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Physics News Update
Number 606, September 25, 2002 by Phil Schewe, James Riordon, and Ben Stein

Bell Labs/Lucent Researcher Did Fabricate Data

The committee of independent scientists investigating charges of misconduct in the way certain Lucent experiments were performed or reported in scientific journals issued its report today. The committee asserts that "The evidence that manipulation and misrepresentation of data occurred is compelling." They conclude that Hendrik Schon, but not the co-authors on his many articles, falsified and fabricated data. (See Lucent press release and the full committee report.)

Polarization in the Microwave Background

Polarization in the microwave background has been measured by the Degree Angular Scale Interferometer detector (DASI), situated at the South Pole.

DASI was one of the first detector groups to see (Update 537) several peaks in the spectrum of the cosmic microwave background, the radiation originating from that era in the early universe (some 300,000 years after the big bang) when stable atoms first formed.

The modern theory of cosmology says that these microwaves received an orientation (polarization) when they emerged from the seething plasma (the "surface of last scattering") then pervading the cosmos.

DASI's measurement of a faint polarization, reported last week at the COSMO-02 meeting in Chicago, is consistent with the theoretical prediction. (See astro-ph/0209478 at arXiv.org.)

Making Bosons Act Like Fermions

In what would represent an unprecedented manipulation of matter, physicists in Germany and Austria have proposed ways of making bosons, one of the two major classes of matter, act like fermions, the other kind of matter.

Fermions (such as electrons) obey the Pauli exclusion principle: If you put multiple electrons in a box, they all must differ from each other in some way, for example by being in a different place or having a different value of a quantum property such as spin.

Bosons (such as photons and the hydrogen atom) have no such restrictions: a limitless number of them can be in the identical quantum state.

Physics is replete with examples of making the fussy fermions behave like the more easygoing bosons, thanks to the phenomena of superconductivity and superfluidity. Causing fermions to pair up, as they do in superconductors, gives the pairs the same key properties as bosons, and so they act just like bosons.

But the reverse--making the normally undiscriminating bosons act like picky fermions--has never been done before. Now, researchers (Belen Paredes, Max Planck Institute for Quantum Optics, Belen.Paredes@mpq.mpg.de) have a couple of proposals for accomplishing this.

One way, they suggest, would be to rotate a Bose-Einstein condensate. At rest, the BEC has several different low-energy levels due to different possible values of angular momentum in the atoms.

However, rotating the BEC at just the right rate causes these levels to become equal to one another in energy since the rotation will cancel out the energy gains due to angular momentum. All stuck in the low-energy well, the atoms would be forced to minimize their repulsions with one another, and they'd do this by assuming slightly different values of angular momentum, thereby acting like fermions.

Rotating BECs is now possible with lasers or mechanical devices. But to observe "fermionization" in BECs with currently obtainable rotation speeds, researchers would need to create a BEC with only a handful of atoms, say 5, instead of the typical 10,000 or so.

But in case this turns out to be infeasible, the researchers have another proposal: rotate an optical lattice, a light-based web of atom traps, containing 5 atoms in each trap. Such a situation is experimentally possible and could produce a stronger signal than that from a single BEC. (Paredes, Zoller and Cirac, Physical Review A, September 2002; also Paredes and Cirac, cond-mat/0207040 at arXiv.org)

Solar Surgery

Even some large hospitals find laser surgery too expensive. So physicists at the Blaustein Institute for Desert Research in Israel
resort to nature. They collect and focus sunlight, and then transport it in an optical fiber to a surgery theater where it can be brought to bear on tissue (see figures).

In general, the advantage of using laser light for surgery is not its coherence but high power density at adequate power levels. In this regard the solar unit can match typical surgical lasers in terms of power (8 watts) and power density (10 watts/mm2).

Jeffrey Gordon (jeff@menix.bgu.ac.il, 972-8-659-6923) and his colleagues report that tests on chicken breasts and chicken livers have been successful and that the next step will be to perform surgery on live mice with the solar optical fiber system.

The goal for the project is to deliver cheap sunlight for killing human cancers with minimally invasive procedures. (Gordon et al., Applied Physics Letters, 30 September 2002; see Dr. Gordon's homepage.)