ISSN:0031-9228    

DOI:10.1063/1.2807931

出版商:AIP    

年代:1995

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2807932

出版商:AIP    

年代:1995

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2807933

出版商:AIP    

年代:1995

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2807934

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Perturbation theory has long been one of the most successful tools in quantum field theory. The technique produces a series of terms, and ideally most of the “physics” is captured by the more readily computed early teims in the expansion, with later terms supplying progressively more negligible corrections. In contrast to such approximations, exact computations in four‐dimensional quantum field theory have been few and far between. As Stephen Shenker (Rutgers University) puts it, “The conventional wisdom was that exact results in four‐dimensional quantum field theory were essentially unobtainable.” This lack of analytic results has been particularly problematic for the theory of quark confinement, which involves the strong force in a thoroughly nonperturbative regime.

ISSN:0031-9228    

DOI:10.1063/1.2807935

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

When high‐temperature superconductivity reached temperatures above that of liquid nitrogen eight years ago, thousands of researchers jumped in, lots of funding followed, and the most enthusiastic people talked of magnetically levitated trains, computers and motors all soon to be operating above 77 K. When reality set in a couple of years later, the field settled into a large, active one, but with only the simplest of products being proposed for the following few years. (See the June 1991 special issue ofPHYSICS TODAYon high‐temperature superconductivity.)

ISSN:0031-9228    

DOI:10.1063/1.2807936

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Tennis players dream of finding Lhe perfect racket that will immediately transform them into champions. While that may be wishful thinking, it is generally agreed that today's rackets are much better than those of 20 years ago. Though they may not turn you into an instant Wimbledon winner (after all, your opponent has one too), they will clearly improve your game. There is still hope among inventors, racket manufacturers and players that a perfect racket will come along someday. If and when such a racket is developed, what will its properties be and how will it affect the game of tennis?

ISSN:0031-9228    

DOI:10.1063/1.881444

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Visually opaque media are ubiquitous in nature. While some materials are opaque because they strongly absorb visible light, others, such as loam, white paint, biological tissue and milk, are opaque because photons traveling within them are predominantly scattered rather than absorbed. A vanishingly small number of photons travel straight through such substances. Instead, light is transported through these materials in a process similar to heat diffusion (figure 1).

ISSN:0031-9228    

DOI:10.1063/1.881445

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

In our letter inviting you to this discussion, we stated: While the commitment to research and scholarship at American universities is probably greater than ever, the reputation and resources of the institutions are deteriorating. There is no doubt that more is being asked of research universities than in the past but the ability to respond is under severe stress. I'd like to begin by asking Don Langenberg if you believe the mission of the research universities is changing and, if it is, in what ways?

ISSN:0031-9228    

DOI:10.1063/1.881476

出版商:AIP    

年代:1995

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2807937

出版商:AIP    

年代:1995

数据来源: AIP