A team of physicists was able to observe in an experiment how the anisotropic properties of particles distort the Fermi surface in a quantum gas. The study provides the basis for future research into how the geometry of particle interactions may affect the properties of a quantum system.
[Translation by Dr. Nachmani Moshe]
A team of physicists was able to observe in an experiment how the anisotropic properties of particles distort the Fermi surface in a quantum gas. The study provides the basis for future research into how the geometry of particle interactions may affect
On the properties of a quantum system.
A team of physicists from Austria, led by researcher Francesca Ferlaino, was able to observe in an experiment how the anisotropic properties (different physical properties in different planes) of particles distort the Fermi surface in a quantum gas. The study has long been published in the prestigious scientific journal Science.
The behavior of a system is determined by the characteristics of its interactions. An important concept in solid state physics in describing the energy distribution of electrons in solids is a Fermi surface (Wikipedia), named after the Italian physicist Enrico Fermi. The existence of a Fermi surface is a direct consequence of the Pauli Forbidden Principle (Wikipedia) which states that two fermions cannot be in the same quantum state at the same time. Energetically, a Fermi surface distinguishes between filled and empty energy levels. For electrons and other fermionic particles with isotropic interactions - that is, identical properties in all directions - a Fermi surface is spherical. "This is the normal state in nature and is the basis for many physical phenomena," explains the lead researcher from the University of Innsbruck. "When the interaction of the particle is anisotropic - that is, direction-dependent - the physical behavior of the system changes completely. The introduction of anisotropic interactions may distort the Fermi surface and we predict that an ellipsoidal structure will be obtained (oval-shaped, egg-like)." The distortion of a Fermi surface is caused by the force relationship between strong magnetic interactions and Pauli's forbidden principle. The research team was able to show in an experiment, for the first time ever, this kind of distortion.
As part of their experiment, the researchers confined a gas of fermionic erbium atoms in a laser trap and cooled the system to almost absolute zero. The element erbium is a strong magnetic element that induces bipolar behavior. The interactions between these atoms, therefore, are orientation dependent. When the researchers released the supercooled gas from its trap, they could infer the shape of a Fermi surface from the particle's momentum distribution. "Erbium atoms behave similarly to magnets, i.e. their interactions are closely dependent on the directionality of the particles. Our experiment proves that the shape of a Fermi surface depends on the geometry of the interactions and is no longer spherical," explains one of the researchers.
"The general question we addressed in our experiment was how the geometry of particle interactions affects the quantum properties of matter," explains the lead researcher. Answering this question is of great importance to physicists from different branches of physics, for example - in the study of high-temperature semiconductors. "We need to get a better understanding of these properties in order to develop innovative quantum systems," emphasizes the researcher. Systems of cold quantum gases, in particular, have once again proven their importance as an ideal tool for simulating quantum complex scenarios.
8 תגובות
Yossi, you don't see many comments because the article is written in Chinese. Not all surfers on this site are professors of quantum physics.
I am a student and work in industry. These are my study hours. Sorry.
Oops, for some reason I completely ignored Yossi, sorry Yossi... I can't see anything at this time.. Good night
The original article
http://arxiv.org/pdf/1405.2154.pdf
So few responses to an important article. The reaction creates a perfect non-spherical volumetric shape (ellipse) and this is evidence that a Fermi plane of the energy that separates conduction from insulation, approximately between free and bound charged particles (electrons?) as a quantum effect exists. The magnetic response of the gas is not symmetrical in space. The transition from an energy plane to a space plane goes through a Fourier transformation. Therefore I would like to see the original article. The Fourier transform acts like a lens on the three-dimensional energetic image and transfers it to the plane of time as we see a negative or infrared photograph of the image.
The article in its free version http://arxiv.org/pdf/1405.2154v2.pdf