THE BOSTON AREA PHYSICS CALENDAR
Week of January 5 - January 11, 1997
 
The Boston Area Physics Calendar is published weekly during 
the academic year by the Department of Physics and Astronomy 
at Tufts University.  You may send your announcements by 
e-mail (bapc@tuhepa.phy.tufts.edu) or FAX:(617-627-3878).  
We cannot accept announcements by telephone.  Entries should 
reach us no later than 11:00am on the Monday preceding the week 
of the event. ENTRIES RECEIVED AFTER THE DEADLINE WILL NOT 
BE PUBLISHED.

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Monday, January 6, 1997
 
No Scheduled Events

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Tuesday, January 7, 1997

No Scheduled Events

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Wednesday, January 8, 1997
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Wednesday, January 8, 12:00 p.m.

Boston University
Particles and Fields Seminar
Physics Research Building, Room 593
``Search for Neutrino Mass at Super-Kamiokande''
DR. SOO-BONG KIM
Boston University

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Wednesday, January 8, 5:00 p.m.

Harvard University/Center for Astrophysics
Joint Atomic Physics Seminar
Jefferson Laboratory, Room 356
``A New Look at the Phase in the WKB Wave Function''

Abstract:

The famous ``connection formula" relating WKB wave functions on
 the allowed and forbidden sides of a classical turning
 point tells us that the WKB wave function loses a phase $\pi/2$ when
 reflected by a smooth potential. The Maslov index $\mu$ counting such
 reflections appears in semiclassical quantization formulae, e.g. in
$$\int_a^bp(x)dx=\left(n+{\mu\over 4}\right)\pi\hbar$$
 for a particle in one dimension oscillating between two classical
 turning points $a$ and $b$ ($p(x)$ is the local classical momentum).

The conditions for applicability of the WKB approximation are often
 well fulfilled away from the short-wave limit --- even up to the limit
 of very long waves --- if we exclude the immediate vicinity of
 classical turning points. In such cases, the accuracy of the WKB
 approximation can be dramatically improved by allowing the phase loss
 due to reflection at a classical turning point to be a nonintegral
 multiple of $\pi/2$; this amounts to allowing nonintegral Maslov indices.
 The appropriate phase loss generally varies smoothly from the value
 $\pi/2$ in the short-wave limit to the value $\pi$ in the long-wave limit.
 For potentials proportional to $1/x^2$ it is independent of energy and the
 resulting WKB wave function is more accurate by two orders in $1/(kx)$
 ($k$ is the wave number) than the conventional WKB wave function obtained
 via phase loss $\pi/2$ and the Langer-modified potential. Various further
 examples of the usefulness of the concept of nonintegral Maslov indices
 are given. [Phys. Rev. Lett. {\bf 76} (1997) 4869.] 

DR. HARALD FRIEDRICH
Technische Universitat Munchen
Tea will be served at 4:30 p.m.

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Thursday, January 9, 1997
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Thursday, January 9, 4:00 p.m.

Harvard-Smithsonian Center for Astrophysics
Scientific Colloquium
60 Garden Street (Phillips Auditorium)
``Planets Orbiting Sun-Like Stars''

Abstract:

Eight planetary companions have been detected by the accelerations of the
host stars.  Most were detected by stellar doppler measurements with
a precision of 3 m/s.  Some of the new planets have
properties similar to planets in our Solar System.  However, several are
more massive than Jupiter, and four orbit their host star closer than 0.1
AU.  Three planets reside in non-circular orbits.  Augmentation of
existing theories of planet formation may account for their
diverse properties.  The occurrence rate of true Solar-System
analogs remains a mystery.  During the upcoming 5 years, several new
techniques for detection of extrasolar planets will be tested, including use
of the Keck 10-meter telescope, MMT adaptive optics, and interferometry.

DR. GEOFFREY MARCY
San Francisco State University
Adjunct Professor, U.C. Berkeley, California

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Friday, January 10, 1997

No Scheduled Events 

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A Friendly Reminder:

The Deadline for the January 12-January 18, 1997 Issue is:

TUESDAY, December 31, 1996 at 11:00 a.m.

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