Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Stirring-up atomtronics in a quantum circuit: What's so 'super' about this superfluid

Cover of Nature highlighting this research, courtesy of Nature Press Office. Image credit, Edwards/JQI
Cover of Nature highlighting this research, courtesy of Nature Press Office.

Image credit, Edwards/JQI

Abstract:
Atomtronics is an emerging technology whereby physicists use ensembles of atoms to build analogs to electronic circuit elements. Modern electronics relies on utilizing the charge properties of the electron. Using lasers and magnetic fields, atomic systems can be engineered to have behavior analogous to that of electrons, making them an exciting platform for studying and generating alternatives to charge-based electronics.

Stirring-up atomtronics in a quantum circuit: What's so 'super' about this superfluid

College Park, MD | Posted on February 12th, 2014

Using a superfluid atomtronic circuit, JQI physicists, led by Gretchen Campbell, have demonstrated a tool that is critical to electronics: hysteresis. This is the first time that hysteresis has been observed in an ultracold atomic gas. This research is published in the February 13 issue of Nature magazine, whose cover features an artistic impression of the atomtronic system.

Lead author Stephen Eckel explains, "Hysteresis is ubiquitous in electronics. For example, this effect is used in writing information to hard drives as well as other memory devices. It's also used in certain types of sensors and in noise filters such as the Schmitt trigger." Here is an example demonstrating how this common trigger is employed to provide hysteresis. Consider an air-conditioning thermostat, which contains a switch to regulate a fan. The user sets a desired temperature. When the room air exceeds this temperature, a fan switches on to cool the room. When does the fan know to turn off? The fan actually brings the temperature lower to a different set-point before turning off. This mismatch between the turn-on and turn-off temperature set-points is an example of hysteresis and prevents fast switching of the fan, which would be highly inefficient.

In the above example, the hysteresis is programmed into the electronic circuit. In this research, physicists observed hysteresis that is an inherent natural property of a quantum fluid. 400,000 sodium atoms are cooled to condensation, forming a type of quantum matter called a Bose-Einstein condensate (BEC), which has a temperature around 0.000000100 Kelvin (0 Kelvin is absolute zero). The atoms reside in a doughnut-shaped trap that is only marginally bigger than a human red blood cell. A focused laser beam intersects the ring trap and is used to stir the quantum fluid around the ring.

While BECs are made from a dilute gas of atoms less dense than air, they have unusual collective properties, making them more like a fluid—or in this case, a superfluid. What does this mean? First discovered in liquid helium in 1937, this form of matter, under some conditions, can flow persistently, undeterred by friction. A consequence of this behavior is that the fluid flow or rotational velocity around the team's ring trap is quantized, meaning it can only spin at certain specific speeds. This is unlike a non-quantum (classical) system, where its rotation can vary continuously and the viscosity of the fluid plays a substantial role.

Because of the characteristic lack of viscosity in a superfluid, stirring this system induces drastically different behavior. Here, physicists stir the quantum fluid, yet the fluid does not speed up continuously. At a critical stir-rate the fluid jumps from having no rotation to rotating at a fixed velocity. The stable velocities are a multiple of a quantity that is determined by the trap size and the atomic mass.

This same laboratory has previously demonstrated persistent currents and this quantized velocity behavior in superfluid atomic gases. Now they have explored what happens when they try to stop the rotation, or reverse the system back to its initial velocity state. Without hysteresis, they could achieve this by reducing the stir-rate back below the critical value causing the rotation to cease. In fact, they observe that they have to go far below the critical stir-rate, and in some cases reverse the direction of stirring to see the fluid return to the lower quantum velocity state.

Controlling this hysteresis opens up new possibilities for building a practical atomtronic device. For instance, there are specialized superconducting electronic circuits that are precisely controlled by magnetic fields and in turn, small magnetic fields affect the behavior of the circuit itself. Thus, these devices, called SQuIDs (superconducting quantum interference devices), are used as magnetic field sensors. "Our current circuit is analogous to a specific kind of SQuID called an RF-SQuID", says Campbell. "In our atomtronic version of the SQuID, the focused laser beam induces rotation when the speed of the laser beam "spoon" hits a critical value. We can control where that transition occurs by varying the properties of the "spoon". Thus, the atomtronic circuit could be used as an inertial sensor."

This two-velocity state quantum system has the ingredients for making a qubit. However, this idea has some significant obstacles to overcome before it could be a viable choice. Atomtronics is a young technology and physicists are still trying to understand these systems and their potential. One current focus for Campbell's team includes exploring the properties and capabilities of the novel device by adding complexities such as a second ring.

###

This research was supported by the NSF Physics Frontier Center at JQI.

####

For more information, please click here

Contacts:
Gretchen Campbell

Copyright © Joint Quantum Institute

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

"Hysteresis in a quantized superfluid ‘atomtronic’ circuit," S. Eckel, J.G. Lee, F. Jendrzejewski, N. Murray, C.W. Clark, C.J. Lobb, W.D. Phillips, M. Edwards, G.K. Campbell, Nature, 506, 200 (2014):

"Driving Phase Slips in a Superfluid Atom Circuit with a Rotating Weak Link," K.C. Wright, R.B. Blakestad, C.J. Lobb, W.D. Phillips, G.K. Campbell, Phys. Rev. Lett., 110, 060504 (2013):

"Observation of Persistent Flow of a Bose-Einstein Condensate in a Toroidal Trap," C. Ryu, M.F. Andersen, P. Cladé, V. Natarajan, K. Helmerson, W.D. Phillips, Phys. Rev. Lett., 99, (2007):

VIDEO: This is an animation showing a laser beam stirring a ring shaped quantum gas:

Related News Press

News and information

Stanford breakthrough heralds super-efficient light-based computers: Light can transmit more data while consuming far less power than electricity, and an engineering feat brings optical data transport closer to replacing wires May 29th, 2015

Donuts, math, and superdense teleportation of quantum information May 29th, 2015

OSU researchers prove magnetism can control heat, sound: Team leverages OSC services to help confirm, interpret experimental findings May 29th, 2015

Physics

Donuts, math, and superdense teleportation of quantum information May 29th, 2015

OSU researchers prove magnetism can control heat, sound: Team leverages OSC services to help confirm, interpret experimental findings May 29th, 2015

Two UCSB Professors Receive Early Career Research Awards: The Department of Energy’s award for young scientists acknowledges UC Santa Barbara’s standing as a top tier research institution May 29th, 2015

How spacetime is built by quantum entanglement: New insight into unification of general relativity and quantum mechanics May 28th, 2015

Squeezed quantum cats May 28th, 2015

Superconductivity

Linking superconductivity and structure May 28th, 2015

Visualizing How Radiation Bombardment Boosts Superconductivity: Atomic-level flyovers show how impact sites of high-energy ions pin potentially disruptive vortices to keep high-current superconductivity flowing May 23rd, 2015

Science and Technology of Advanced Materials (STAM): Reported successes and failures aid hot pursuit of superconductivity May 15th, 2015

Researchers discover 'swing-dancing' pairs of electrons: Findings set the stage for room-temperature superconductivity and the transformation of high-speed rail, quantum computers May 14th, 2015

Videos/Movies

Researchers develop new way to manufacture nanofibers May 21st, 2015

Artificial photosynthesis: New, stable photocathode with great potential May 12th, 2015

Molecular Nanotechnology

One step closer to a single-molecule device: Columbia Engineering researchers first to create a single-molecule diode -- the ultimate in miniaturization for electronic devices -- with potential for real-world applications May 25th, 2015

Nature inspires first artificial molecular pump: Simple design mimics pumping mechanism of life-sustaining proteins found in living cells May 19th, 2015

Feynman Prize Winners Announced! April 26th, 2015

Surface matters: Huge reduction of heat conduction observed in flat silicon channels April 23rd, 2015

Chip Technology

Stanford breakthrough heralds super-efficient light-based computers: Light can transmit more data while consuming far less power than electricity, and an engineering feat brings optical data transport closer to replacing wires May 29th, 2015

New chip makes testing for antibiotic-resistant bacteria faster, easier: Researchers at the University of Toronto design diagnostic chip to reduce testing time from days to one hour, allowing doctors to pick the right antibiotic the first time May 28th, 2015

Collaboration could lead to biodegradable computer chips May 28th, 2015

Physicists solve quantum tunneling mystery: ANU media release: An international team of scientists studying ultrafast physics have solved a mystery of quantum mechanics, and found that quantum tunneling is an instantaneous process May 27th, 2015

Quantum Computing

Donuts, math, and superdense teleportation of quantum information May 29th, 2015

Squeezed quantum cats May 28th, 2015

Advance in quantum error correction: Protocol corrects virtually all errors in quantum memory, but requires little measure of quantum states May 27th, 2015

Researchers discover 'swing-dancing' pairs of electrons: Findings set the stage for room-temperature superconductivity and the transformation of high-speed rail, quantum computers May 14th, 2015

Sensors

SouthWest NanoTechnologies Introduces AgeNT™ Transparent Conductor System at SID Display Week, Booth #543 May 28th, 2015

Technology for Tomorrow’s Market Opportunities and Challenges: LetiDays Grenoble Presents the Possibilities: June 24-25 Event Includes Focus on IoT-Augmented Mobility and Leti’s Latest Results on Silicon Technologies, Sensors, Health Applications and Smart Cities May 27th, 2015

This Slinky lookalike 'hyperlens' helps us see tiny objects: The photonics advancement could improve early cancer detection, nanoelectronics manufacturing and scientists' ability to observe single molecules May 23rd, 2015

Record high sensitive Graphene Hall sensors May 21st, 2015

Discoveries

Stanford breakthrough heralds super-efficient light-based computers: Light can transmit more data while consuming far less power than electricity, and an engineering feat brings optical data transport closer to replacing wires May 29th, 2015

Donuts, math, and superdense teleportation of quantum information May 29th, 2015

OSU researchers prove magnetism can control heat, sound: Team leverages OSC services to help confirm, interpret experimental findings May 29th, 2015

New technique speeds nanoMRI imaging: Multiplexing technique for nanoscale magnetic resonance imaging developed by researchers in Switzerland cuts normal scan time from two weeks to two days May 28th, 2015

Announcements

Stanford breakthrough heralds super-efficient light-based computers: Light can transmit more data while consuming far less power than electricity, and an engineering feat brings optical data transport closer to replacing wires May 29th, 2015

Donuts, math, and superdense teleportation of quantum information May 29th, 2015

OSU researchers prove magnetism can control heat, sound: Team leverages OSC services to help confirm, interpret experimental findings May 29th, 2015

Two UCSB Professors Receive Early Career Research Awards: The Department of Energy’s award for young scientists acknowledges UC Santa Barbara’s standing as a top tier research institution May 29th, 2015

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Stanford breakthrough heralds super-efficient light-based computers: Light can transmit more data while consuming far less power than electricity, and an engineering feat brings optical data transport closer to replacing wires May 29th, 2015

Donuts, math, and superdense teleportation of quantum information May 29th, 2015

OSU researchers prove magnetism can control heat, sound: Team leverages OSC services to help confirm, interpret experimental findings May 29th, 2015

Global Carbon Nanotubes (CNT) Market Expected To Reach USD 3.42 Billion By 2022 May 29th, 2015

Photonics/Optics/Lasers

Stanford breakthrough heralds super-efficient light-based computers: Light can transmit more data while consuming far less power than electricity, and an engineering feat brings optical data transport closer to replacing wires May 29th, 2015

DNA Double Helix Does Double Duty in Assembling Arrays of Nanoparticles: Synthetic pieces of biological molecule form framework and glue for making nanoparticle clusters and arrays May 25th, 2015

This Slinky lookalike 'hyperlens' helps us see tiny objects: The photonics advancement could improve early cancer detection, nanoelectronics manufacturing and scientists' ability to observe single molecules May 23rd, 2015

Samtec, Global Provider of Interconnect Systems, Joins IRT Nanoelec Silicon Photonics Program May 21st, 2015

Quantum nanoscience

Physicists solve quantum tunneling mystery: ANU media release: An international team of scientists studying ultrafast physics have solved a mystery of quantum mechanics, and found that quantum tunneling is an instantaneous process May 27th, 2015

Quantum physics on tap - Nano-sized faucet offers experimental support for longstanding quantum theory May 16th, 2015

Researchers discover 'swing-dancing' pairs of electrons: Findings set the stage for room-temperature superconductivity and the transformation of high-speed rail, quantum computers May 14th, 2015

Researchers build new fermion microscope: Instrument freezes and images 1,000 individual fermionic atoms at once May 13th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project