Quantum simulation of quantum crystals

Date:
August 27, 2020
Source:
University of Freiburg
Summary:
A research team describes the new possibilities offered by the
use of ultracold dipolar atoms.



FULL STORY ==========================================================================
The quantum properties underlying crystal formation can be replicated
and investigated with the help of ultracold atoms. A team led by Dr. Axel
U. J.

Lode from the University of Freiburg's Institute of Physics has now
described in the journal Physical Review Letters how the use of dipolar
atoms enables even the realization and precise measurement of structures
that have not yet been observed in any material. The theoretical study was
a collaboration involving scientists from the University of Freiburg, the University of Vienna and the Technical University of Vienna in Austria,
and the Indian Institute of Technology in Kanpur, India.


========================================================================== Crystals are ubiquitous in nature. They are formed by many different
materials -- from mineral salts to heavy metals like bismuth. Their
structures emerge because a particular regular ordering of atoms or
molecules is favorable, because it requires the smallest amount of
energy. A cube with one constituent on each of its eight corners,
for instance, is a crystal structure that is very common in nature. A
crystal's structure determines many of its physical properties, such
as how well it conducts a current or heat or how it cracks and behaves
when it is illuminated by light. But what determines these crystal
structures? They emerge as a consequence of the quantum properties of
and the interactions between their constituents, which, however, are
often scientifically hard to understand and also hard measure.

To nevertheless get to the bottom of the quantum properties of the
formation of crystal structures, scientists can simulate the process
using Bose-Einstein condensates -- trapped ultracold atoms cooled down to temperatures close to absolute zero or minus 273.15 degrees Celsius. The
atoms in these highly artificial and highly fragile systems are extremely
well under control. With careful tuning, the ultracold atoms behave
exactly as if they were the constituents forming a crystal. Although
building and running such a quantum simulator is a more demanding task
than just growing a crystal from a certain material, the method offers
two main advantages: First, scientists can tune the properties for the
quantum simulator almost at will, which is not possible for conventional crystals. Second, the standard readout of cold-atom quantum simulators
are images containing information about all crystal particles. For a conventional crystal, by contrast, only the exterior is visible, while
the interior -- and in particular its quantum properties -- is difficult
to observe.

The researchers from Freiburg, Vienna, and Kanpur describe in their study
that a quantum simulator for crystal formation is much more flexible
when it is built using ultracold dipolar quantum particles. Dipolar
quantum particles make it possible to realize and investigate not just conventional crystal structures, but also arrangements that were hitherto
not seen for any material.

The study explains how these crystal orders emerge from an intriguing competition between kinetic, potential, and interaction energy and how
the structures and properties of the resulting crystals can be gauged
in unprecedented detail.

The quantum properties underlying crystal formation can be replicated
and investigated with the help of ultracold atoms. A team led by Dr. Axel
U. J.

Lode from the University of Freiburg's Institute of Physics has now
described in the journal Physical Review Lettershow the use of dipolar
atoms enables even the realization and precise measurement of structures
that have not yet been observed in any material. The theoretical study was
a collaboration involving scientists from the University of Freiburg, the University of Vienna and the Technical University of Vienna in Austria,
and the Indian Institute of Technology in Kanpur, India.

Crystals are ubiquitous in nature. They are formed by many different
materials -- from mineral salts to heavy metals like bismuth. Their
structures emerge because a particular regular ordering of atoms or
molecules is favorable, because it requires the smallest amount of
energy. A cube with one constituent on each of its eight corners,
for instance, is a crystal structure that is very common in nature. A
crystal's structure determines many of its physical properties, such
as how well it conducts a current or heat or how it cracks and behaves
when it is illuminated by light. But what determines these crystal
structures? They emerge as a consequence of the quantum properties of
and the interactions between their constituents, which, however, are
often scientifically hard to understand and also hard measure.

To nevertheless get to the bottom of the quantum properties of the
formation of crystal structures, scientists can simulate the process
using Bose-Einstein condensates -- trapped ultracold atoms cooled down to temperatures close to absolute zero or minus 273.15 degrees Celsius. The
atoms in these highly artificial and highly fragile systems are extremely
well under control. With careful tuning, the ultracold atoms behave
exactly as if they were the constituents forming a crystal. Although
building and running such a quantum simulator is a more demanding task
than just growing a crystal from a certain material, the method offers
two main advantages: First, scientists can tune the properties for the
quantum simulator almost at will, which is not possible for conventional crystals. Second, the standard readout of cold-atom quantum simulators
are images containing information about all crystal particles. For a conventional crystal, by contrast, only the exterior is visible, while
the interior -- and in particular its quantum properties -- is difficult
to observe.

The researchers from Freiburg, Vienna, and Kanpur describe in their study
that a quantum simulator for crystal formation is much more flexible
when it is built using ultracold dipolar quantum particles. Dipolar
quantum particles make it possible to realize and investigate not just conventional crystal structures, but also arrangements that were hitherto
not seen for any material.

The study explains how these crystal orders emerge from an intriguing competition between kinetic, potential, and interaction energy and how
the structures and properties of the resulting crystals can be gauged
in unprecedented detail.


========================================================================== Story Source: Materials provided by University_of_Freiburg. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Budhaditya Chatterjee, Camille Le've^que, Jo"rg Schmiedmayer, Axel
U. J. Lode. Detecting One-Dimensional Dipolar Bosonic Crystal
Orders via Full Distribution Functions. Physical Review Letters,
2020; 125 (9) DOI: 10.1103/PhysRevLett.125.093602 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200827122112.htm

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