• UCSBgauchos twitter avatar
    Softball: Gauchos Split Final Road Games at Hawai'i https://t.co/CpEDdmmhVc
    8 hours 54 min ago
  • UCSBgauchos twitter avatar
    Gauchos are live on @ESPN3 ! WATCH >>> https://t.co/io6ZzYs9Hg https://t.co/BEO8wTxv62
    14 hours 46 sec ago
  • ucsantabarbara twitter avatar
    Congrats to Leah Foltz for winning the #UCSB Grad Slam! Now she moves onto the UC-wide competition in SF on May 4th! https://t.co/kVqCtOTWb7
    20 hours 54 min ago
  • UCSBgauchos twitter avatar
    Former @UCSB_Baseball LHP Dom Mazza speaks with his hometown paper after throwing a perfecto this week! https://t.co/GPc3B3qL9g
    21 hours 14 min ago
  • ArtsandLectures twitter avatar
    Watch pianist #MurrayPerahia's breathtaking and imaginative performance, tonight at 7PM at UCSB Campbell Hall!… https://t.co/M83EeA6Y53
    23 hours 59 min ago
  • UCSBgauchos twitter avatar
    Softball: Hawai'i Tops UCSB 5-1 in Gauchos' Final Road Series Opener https://t.co/ejf0MWM1g0
    1 day 7 hours ago
  • UCSBgauchos twitter avatar
    Gauchos Sweep Past UCI 4-0 https://t.co/WFwbxDV8eA
    1 day 9 hours ago
  • ucsantabarbara twitter avatar
    We're happy to see you back, alumni! Don't miss the great events we have this weekend. #AllGauchoReunion… https://t.co/Sbz4iirr7i
    1 day 13 hours ago
  • UCSBgauchos twitter avatar
    Women's Tennis: Cal Poly 0, UC Santa Barb. 4 (Final) No.2 UCSB blanks No.7 Cal Poly in Big West Quarterfinal 4-0 https://t.co/m4kdACQFo5
    1 day 13 hours ago
  • UCSBgauchos twitter avatar
    .@UCSB_Baseball vs. UC Riverside on @ESPN3 is live now! Watch here >>> https://t.co/QJMvNLa0mQ
    1 day 13 hours ago
  • UCSBgauchos twitter avatar
    WWP: Defending Big West Champs Defeated by No. 12 LBSU in Another Overtime Match https://t.co/XIO3RJdo9p
    1 day 14 hours ago
  • UCSBgauchos twitter avatar
    Top-Seeded UCSB Set to Host Big West Golf Championship at Sandpiper GC https://t.co/SyXPKB2Ur5
    1 day 15 hours ago
  • UCSBLibrary twitter avatar
    RT @ForestSways: CEMA poster preservation for primary source research. #Chicanohertiage @Marikhasmanyan @UCSBLibrary #sca17 https://t.co/M…
    1 day 17 hours ago
  • UCSBLibrary twitter avatar
    @AmldavisAnn We're glad you're interested in using, please contact (805) 893-3062 or @library.ucsb.edu">special@library.ucsb.edu for m… https://t.co/fwAVOMoWyB
    1 day 17 hours ago
  • UCSB_GradPost twitter avatar
    CPT F-1 Visa workshop for international students on May 11 https://t.co/l6xZEndRVl #UCSB #ucsbgradpost
    1 day 18 hours ago

One Kind of Supersymmetry Shown to Emerge Naturally

A UCSB physicist outlines how this unique phenomenon occurs in a condensed matter system
Wednesday, April 9, 2014 - 10:00
Santa Barbara, CA

Supersymmetry fig1 ENH.jpg

Supersymmetry figure 1

Supersymmetry in a three-dimensional topological superconductor: Ising magnetic fluctuations (denoted by red arrows) at the boundary couple to the fermions (blue cone).

Tarun Grover.jpg

Tarun Grover

Tarun Grover

Photo Credit: 

Spencer Bruttig

UC Santa Barbara physicist Tarun Grover has provided definitive mathematical evidence for supersymmetry in a condensed matter system. Sought after in the realm of subatomic particles by physicists for several decades, supersymmetry describes a unique relationship between particles.

“As yet, no one has found supersymmetry in our universe, including at the Large Hadron Collider (LHC),” said the associate specialist at UCSB’s Kavli Institute for Theoretical Physics (KITP). He is referring to the underground laboratory in Switzerland where the famous Higgs boson was identified in 2012. “This is a fresh insight as to how supersymmetry arises in nature.” The findings of Grover’s research, conducted with colleagues Donna Sheng and Ashvin Vishwanath, appear in the current online edition of the journal Science.

The fundamental constituents of matter — electrons, quarks and their relatives — are fermions. The particles associated with fundamental forces are called bosons. Several decades ago, physicists hypothesized that every type of particle in the Standard Model of particle physics, a theory that captures the dynamics of known subatomic particles, has one or more superpartners — other types of particles that share many of the same properties but differ in a crucial way.

If a particle is a fermion, its superpartner is a boson, and if a particle is a boson, its superpartner is a fermion. This is supersymmetry, a postulated unique theoretical symmetry of space.

While the Standard Model governing the ordinary world is not supersymmetric, it is often theorized that the more “fundamental” theory relevant to very hot systems, such as those probed in high-energy particle accelerators like the LHC (or higher energy ones yet to be built), might exhibit supersymmetry. This has yet to be proved or disproved by accelerator experiments.

However, through their calculations, Grover and his co-authors show that supersymmetry emerges naturally in a topological superconductor. An example is helium-3, a light, nonradioactive isotope of helium with two protons and one neutron (common helium has two neutrons). When helium-3 is cooled to almost absolute zero (0 Kelvin), it becomes a liquid superconductor. As understood only recently, the boundary of its container features fermions.

“The reason these fermions exist is related to time-reversal symmetry, which is unrelated to supersymmetry,” said Grover. A video of an object tossed vertically up in the air is a good example of time-reversal symmetry. When the video is played back, it shows the object following the same parabolic trajectory through the air as it did when the video was played normally. “We wanted to see what would happen to these fermions when time-reversal symmetry was broken,” Grover explained.

The scientists theorized that the application of a specified amount of magnetic field to the surface of the container would break the time-reversal symmetry. This, in turn, would cause the fermions to disappear due to their interaction with bosons that already exist in the liquid helium-3. Grover and his coauthors found that right at the point when fermions are about to disappear, the fermions and the bosons behave as superpartners of each other, thus providing a condensed matter analog of supersymmetry.

According to physicists, if supersymmetry can be proved in high-energy experiments, it opens the door to answers that physicists have been seeking for years and may pave the way to analyze and even integrate different fundamental physics theories such as quantum field theory, string theory and Einstein’s relativity.

“Grover’s team shows that supersymmetry may be studied in low-energy experiments,” said physics professor Leon Balents, Grover’s colleague at KITP. “This would be amazing in its own right and could serve as an inexpensive tabletop model for what to look for at particle accelerators.”

“Our paper provides insight into how and in what systems supersymmetry may emerge in a very natural way,” Grover said. “Maybe it doesn’t exist in our actual universe, but there exist these condensed matter systems, such as topological superconductors, where supersymmetry can exist. This opens the window for experimentalists to go and test supersymmetry and its exciting consequences in real life.”

Contact Info: 

Julie Cohen
julie.cohen@ucsb.edu
(805) 893-7220

Topics: