ISSN:0031-9228    

DOI:10.1063/1.2408611

出版商:AIP    

年代:1904

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1839351

出版商:AIP    

年代:1904

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1839352

出版商:AIP    

年代:1904

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1839367

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Suppose you could freeze the water in a washing machine while it was operating. Once the water had solidified, the machine's agitators would cause the entire icy mass to oscillate—until the motor burned out. In January of this year, Eun‐Seong Kim and Moses Chan, both at Pennsylvania State University, reported an experiment that has some of the flavor of the washing‐machine fantasy, but which yielded a surprising result (see PHYSICSTODAY, April 2004, page 21). They introduced liquid helium‐4 into a torsional oscillator, solidified the liquid at high pressure, and lowered the temperature. When the temperature fell below about 175 mK, the period of the resonant oscillation also began to fall. About 1&percent; of the4Hein the oscillator appeared not to move with the bulk oscillation; it behaved as a superfluid would.

ISSN:0031-9228    

DOI:10.1063/1.1839368

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Reaching the limit where a single atom couples strongly enough with a single photon to exhibit coherent behavior has been a major focus in quantum optics for much of the past two decades. That strong coupling limit is hard to achieve because photons and atoms interact so weakly in general. But by placing an atom inside a small optical cavity bounded by mirrors that are reflective enough to trap a photon for hundreds or thousands of roundtrips before it escapes, researchers can strengthen the interaction.

ISSN:0031-9228    

DOI:10.1063/1.1839369

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

In the past 10 years, some 120 planets have been discovered outside the solar system. With the exception of three lightweight oddballs orbiting a millisecond pulsar—the dead remnant of a supernova—all of these exoplanets have been at least two orders of magnitude heavier than Earth. Though observational biases clearly favor the discovery of such giants, astronomers couldn't help wondering whether, for some unknown reason, lighter exoplanets might in fact be much rarer than gas giants like our own Jupiter and Saturn.

ISSN:0031-9228    

DOI:10.1063/1.1839370

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

“I was immediately obsessed,” says Timothy Koeth, who, as a sophomore in physics in 1995 at Rutgers University, got the bug to build a cyclotron. “I was sitting in Tom Devlin's modern physics lecture,” recalls Koeth. “He described the principle of the cyclotron. He said it required a lot of RF power. I was—and am—a ham radio operator, so RF was no problem. It needed a big magnet; I knew I could find one of those. How tough could a vacuum system and chamber be?” Some six years later, Koeth's 12‐inch machine became part of an undergraduate lab course.

ISSN:0031-9228    

DOI:10.1063/1.1839371

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

In response to a safety violation and a supposed security breach this summer, Los Alamos National Laboratory has fired four people and punished eight others. In a 15 September memo to lab staff, LANL Director G. Peter Nanos wrote, “It is now time to begin conscientiously moving forward in a safe, secure and compliant manner. The period of the last several months marks a new beginning for this institution.” But many lab scientists, bitter about Nanos's handling of the safety and security lapses, are skeptical about how new the beginning really is. “Nanos sowed the seeds of discontent, and there is now a lush garden,” says Rhonald Keinigs, a longtime LANL weapons scientist.

ISSN:0031-9228    

DOI:10.1063/1.1839372

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Geneticist Gerald Rubin sat in the nondescript conference room of a leftover building that once belonged to a now‐defunct software company and talked like a scientist possessed by a vision.

ISSN:0031-9228    

DOI:10.1063/1.1839373

出版商:AIP    

年代:1904

数据来源: AIP