Vortices in atomic gases resolve basic phenomena of quantum physics

Quantum phenomena at extremely low temperatures are fervently studied both theoretically and experimentally in contemporary physics. Alkali atoms cooled to near absolute zero formed the first experimentally successful gaseous Bose–Einstein condensate in 1995. Six years later, the achievement was awarded…

Quantum phenomena at extremely low temperatures are fervently studied both theoretically and experimentally in contemporary physics. Alkali atoms cooled to near absolute zero formed the first experimentally successful gaseous Bose–Einstein condensate in 1995. Six years later, the achievement was awarded the Nobel Prize in Physics.

Pekko Kuopanportti has studied vortex structures appearing in Bose–Einstein condensates in his doctoral dissertation for the Aalto University Department of Applied Physics. The properties and behaviour of these vortices are not yet fully known.

“The vortices are quantised whirls in the currents of extremely dilute gases of alkali atoms. Even though my research methods are computational and analytical, all my results are also experimentally feasible.”

The atomic gases Kuopanportti has explored are 100 000 times thinner than air. To achieve the condensate, the alkali atoms must first be evaporated off from solid metal to form a gas, then cooled to near absolute zero and captured in a magneto-optical trap where they can be controlled. Kuopanportti has computationally analysed several novel vortex phenomena and theoretically verified previous experimental findings.
“In Bose–Einstein condensates all the particles of a system occupy the same quantum state. They form a collective superatom of a kind, and enable the study of basic quantum mechanical phenomena on a size scale almost observable to the eye.”
Unexplored giant vortices reveal the prospects of quantum gases
The condensate can be described with a complex wave function, as if it was a single quantum particle. The function has a complex phase whose windings represent the vortices appearing in the flow of the condensate atoms.
“The gas circulates around the vortex in the same way as water flows in a sink down the drain. Stable quantised vortices demonstrate that Bose–Einstein condensates are actually frictionless superfluids. For instance, if one tries to spin a condensate, a regular lattice of quantised vortices emerges, as the superfluid tries to imitate an ordinary fluid.”
Increasing the number of phase windings around a vortex results in a multiply quantised, or giant, vortex. Kuopanportti tells that already in 2007 his colleagues at the Department of Applied Physics theoretically proposed a vortex pump, an experimental method to create giant vortices in magnetically trapped condensates. The pump might help to discover how large the giant vortices can get before they become too unstable and short-lived to be studied at all.
Kuopanportti has now analysed the properties of giant vortices and the practical limits of the vortex pump.
“Giant vortices tend to split into single-quantum vortices. I have analysed how they break down, and what mechanisms lead to the splitting. So far only vortices with quantum numbers below 10 have been studied; I have systematically proceeded to 100.”
“Now that I have theoretically explored the properties of giant vortices, it would not take much from experimental groups to realise them. My work also contributes to the future development of the vortex pump: the behaviour of giant vortices can now be predicted and their breakdown prevented.”
Condensates as memory devices for quantum computers?
Kuopanportti works in the Aalto University National Centre of Excellence in Computational Nanoscience. His group Quantum Computing and Devices also studies the prerequisites for quantum computing. This year’s Nobel Prize in Physics was recently awarded to experimental research promoting the creation of quantum computers. Kuopanportti muses on the use of Bose–Einstein condensates in quantum computing.
“They could be used as the memory device of quantum computers. Condensates live for minutes, significantly longer than photon-based quantum bits that have a life span of microseconds. The condensates could work as a storage and retrieval repository for quantum information. However, experimental research in the field is still in its infancy.”

Provided by

Aalto University

view popular
send feedback to editors

4.3 /5 (3 votes)

1
2
3
4
5

Move the slider to adjust rank threshold, so that you can hide some of the comments.

Display comments:
newest first

Rank

1
2
3
4
5

4.3 /5 (3 votes)

more news

Related Stories

Sep 18, 2007
0
Jumping into the quantum whirlpool

Feb 21, 2005
0
Ultra-cold temperature physics opens way to understanding and applications

Mar 18, 2010
0
Discovery could pave the way for quantum computing

May 22, 2012
0
First Bose-Einstein condensate of erbium produced

Relevant PhysicsForums posts

momentum and collisions
51 minutes ago
if a hard sticky mud ball is trown on a wall it sticks to it
it is an inelastic collision
K.E. is not conserved
but here momentum is also not conserved because mud had an initial velocity
so…

Incident and reflected wave
4 hours ago
When my book derives equations for reflection between two media it simply says something like this:
Suppose a plane electromagnetic wave meets the boundary between two media. This gives rise to an…

Reason for two tides on Earth
8 hours ago
There was a thing that kept me wondering for several years, which no science teacher managed to explain. Why does gravitational pull of the Moon causes two tides on Earth at the same time? Would’nt…

How slow can electron go?
12 hours ago
Are we even able to accurately measure speed of electrons, in say electron beam or around atom nucleus, how?

Is it true electrons can be slowed down? And if so, then where can we observe the…

Air Hose & Valve – Maximum Nominal vs Shock Pressure
12 hours ago
Hey guys I’m designing an air cannon robot and I need your help determining what valves and hoses i need to get in terms of maximum pressure. Based on my research, the maximum pressure ratings for…

Extending hamiltons principle
14 hours ago
Hamiltons principle can be used to derive Lagrange’s equations IF our coordinates are independent. Thus you pretty much show that for independent coordinates Hamiltons principle is equivalent to…

More from Physics Forums – Classical Physics

More news stories

Integrated optical vortices on a chip (w/ Video)

An international research group led by scientists from the University of Bristol and the Universities of Glasgow (UK) and Sun Yat-sen and Fudan in China, have demonstrated integrated arrays of emitters of …

Physics / Quantum Physics

21 hours ago |
4.9 / 5 (7) |
4
|

NASA pursues atom optics to detect the imperceptible

(Phys.org)—A pioneering technology capable of atomic-level precision is now being developed to detect what so far has remained imperceptible: gravitational waves or ripples in space-time caused by cataclysmic …

Physics / General Physics

17 hours ago |
4.9 / 5 (9) |
5
|

Scientists study how mid-level noise burstsmaffect the concentration of arithmetic-solving test subjects

Noise can be distracting, especially to a person trying to concentrate on a difficult task. Studying annoying noises helps architects design better building environments and policy makers choose effective noise regulations. …

Physics / General Physics

17 hours ago |
5 / 5 (1) |
0

Helmet-to-helmet collisions: Scientists model how vibrations from football hits wobble the brain

It’s fall football season, when fight songs and shouted play calls fill stadiums across the country. Another less rousing sound sometimes accompanies football games: the sharp crack of helmet-to-helmet collisions. Hard collisions …

Physics / General Physics

17 hours ago |
not rated yet |
0

Taking the bite out of baseball bats

Miss hitting the “sweet spot” on a baseball bat and the resulting vibrations can zing your hands. Bat companies have tried for decades to reduce these painful shocks with limited success. But Daniel Russell, a professor in …

Physics / General Physics

17 hours ago |
not rated yet |
0

Self-assembling nanofilaments enhance drug delivery

(Phys.org)—While most nanoparticles under development as drug delivery vehicles are spheres, a growing body of research suggests that cylindrical nanoparticles would perform even better at the twin goal of surviving in …

Nanotechnology / Bio & Medicine
1 hour ago |
not rated yet |
0
|

First micro-structure atlas of the human brain completed

A European team of scientists have built the first atlas of white-matter microstructure in the human brain. The project’s final results have the potential to change the face of neuroscience and medicine over the coming decade.

Medicine & Health / Neuroscience
38 minutes ago |
not rated yet |
0

Sharp rise in children admitted to hospital with throat infections since 1999

The number of children admitted to hospital in England for acute throat infections increased by 76 per cent between 1999 and 2010, according to new research published today in Archives of Disease in Childhood.

Medicine & Health / Diseases, Conditions, Syndromes
36 minutes ago |
not rated yet |
0

Directing evolutionary changes

Since 1859, when Darwin’s classic work “On the Origin of Species” was published, we have known that populations change over the course of time. The ability to adapt to changing surroundings is the basis …

Biology / Biotechnology
34 minutes ago |
not rated yet |
0

Italian court blames benign brain tumor on phone

(AP)—Italy’s top court has ruled that a businessman developed a benign brain tumor because he held a cellphone to his ear for hours daily for his job and deserves worker’s compensation.

Technology / Other
29 minutes ago |
not rated yet |
0

Freezing eggs for fertility works, caution urged

(AP)—New U.S. guidelines say freezing human eggs for fertility can work—but they still urge caution for women hoping the technology will pause a ticking biological clock.

Medicine & Health / Obstetrics & gynaecology
29 minutes ago |
not rated yet |
0