摘要:

Recent experimental results by Metz, Jolie and collaborators have led to renewed interest in the notion of dynamical supersymmetry in fermion many-body systems. By considering the general problem of constructing a boson-fermion realization for Lie algebras with generators expressed in terms of fermion and bifermion operators, also when favored pairs dictate the structure of collective bosons, we demonstrate that dynamical “supersymmetry without bosons” can indeed emerge in a fermion systemwithout any Pauli Violations. Our construction of the general realization utilizes the identification of a physical subspace and allows one to identify the images of single particle transfer operators uniquely, unlike the situation in phenomenological applications of dynamical supersymmetry. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1337728

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Deformed Heisenberg algebra with reflection appeared in the context of Wigner’s generalized quantization schemes underlying the concept of parafields and parastatistics of Green, Volkov, Greenberg and Messiah. We review the application of this algebra for the universal description of ordinary spin-jand anyon fields in2+1dimensions, and discuss the intimate relation between parastatistics and supersymmetry. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1337729

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

We present a review of the spin and statistics of topological geons, particles in3+1quantum gravity. They can have half-odd-integral spin and fermionic statistics and since the underlying gravitational field is tensorial and bosonic, this is an example of “emergent” non-trivial spin and statistics as displayed by familiar non-gravitating objects such as skyrmions. We give the topological background and show that in a “canonical” quantization of gravity there is no spin-statistics correlation for topological geons. Allowing the topology of space to change, for example in a sum-over-histories approach, raises the possibility that a spin-statistics correlation can be recovered for geons. We review a conjectured set of rules powerful enough to give such a spin-statistics correlation for all topological geons. These would appear to rule out the possibility of parastatistics and may rule out spinorial and fermionic geons altogether. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1337730

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

We study properties of a scalar quantum field theory on noncommutative space-times. We show that field theories on a noncommutative plane have ultraviolet divergences, while the theory on a noncommutative cylinder is ultraviolet finite. Thus, ultraviolet behavior of a field theory on noncommutative spaces is sensitive to the topology of the space-time, namely to its compactness, We present general arguments for the case of higher space-time dimensions and as well discuss the implication of the noncommutativity on the spin-statistics theorem. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1337731

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

We discuss theoretical models and experimental data that shed light on possible small violations of the spin-statistics relation for photons. Particular emphasis is given to our recent experimental search for non-symmetric photon states, using atomic two-photon transitions. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1337732

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

A review is given of experiments that have been used to infer an upper bound on the degree(&bgr;2)to which the symmetrization postulate might be violated in nature. A proposed grouping of the experiments into seven different categories is put forth, based on different conceptual difficulties associated with interpreting them. Some comments are made about the strengths and weaknesses of representative experiments from several of the categories. It is suggested that there may be a considerable body of existing experimental data that could be analyzed to infer additional limits on SP-violation; as an example of this I consider the suppression of molecular recombination in spin-polarized atomic hydrogen by strong magnetic fields. While this article is limited to experiments involving fermions, an extensive bibliography on both theory and experiments related to the spin-statistics connection in general is referred to. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1337733

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

The interpretation in terms of CP violation of the experimental results concerning the neutral kaon system requires, in general, assumptions about the validity of quantum mechanics, about the coherence of the wave function and of its behavior under particle exchange. A few examples are discussed where these assumptions can be tested. An update is also given of the present experimental situation concerning in particular direct CP violation in two-pion decay. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1337734

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

I present the idea underlying the experiments on molecules to test the validity of the symmetrization postulate of quantum mechanics and the spin-statistics connection for nuclei. I describe in some detail recent experiments onO2andCO2molecules and show that these should be considered as tests of the spin-statistics connection for the spin-0 oxygen nuclei. I discuss the possibility of new experiments to test the spin-statistics connection and the symmetrization postulate. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1337735

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

We review some observed consequences of the Pauli principle in ultrahigh resolution spectroscopy of polyatomic molecules with several identical bosonic or fermionic nuclei. An important feature is the link with parity. Several possible tests of the symmetrization postulate come out of this analysis and we discuss in more detail an experiment which is presently conducted withOsO4in our laboratory. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1337736

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

In this contribution we describe our current efforts at Berkeley to improve upon a limit on Bose-Einstein statistics violation for photons obtained earlier (D. P. DeMille, D. Budker, N. Derr, and E. Deveney,Phys. Rev. Lett.83(20), 1378 (1999)). The principle differences between the new and the previous experiments are the use of a narrow-band cw laser, an atomic beam, a different transition in atomic Ba, and possibly a different detection technique. We also discuss the ultimate limits that one can hope to obtain with this degenerate two-photon transition technique. Some potential conceptual difficulties with the interpretation of this experiment and the ways to avoid them are discussed as well. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1337737

出版商:AIP    

年代:1900

数据来源: AIP