ISSN:0031-9228    

DOI:10.1063/1.2810390

出版商:AIP    

年代:1990

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2810391

出版商:AIP    

年代:1990

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2810393

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Glasses were raised at a conference at the University of South Carolina in December to toast the 30‐year‐old prediction that gave reality to the magnetic vector potential. According to that prediction, made by Yakir Aharonov (University of South Carolina and the University of Tel Aviv) and David Bohm (Birkbeck College of London University), an electron will experience a phase shift as it encircles an infinitely long solenoid, even though there is no magnetic field—only a vector potential—in the region where it travels. Almost all those who originally doubted this conclusion have long since been persuaded by several elegant experimental confirmations.

ISSN:0031-9228    

DOI:10.1063/1.2810394

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

In the fractional quantum Hall effect, the Hall conductance is quantized. In the most common manifestation of the effect, which was first observed in the two‐dimensional electron gas sandwiched between the semiconducting layers of a GaAs‐AlGaAs heterostructure, the magnetic field dependence of the Hall resistance shows an ascending‐staircase‐type behavior with increasing field strength. The steps in the staircase correspond to Hall conductance values of the form(p/q)e2/h,and they occur around the magnetic field values for which the number of electrons per magnetic field quantum isp/q,withpandqintegers andqusually odd.

ISSN:0031-9228    

DOI:10.1063/1.2810395

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

On 12 October the Stanford Linear Accelerator Center announced its finding that Nature has only three families of elementary particles.’ (SeePHYSICS TODAY, October, page 17) Five days later, as if in anger at having its secret revealed, Nature shook the offending instrument—the recently completed Stanford Linear Collider—by the throat. All things considered, the SLC has suffered relatively little damage from the historic earthquake that struck the San Francisco Bay area at 5:04 pm on 17 October. Still, the small misalignments caused by the quake have interrupted the physics schedule of the collider for more than a month. As of this writing, the fond expectation at SLAC is for “a few moreZ°'s by Christmas.”

ISSN:0031-9228    

DOI:10.1063/1.2810396

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Research in macroscopic classical physics, such as fluid dynamics or aspects of condensed matter physics, continues to confront baffling challenges that are by no means less demanding than those at the post‐Newtonian frontiers of physics that have been explored since the beginning of this century. This is so even though the basic equations of macroscopic classical physics are known—indeed, have been known for centuries in many cases. Chaos and nonlinear dynamics are examples of the topics that pose new challenges to our understanding of macroscopic classical systems. Turbulence, a phenomenon related to but distinct from chaos, and having strong roots in engineering, has been increasingly in the focus of physics research in recent years.

ISSN:0031-9228    

DOI:10.1063/1.881235

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Mikhail Gorbachev's program ofglasnostandperestroika—now in its fifth year—has wrought striking changes inside the Soviet Union, and even more spectacular metamorphoses outside its borders. Among the positive repercussions of the Gorbachev program on the international scene, we have seen major improvements in international scientific cooperation. In particle physics the improvement during the years of the Gorbachev de´tente appears less dramatic than it does in space science, for example. But that's largely because the opportunity to solidify East‐West cooperation in particle physics had been seized much earlier—during the Khrushchev de´tente of 1956–60, a time when this field, with its large and expensive accelerators, stood alone as the epitome of “big science.”

ISSN:0031-9228    

DOI:10.1063/1.881236

出版商:AIP    

年代:1990

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2810397

出版商:AIP    

年代:1990

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2810398

出版商:AIP    

年代:1990

数据来源: AIP