Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Quantum shift shows itself in coupled light and matter: Rice University scientists corral, quantify subtle movement in condensed matter system

Researchers at Rice University, including graduate student Xinwei Li, have observed and measured a Bloch-Siegert shift in strongly coupled light and matter in a vacuum. The project could aid in the development of quantum computers. (Credit: Jeff Fitlow/Rice University)
Researchers at Rice University, including graduate student Xinwei Li, have observed and measured a Bloch-Siegert shift in strongly coupled light and matter in a vacuum. The project could aid in the development of quantum computers. (Credit: Jeff Fitlow/Rice University)

Abstract:
A team led by Rice University scientists used a unique combination of techniques to observe, for the first time, a condensed matter phenomenon about which others have only speculated. The research could aid in the development of quantum computers.

.

An electron (blue sphere) travels in a circular orbit in a DC magnetic field (B_dc). When an incoming light wave (E_ac) interacts with it, there is a component in the light wave whose electric field rotates in the same direction with the electron motion (red arrow on the left-hand side) and thus resonantly interacts with it – that is, the electron rapidly gains energy. The other component of the electric field rotates in the opposite direction with the electron (red arrow on the right-hand side), whose effect is typically negligible. However, when the electron and light wave mix to an extreme degree, the interaction effect can manifest as a Bloch-Siegert shift. (Credit: Xinwei Li/Kono Lab at Rice University)

Quantum shift shows itself in coupled light and matter: Rice University scientists corral, quantify subtle movement in condensed matter system

Houston, TX | Posted on April 16th, 2018

The researchers, led by Rice physicist Junichiro Kono and graduate student Xinwei Li, observed and measured what's known as a Bloch-Siegert shift in strongly coupled light and matter.

Results of the complicated combination of modeling and experimentation are the subject of a paper in Nature Photonics. The technique could lead to a greater understanding of theoretical predictions in quantum phase transitions because the experimental parameters used in the Rice experiments are highly adjustable, according to Kono. Ultimately, he said, it may help in the development of robust quantum bits for advanced computing.

The Bloch-Siegert shift, a theory born in the 1940s, is a quantum interaction in which counter-rotating fields are able to interact. But such interactions have been difficult to detect.

The theory suggested to Kono and Li that it might be possible to detect such a shift when a light field rotating in one direction strongly couples with a matter-bound electron field rotating in the opposite direction. These interactions have proven difficult to create without the unique tools assembled by the Rice-led team.

"Light and matter should not resonate with each other when they are rotating in opposite directions," Kono said. "However, in our case, we proved they can still strongly couple, or interact, even though they are not resonating with each other."

Kono and his colleagues created the resonance frequency shift in a two-level electron system induced by coupling with an electromagnetic field inside a cavity even when the electrons and field are rotating in opposite directions – a truly surprising effect that occurs only in a regime where light and matter are mixed together to an extreme degree.

In this case, the levels are those of two-dimensional electrons in solid gallium arsenide in a strong perpendicular magnetic field. They hybridize with the "vacuum" electromagnetic field in the cavity to form quasiparticles known as polaritons. This vacuum-matter hybridization had been expected to lead to a finite frequency shift, a vacuum Bloch-Siegert shift, in optical spectra for circularly polarized light counter-rotating with the electrons. The Rice team can now measure it.

"In condensed matter physics, we often look for new ground states (lowest-energy states). For that purpose, light-matter coupling is usually considered an enemy because light drives matter to an excited (higher-energy) state," Kono said. "Here we have a unique system that is predicted to go into a new ground state because of strong light-matter coupling. Our technique will help us know when the strength of light-matter coupling exceeds a certain threshold."

The research builds upon a strong vacuum field-matter coupling in a high-quality-factor cavity the lab first created and reported in 2016. The results at the time only hinted at the presence of a Bloch-Siegert shift. "Experimentally, we just demonstrated the new regime," Li said. "But here, we have a very deep understanding of the physics involved."

Kono and Li credited physicist Motoaki Bamba of Osaka University for providing a theoretical basis for the discovery and Katsumasa Yoshioka of Yokohama National University and a former visiting scholar at Rice for providing a device to produce circularly polarized light in the terahertz range of the electromagnetic spectrum.

The lab used the light to probe the shift in an ultra-high quality, two-dimensional electron gas supplied by Purdue University physicist Michael Manfra and set in a gallium arsenide quantum well (to contain the particles) under the influence of a strong magnetic field and low temperature. A terahertz spectroscope measured activity in the system.

"Linearly polarized light means an alternating current electric field that is always oscillating in one direction," Kono said. "In circularly polarized light, the electric field is rotating." That allowed the researchers to distinguish between left- and right-rotating electrons in their vacuum-bound condensed matter in a magnetic field, and from that, measure the shift.

"In this work, both theoretically and experimentally, we demonstrated that even though the electron is rotating this way and the light is rotating (the other) way, they still strongly interact with each other, which leads to a finite frequency shift known as the Bloch-Siegert shift," Kono said.

Observing the shift is a direct indication that ultra-strong light-matter coupling invalidated the rotating wave approximation, he said. "That approximation is behind almost all light-matter interaction phenomenon, including lasers, nuclear magnetic resonance and quantum computing," Kono said. "In any resonant light-matter interaction, people are satisfied with this approximation, because the coupling is usually weak. But if the coupling between light and matter is strong, it doesn't work. That's clear evidence that we are in the ultra-strong coupling regime."

Co-authors of the paper are Rice postdoctoral researcher Weilu Gao and graduate student Minhan Lou of Rice, Rice alumnus Qi Zhang of Argonne National Laboratory and graduate student Saeed Fallahi and visiting scholar Geoff Gardner of Purdue. Kono is a professor of electrical and computer engineering, of physics and astronomy, and of materials science and nanoengineering. Manfra is the Bill and Dee O’Brian Chair Professor of Physics and Astronomy at Purdue. Bamba is an associate professor at Osaka. Yoshioka is a teaching assistant at Yokohama.

The National Science Foundation, the Army Research Office, the Department of Energy Office of Basic Energy Sciences, the PRESTO program of the Japan Science and Technology Agency and the ImPACT program of the Government of Japan's Council for Science, Technology and Innovation supported the research.

####

About Rice University
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,970 undergraduates and 2,934 graduate students, Rice’s undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for quality of life and for lots of race/class interaction and No. 2 for happiest students by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger’s Personal Finance. To read “What they’re saying about Rice,” go to http://tinyurl.com/RiceUniversityoverview .

Follow Rice News and Media Relations via Twitter @RiceUNews

For more information, please click here

Contacts:
David Ruth
713-348-6327


Mike Williams
713-348-6728

Copyright © Rice University

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

Read the open-access paper at:

Kono Laboratory:

Motoaki Bamba:

Manfra Group:

Katsumasa Yoshioka:

Rice Department of Electrical and Computer Engineering:

Rice Department of Physics and Astronomy:

Rice Department of Materials Science and NanoEngineering:

Related News Press

Quantum Physics

Researchers’ approach may protect quantum computers from attacks March 8th, 2024

News and information

Researchers develop artificial building blocks of life March 8th, 2024

How surface roughness influences the adhesion of soft materials: Research team discovers universal mechanism that leads to adhesion hysteresis in soft materials March 8th, 2024

Two-dimensional bimetallic selenium-containing metal-organic frameworks and their calcinated derivatives as electrocatalysts for overall water splitting March 8th, 2024

Curcumin nanoemulsion is tested for treatment of intestinal inflammation: A formulation developed by Brazilian researchers proved effective in tests involving mice March 8th, 2024

Videos/Movies

New X-ray imaging technique to study the transient phases of quantum materials December 29th, 2022

Solvent study solves solar cell durability puzzle: Rice-led project could make perovskite cells ready for prime time September 23rd, 2022

Scientists prepare for the world’s smallest race: Nanocar Race II March 18th, 2022

Visualizing the invisible: New fluorescent DNA label reveals nanoscopic cancer features March 4th, 2022

Govt.-Legislation/Regulation/Funding/Policy

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Researchers’ approach may protect quantum computers from attacks March 8th, 2024

The Access to Advanced Health Institute receives up to $12.7 million to develop novel nanoalum adjuvant formulation for better protection against tuberculosis and pandemic influenza March 8th, 2024

Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024

Possible Futures

Two-dimensional bimetallic selenium-containing metal-organic frameworks and their calcinated derivatives as electrocatalysts for overall water splitting March 8th, 2024

Curcumin nanoemulsion is tested for treatment of intestinal inflammation: A formulation developed by Brazilian researchers proved effective in tests involving mice March 8th, 2024

The Access to Advanced Health Institute receives up to $12.7 million to develop novel nanoalum adjuvant formulation for better protection against tuberculosis and pandemic influenza March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

Quantum Computing

Researchers’ approach may protect quantum computers from attacks March 8th, 2024

Physicists ‘entangle’ individual molecules for the first time, hastening possibilities for quantum information processing: In work that could lead to more robust quantum computing, Princeton researchers have succeeded in forcing molecules into quantum entanglement December 8th, 2023

World’s first logical quantum processor: Key step toward reliable quantum computing December 8th, 2023

Optical-fiber based single-photon light source at room temperature for next-generation quantum processing: Ytterbium-doped optical fibers are expected to pave the way for cost-effective quantum technologies November 3rd, 2023

Discoveries

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Researchers’ approach may protect quantum computers from attacks March 8th, 2024

High-tech 'paint' could spare patients repeated surgeries March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

Announcements

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Curcumin nanoemulsion is tested for treatment of intestinal inflammation: A formulation developed by Brazilian researchers proved effective in tests involving mice March 8th, 2024

The Access to Advanced Health Institute receives up to $12.7 million to develop novel nanoalum adjuvant formulation for better protection against tuberculosis and pandemic influenza March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

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

Researchers develop artificial building blocks of life March 8th, 2024

How surface roughness influences the adhesion of soft materials: Research team discovers universal mechanism that leads to adhesion hysteresis in soft materials March 8th, 2024

Curcumin nanoemulsion is tested for treatment of intestinal inflammation: A formulation developed by Brazilian researchers proved effective in tests involving mice March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

Military

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

The Access to Advanced Health Institute receives up to $12.7 million to develop novel nanoalum adjuvant formulation for better protection against tuberculosis and pandemic influenza March 8th, 2024

New chip opens door to AI computing at light speed February 16th, 2024

NRL discovers two-dimensional waveguides February 16th, 2024

Quantum nanoscience

Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024

Bridging light and electrons January 12th, 2024

'Sudden death' of quantum fluctuations defies current theories of superconductivity: Study challenges the conventional wisdom of superconducting quantum transitions January 12th, 2024

Physicists ‘entangle’ individual molecules for the first time, hastening possibilities for quantum information processing: In work that could lead to more robust quantum computing, Princeton researchers have succeeded in forcing molecules into quantum entanglement December 8th, 2023

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




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project