Researchers discovered elusive half-quantum vortices in a superfluid

December 14, 2016
A half-quantum vortex combines circular spin flow and circular mass flow, leading to the formation of vortex pairs that can be observed experimentally. Credit: Credit: Ella Maru Studio

Researchers have discovered half-quantum vortices in superfluid helium. This vortex is a topological defect, exhibited in superfluids and superconductors, which carries a fixed amount of circulating current. These objects originally predicted to exist in superfluid helium in 1976. The discovery will provide access to the cores of half-quantum vortices, hosting isolated Majorana modes, exotic solitary particles. Understanding these modes is essential for the progress of quantum information processing, building a quantum computer.

Researchers in Aalto University, Finland, and P.L. Kapitza Institute in Moscow have discovered half-quantum vortices in . This vortex is a topological defect, exhibited in superfluids and superconductors, which carries a fixed amount of circulating current.

"This discovery of half-quantum vortices culminates a long search for these objects originally predicted to exist in superfluid helium in 1976," says Samuli Autti, Doctoral Candidate at Aalto University in Finland.

"In the future, our discovery will provide access to the cores of half-quantum vortices, hosting isolated Majorana modes, exotic solitary particles. Understanding these modes is essential for the progress of , building a quantum computer," Autti continues.

Macroscopic coherence in quantum systems such as superfluids and superconductors provides many possibilities, and some central limitations. For instance, the strength of circulating currents in these systems is limited to certain discrete values by the laws of quantum mechanics. A half-quantum vortex overcomes that limitation using the non-trivial topology of the underlying material, a topic directly related to the 2016 Nobel Prize in physics.

The experiments were carried out using the rotating cryostat in the Low Temperature Laboratory at Aalto University, Finland. Credit: Mikko Raskinen/Aalto University

Among the emerging properties is one analogous to the so-called Alice string in high-energy physics, where a particle on a route around the string flips the sign of its charge. In general the quantum character of these systems is already utilized in ultra-sensitive SQUID amplifiers and other important quantum devices.

The article Observation of Half-Quantum Vortices in Topological Superfluid 3He has been published today in the online version of Physical Review Letters. Experiments were done in the Low Temperature Laboratory at Aalto University.

Samuli Autti with the rotating cryostat in the Low Temperature Laboratory at Aalto University, Finland. Credit: Alexander Savin/Aalto University

Explore further: Physicists manipulate Abrikosov vortices

More information: Physical Review Letters, DOI: 10.1103/PhysRevLett.117.255301

Related Stories

Physicists manipulate Abrikosov vortices

November 28, 2016

A nanophotonics group led by Prof. Brahim Lounis of the University of Bordeaux, including scientists from MIPT, has performed a unique experiment involving the optical manipulation of individual Abrikosov vortices in a superconductor. ...

Using laser light to cool a quantum liquid

April 5, 2016

Australian researchers from The University of Queensland have, for the first time, used laser light to cool a special form of quantum liquid, called a superfluid.

Quantum particles form droplets

November 28, 2016

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: the atoms form a new type of quantum liquid or quantum droplet state. These so called quantum ...

Scientists discover particles similar to Majorana fermions

October 25, 2016

Majorana fermions were first proposed by the physicist Ettore Majorana in 1937. They are fermion particles that are also their own antiparticles. These fermions are vital to the research of superconducting materials and topological ...

Recommended for you

Studying the quantum vacuum: Traffic jam in empty space

January 18, 2017

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by Professor Alfred Leitenstorfer has now shown how to manipulate the ...

Flexible ferroelectrics bring two material worlds together

January 17, 2017

Until recently, "flexible ferroelectrics" could have been thought of as the same type of oxymoronic phrase. However, thanks to a new discovery by the U.S. Department of Energy's (DOE) Argonne National Laboratory in collaboration ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.