Time's arrows, quantum measurement
and superluminal behavior
Prefazione - Indice
Prefazione
In recent years foundational questions
of quantum mechanìcs have been yielding to experimental tests in two
principal directions: superpositions of ever larger objects ("Schrodinger
cats") and entanglement. We mention, as a specific example, experiments
of Haroche and coliaborators that both create "Schrodinger cats" and
entangle them with complex atomic states. These combine beautiful technical
advances in 
quantum
optics and in atomic physics, and are at the forefront of recent experimental
efforts in fundamental issues. Similar experiments emphasizing optical
techniques are underway in Florence. Even larger "cats" are also the
objective of current experimental efforts using Josephson junctions.
Another class offoundational questions arises in non-equilibrium
statistical mechanics and relates to famous and unresolved issues conceming
the "arrow of time." Here there is considerable interest in the community.
However, in this area there is much less activity on specific
experiments that would test the leading ideas.
There have been suggestions that these basic scientific questions
are related to one another. Some of these suggestions come with specific
expèrimental ideas. In particular, there are serious chalienges to traditional
notions of causality-chalienges that are completely consistent with
special telativity. These arise both in the classical and quantum domains,
and at this stage gedanken experiments have been proposed.
Another fascinating and intriguing topic, also related to rime measurements,
issuperluminal wave propagation. This phenomenon has already been demonstrated
experimentaliy in optical tunneling (where the group velocity exceeds
the light velocity in vacuum). It may also be present in solid state
devices. Here the experiments are difficult because of the extremely
short times involved. More recently, superluminal behavior has beenfound
in connection with non-evanescent (tunneling) waves, such as X-shaped
and complex waves in vacuum, analogous to known phenomena in acoustics.
Because of the close analogy to the wave equations that govern the motion
of waves and particles, it is natural to ask whether such behavior holds
evenfor naturaliy arising particles. These arguments are evidently of
a fundamental type but practical implications are not at all excluded.
These generai areas, ali leading to chalienges to naive notions of
causality, are attracting increasingly serious attention. The development
of experimental tests, as weli as the analysis and understanding of
those experiments already carried out, may be considered to be an important
project for these chalienging contemporary scientific ideas. This conference
brought toge"ther individuals of both a theoretical and an experimental
bent and encouraged the sharpening of theoretical issues as well discussion
of tests that could go beyond the "gedanken" stage.
The conference "Time's Arrows, Quantum Measurement and Superluminal
Behavior", was held at the Istituto Italiano per gli Studi Filosofici
in Napoli (October 3-5, 2000), and treated the topics mentioned
above. The Directors of the conference are grateful to Gerardo Marotta
and Antonio Gargano, the President and the Director, respectively,
ofthe Istutito Italiano per gli Studi Filosofici, far the hospitality
of their Institute and far the support given to the conference. Thanks
are also due to all the staff of the Institute far its coliaboration.
The Directors of the Conference
DANIELA MUGNAI
ANEDIO RANFAGNI
LAWRENCE S. SCHULMAN
