14. Mai 2021

Roton Excitations in an Oblate Dipolar Quantum Gas

Our recent measurements of angular and radial roton modes in dipolar Bose-Einstein condensates are featured on the cover of Physical Review Letters

A detailed study of the elementary excitations of a complex quantum system can reveal hidden internal properties. We have studied the so-called roton excitations and their role in the phase transition from a dipolar Bose-Einstein condensate to a supersolid or a droplet crystal. A supersolid is an elusive state of matter that allows for superfluid flow despite its crystalline order.

Roton excitations were historically introduced by Landau to explain the properties of superfluid liquid helium and can be seen as density waves with a finite wavelength whose energy reduces as a precursor of a crystallization transition. In dipolar BECs/quantum gases the roton excitation has so far exclusively been studied in elongated quasi one-dimensional trapping geometries where it is the origin of the crystallization to a so-called dipolar supersolid [Phys. Rev. X 11, 011037 (2021) and Phys. Rev. Lett. 112, 183401 (2019)]. In our recent study we focus on the crystallization mechanisms in a cylindrically symmetric oblate trapping configuration extending the previous studies to two dimensions.

In these oblate geometries we now find two kinds of roton excitations namely radial and angular roton modes, of which the angular roton modes feature a particular symmetry that defines the symmetry of the formed droplet crystal or a two dimensional supersolid.

Read the full paper “Roton Excitations in an Oblate Dipolar Quantum Gas”


März 2021

Februar 2021

Januar 2021

September 2020

Juni 2020

April 2020

März 2020

Februar 2020

Dezember 2019

November 2019

September 2019

August 2019

Juli 2019

Juni 2019

April 2019

März 2019

Februar 2019

Januar 2019

November 2018

Oktober 2018

Mai 2018

März 2018

Februar 2018

Januar 2018

Dezember 2017

Juli 2017

März 2017

Februar 2017

November 2016

Mai 2015

Zum Seitenanfang