SLAC Today is available online at:
http://today.slac.stanford.edu

In this issue:
September Public Lecture to Focus on Exotic New Materials for Future Devices
FY2010 Travel Reimbursement Deadline: September 8
Phone Outage Scheduled for Saturday
In the News: Void That is Truly Empty Solves Dark Energy Puzzle

SLAC Today

Thursday - September 2, 2010

September Public Lecture to Focus on Exotic New Materials for Future Devices

Poster by SLAC InfoMedia Solutions

On September 28 at 7:30 p.m., Yulin Chen of the Stanford Institute for Materials and Energy Science will present the public lecture Leading the Charge: Exotic New Materials for Future Devices.

To improve computer technology and create chips that are significantly smaller, faster, and more efficient, researchers need to create new types of semiconductors. A new class of materials—the "topological insulators"—achieve robust performance by tying the paths of electrons in knots. These materials arose from a bold theoretical proposal that was recently verified by X-ray experiments at SLAC. In this lecture, Chen will describe the special properties of these materials and the promise for their applications.

The lecture will take place in SLAC's Panofsky Auditorium. For more information, visit the SLAC Public Lecture Web site.

FY2010 Travel Reimbursement Deadline: September 8

SLAC's 2010 fiscal year is coming to a close. In preparation for closing the accounting books, please submit all outstanding Travel Expense Reports by the deadlines below so they can be entered as part of FY2010 expenses either by payment or by accrual.

Wednesday, September 8 at 5:00 p.m. – The Travel Reimbursement Office will reimburse travelers for all expense reports received by September 8th before the end of September.

Monday, September 20 at 5:00 p.m. – The Travel Reimbursement Office will accrue all expense reports received by September 20th, but cannot assure payment before October.

The Travel Reimbursement Office asks you to help by submitting your expense reports as soon as possible.

If you have any questions, please contact the SLAC Travel Reimbursement Office.

Phone Outage Scheduled for Saturday

SLAC will experience a partial phone outage this Saturday to allow for maintenance on one of the shelves of the laboratory's telecommunications equipment.

The outage will affect approximately 480 phone lines. At some point during the maintenance, these extensions will not have dial-tone. However, you will be able to dial in to the Call Pilot voicemail system and retrieve messages either from another extension or from a non-SLAC phone line.

The maintenance is scheduled for this Saturday, September 4, at 9 a.m. It should be completed by 11 a.m.

A list of all the affected extensions is available online (Excel file).

In the News: Void That is Truly Empty Solves Dark Energy Puzzle

Empty space may really be empty. Though quantum theory suggests that a vacuum should be fizzing with particle activity, it turns out that this paradoxical picture of nothingness may not be needed. A calmer view of the vacuum would also help resolve a nagging inconsistency with dark energy, the elusive force thought to be speeding up the expansion of the universe.

Quantum field theory tells us that short-lived pairs of particles and their antiparticles are constantly being created and destroyed in apparently empty space. A branch of the theory, called quantum chromodynamics (QCD)—which explains how gluons and quarks, the particles that make up protons and neutrons, behave—predicts that a vacuum should be awash with an interacting sea or "condensate" of quarks and gluons. This picture helps to explain how particles made of quarks get most of their mass.

This condensate carries energy, so it might be thought to be a candidate for the mysterious source of dark energy, which can be described by a parameter called the cosmological constant. The trouble is that when physicists use QCD to estimate the condensate's energy density, their calculations suggest it would pack a punch that is 1045 times the cosmological constant that we measure from observations of the universe's expansion.

Now Stanley Brodsky of the SLAC National Accelerator Laboratory in Menlo Park, California, and colleagues [Robert Shrock, Peter Tandy and Craig Roberts] have found a way to get rid of the discrepancy.  Read more in New Scientist...

Events

Access (see all)

Announcements
(see all | submit)

 Lab Announcements

Community Bulletin Board

Training (see all | register)

Lab Training

Upcoming Workshops & Classes

News (submit)

dividing line
(Office of Science/U.S. DOE Logo)

View online at http://today.slac.stanford.edu/.