Pixel Tracker

Monday, February 18 , 2019, 1:18 pm | A Few Clouds 57º

 
 
 
 

UCSB Physicists Make Strides in Understanding Quantum Entanglement

While some theoretical physicists make predictions about astrophysics and the behavior of stars and galaxies, others work in the realm of the very small, which includes quantum physics. Such is the case at UC Santa Barbara, where theoretical physicists at the Kavli Institute for Theoretical Physics cover the range of questions in physics.

Leon Balents
Leon Balents

Recently, theoretical physicists at KITP have made important strides in studying a concept in quantum physics called quantum entanglement, in which electron spins are entangled with each other. Using computers to calculate the extreme version of quantum entanglement –– how the spin of every electron in certain electronic materials could be entangled with another electron’s spin –– the research team found a way to predict this characteristic. Future applications of the research are expected to benefit fields such as information technology.

“Quantum entanglement is a strange and non-intuitive aspect of the quantum theory of matter, which has puzzled and intrigued physicists since the earliest days of the quantum theory,” said Leon Balents, senior author of a recent paper on this topic published in the journal Nature Physics. Balents is a professor of physics and a permanent member of KITP.

Quantum entanglement represents the extent to which measurement of one part of a system affects the state of another; for example, measurement of one electron influences the state of another that may be far away, explained Balents. In recent years, scientists have realized that entanglement of electrons is present in varying degrees in solid materials. Taking this notion to the extreme is the “quantum spin liquid,” a state of matter in which every electron spin is entangled with another.

Balents said quantum spin liquids are being sought in experiments on natural and artificial minerals. A key question posed by physicists is how to calculate theoretically which materials are quantum spin liquids.

“In our paper, we provide an answer to this question, showing that a precise quantitative measure of ‘long-range’ entanglement can be calculated for realistic models of electronic materials,” Balents said. “Our results provide a smoking gun signature of this special type of entanglement that determines whether or not a given material is a quantum spin liquid.”

The results prove that an emblematic example of this type of problem –– material with electron spins residing on the “kagome lattice” –– is indeed a quantum spin liquid, according to Balents. The kagome lattice is a pattern of electron spins named after a type of Japanese fishing basket that this arrangement of spins resembles.

“We expect the technique we developed to have broad applications in the search for these unique quantum states, which in the future may have remarkable applications in information technologies,” Balents said.

Hong-Chen Jiang, postdoctoral fellow with KITP, and Zhenghan Wang, a researcher with Microsoft Station Q at UCSB, are co-authors of the paper.

Talk to Us!

Please take Noozhawk's audience survey to help us understand what you expect — and want — from us. It'll take you just a few minutes. Thank you!

Get Started >

Support Noozhawk Today

You are an important ally in our mission to deliver clear, objective, high-quality professional news reporting for Santa Barbara, Goleta and the rest of Santa Barbara County. Join the Hawks Club today to help keep Noozhawk soaring.

We offer four membership levels: $5 a month, $10 a month, $25 a month or $1 a week. Payments can be made using a credit card, Apple Pay or Google Pay, or click here for information on recurring credit-card payments and a mailing address for checks.

Thank you for your vital support.

Become a Noozhawk Supporter

First name
Last name
Email
Select your monthly membership
Or choose an annual membership
×

Payment Information

Membership Subscription

You are enrolling in . Thank you for joining the Hawks Club.

Payment Method

Pay by Credit Card:

Mastercard, Visa, American Express, Discover
One click only, please!

Pay with Apple Pay or Google Pay:

Noozhawk partners with Stripe to provide secure invoicing and payments processing.
You may cancel your membership at any time by sending an email to .(JavaScript must be enabled to view this email address).

  • Ask
  • Vote
  • Investigate
  • Answer

Noozhawk Asks: What’s Your Question?

Welcome to Noozhawk Asks, a new feature in which you ask the questions, you help decide what Noozhawk investigates, and you work with us to find the answers.

Here’s how it works: You share your questions with us in the nearby box. In some cases, we may work with you to find the answers. In others, we may ask you to vote on your top choices to help us narrow the scope. And we’ll be regularly asking you for your feedback on a specific issue or topic.

We also expect to work together with the reader who asked the winning questions to find the answer together. Noozhawk’s objective is to come at questions from a place of curiosity and openness, and we believe a transparent collaboration is the key to achieve it.

The results of our investigation will be published here in this Noozhawk Asks section. Once or twice a month, we plan to do a review of what was asked and answered.

Thanks for asking!

Click Here to Get Started >

Reader Comments

Noozhawk is no longer accepting reader comments on our articles. Click here for the announcement. Readers are instead invited to submit letters to the editor by emailing them to [email protected]. Please provide your full name and community, as well as contact information for verification purposes only.