surprising revelations, even for seasoned physicists. The seemingly simple notion of hot and cold has evolved over centuries, with ongoing advancements pushing the boundaries of our understanding, especially in the quantum realm.
While temperature is commonly associated with systems comprising numerous particles, the question of whether a single particle can possess temperature sparks intriguing discussions. In classical thermodynamics, temperature reflects the average energy of a system’s microscopic components in equilibrium, akin to particles distributed on an energy ladder according to their energy levels.
However, the quantum world introduces complexities that challenge traditional notions of temperature. Quantum systems with few particles exhibit unique behaviors, such as particles existing between energy levels and non-equilibrium states that resist settling. This poses a fundamental question: how do we define temperature in the quantum domain?
Physicists are now delving into the quantum nature of temperature, focusing on its functional aspects rather than its static definition. By considering heat flow in quantum systems and the interaction between different systems, researchers are redefining temperature’s role in predicting energy exchanges.
In quantum mechanics, the traditional rules of temperature, where energy flows from higher to lower energy levels, are challenged. Quantum systems can exhibit unconventional energy distributions, leading to the concept of dual temperatures that dictate the system’s ability to give or take energy. This innovative approach enables scientists to predict heat transfer, extract work, and drive processes like refrigeration and computation in quantum systems.
Ultimately, the exploration of temperature in quantum systems reveals a nuanced understanding where a single particle may indeed possess temperature, albeit in a dual form. This paradigm shift underscores the ongoing evolution of thermodynamics in the quantum realm, opening new avenues for research and discovery.
Topics:
- quantum physics/
- Lost in Space-Time

