摘要:

The National Academy of Sciences will be expanding its public outreach operations by launching a new science policy museum. The 557‐square‐meter Marian Koshland Science Museum, scheduled to open at the end of April in Washington, DC, will attempt to explain the science behind current and sometimes controversial public policy issues (see http://www.koshland‐science‐museum.org).

ISSN:0031-9228    

DOI:10.1063/1.1712493

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

On 2 February, Amy Flatten became head of international affairs at the American Physical Society. She took the torch from Irving Lerch, who stepped down last December, 11 years after founding the program.

ISSN:0031-9228    

DOI:10.1063/1.1712495

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

The job market for recent PhDs in Earth and space sciences remained strong for the class of 2002: 88&percent; are working in their field and describe their jobs as challenging and relevant, according to a recent report by the American Geological Institute, the American Geophysical Union, and the American Institute of Physics.

ISSN:0031-9228    

DOI:10.1063/1.1712496

出版商:AIP    

年代:1904

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1712497

出版商:AIP    

年代:1904

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1712499

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

The success story of quantum optics during the past 10 years is largely based on progress in gaining control of systems at the single‐quantum level while suppressing unwanted interactions with the environment, which cause decoherence. Those achievements, illustrated by storage and laser cooling of single trapped ions and atoms and by the manipulation of single photons in cavity quantum electrodynamics, have opened a new field: the engineering of interesting and useful quantum states. In the meantime, the frontier has moved toward building larger composite systems of a few atoms and photons while still maintaining complete quantum control of the individual particles. The new physics to be studied in these systems is based on entangled states and ranges from a fundamental point of testing quantum mechanics for larger and larger systems to possible new applications such as quantum information processing and precision measurements.

ISSN:0031-9228    

DOI:10.1063/1.1712500

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Since the mid‐1980s, astronomers and astrophysicists have been accumulating evidence that the expansion of the universe is accelerating (see the article by Saul Perlmutter in PHYSICSTODAY, April 2003, page 53). The simplest way to incorporate that acceleration into the description of cosmology, within the framework of general relativity, is to add a cosmological constant (CC) term to the Einstein equations. Before Edwin Hubble discovered the expansion of the universe, Albert Einstein had originally introduced such a term to obtain a static solution of his cosmological equations. After the cosmic expansion was discovered, Einstein considered his introduction of the CC to be the greatest mistake of his career.

ISSN:0031-9228    

DOI:10.1063/1.1712501

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Modern solid‐state physics explains the physical properties of numerous materials, such as simple metals and some semiconductors and insulators. But materials with opendandfelectron shells, where electrons occupy narrow orbitals, have properties that are harder to explain. In transition metals, such as vanadium, iron, and their oxides, for example, electrons experience strong Coulombic repulsion because of their spatial confinement in those orbitals. Such strongly interacting or “correlated” electrons cannot be described as embedded in a static mean field generated by the other electrons. The influence of an electron on the others is simply too pronounced for each to be treated independently.

ISSN:0031-9228    

DOI:10.1063/1.1712502

出版商:AIP    

年代:1904

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1712503

出版商:AIP    

年代:1904

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1712504

出版商:AIP    

年代:1904

数据来源: AIP