PHYSICS / THERMODYNAMICS

LR-HIGHEST-CONFIRMED-ARTIFICIAL-NEGATIVE-ABSOLUTE-TEMPERATURE-SYSTEMOPEN LIMIT

First experimental realization of a negative absolute temperature quantum gas

Name: First experimental realization of a negative absolute temperature quantum gas
Creator: Limits Registry
Published: 2013-01-04T00:00:00.000Z
Keywords: PHYSICS / THERMODYNAMICS

Physicists at Ludwig Maximilian University of Munich created the first system with a negative absolute temperature in its motional degrees of freedom in 2013, using ultracold potassium-39 atoms in an optical lattice engineered so that higher-energy states were more populated than lower-energy ones — a counterintuitive state that is technically 'hotter' than infinite positive temperature, since heat flows from it into any positive-temperature system it contacts.

— page viewsSpecification version 1Published 2013-01-041 evidence records

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Description

Formal question

The first experimental demonstration of a genuine negative absolute (Kelvin-scale) temperature in a system's motional degrees of freedom, as opposed to the previously known negative-temperature spin systems.

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Primary sources

Science — Negative Absolute Temperature for Motional Degrees of Freedom — First experimental realization of a negative absolute temperature quantum gas Ludwig Maximilian University of Munich, Germany

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Best demonstrated value2013-01-04

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2026

CLM-HIGHEST-CONFIRMED-ARTIFICIAL-NEGATIVE-ABSOLUTE-TEMPERATURE-SYSTEM= 2013-01-04CONSTRUCTIONUltracold potassium atoms trapped in an optical lattice were manipulated using a rapid inversion of the trapping potential and magnetic field, flipping the energy-level population distribution to favor higher-energy states, verified via time-of-flight absorption imaging.Evidence quality: PAPER · Source: Science — Negative Absolute Temperature for Motional Degrees of Freedom — First experimental realization of a negative absolute temperature quantum gas ↗

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First experimental realization of a negative absolute temperature quantum gas

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First experimental realization of a negative absolute temperature quantum gas

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