Revealing a Pauli Crystal
January 13, 2021•
Physics 14, 5
A novel, high-resolution fluorescence imaging technique reveals a pattern, known as a Pauli crystal, that can emerge in a cloud of trapped, noninteracting fermions.
Figure 1: As a consequence of the Pauli exclusion principle, a few fermions trapped by lasers self-organize into a periodic structure called a Pauli crystal. By combining single-particle snapshots of the system, Marvin Holton and colleagues measure the multiparticle correlations that reveal the formation of a Pauli crystal.As a consequence of the Pauli exclusion principle, a few fermions trapped by lasers self-organize into a periodic structure called a Pauli crystal. By combining single-particle snapshots of the system, Marvin Holton and colleagues measure the multipa. Show more
Quantum Experiment Reveals Particles Can Form Collectives Out of Almost Nothing
18 DECEMBER 2020
How many particles do you need before individual atoms start behaving collectively? According to new research, the number is incredibly low. As few as six atoms will start transitioning into a macroscopic system, under the right conditions.
Using a specially designed ultra-cold laser trap, physicists observed the quantum precursor of the transition from a normal to a superfluid phase – offering a way to study the emergence of collective atomic behaviour and the limits of macroscopic systems.
Many-body physics is the field that seeks to describe and understand the collective behaviour of large numbers of particles: a bucket of water, for example, or a canister of gas. We can describe these substances in terms of their density, or their temperature – the way the substance is acting as a whole.
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Credit: Jonas Ahlstedt / Lund University Bioimaging Centre (LBIC)
Phase transitions describe dramatic changes in properties of a macroscopic system - like the transition from a liquid to a gas. Starting from individual ultracold atoms, Heidelberg University physicists were able to observe the emergence of such a transition with an increasing number of particles. The research work was carried out in the field of quantum physics under the direction of Prof. Dr Selim Jochim from the Institute for Physics.
In order to formulate effective theories in physics, microscopic details are set aside in favour of macroscopically observable quantities. A cup of water can be described by properties like pressure, temperature and density of the fluid, whereas the position and velocity of the individual water molecules are irrelevant. A phase transition describes the change of a macroscopic system from one state of matter, like fluid, to a different state of matter, like gaseous. The prop
Physicists observe the emergence of collective behaviour phys.org - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from phys.org Daily Mail and Mail on Sunday newspapers.