2,031 research outputs found
The Quantum Liar Experiment in Cramer's Transactional Interpretation
Cramer's Transactional Interpretation (TI) is applied to the "Quantum Liar
Experiment" (QLE). It is shown how some apparently paradoxical features can be
explained naturally, albeit nonlocally (since TI is an explicitly nonlocal
interpretation, at least from the vantage point of ordinary spacetime). At the
same time, it is proposed that in order to preserve the elegance and economy of
the interpretation, it may be necessary to consider offer and confirmation
waves as propagating in a "higher space" of possibilities.Comment: Minor editing error correcte
The 'Delayed Choice Quantum Eraser' Neither Erases Nor Delays
It is demonstrated that 'quantum eraser' (QE) experiments do not erase any
information. Nor do they demonstrate retrocausation or 'temporal nonlocality'
in their 'delayed choice' form, beyond standard EPR correlations. It is shown
that the erroneous erasure claims arise from assuming that the improper mixed
state of the signal photon physically prefers either the 'which way' or 'both
ways' basis, when no such preference is warranted. The latter point is
illustrated through comparison of the QE spatial state space with the spin-1/2
space of particles in the EPR-spin experiment.Comment: Final version, to appear in Foundations of Physic
Why the Afshar Experiment Does Not Refute Complementarity
A modified version of Young's experiment by Shahriar Afshar demonstrates
that, prior to what appears to be a ``which-way'' measurement, an interference
pattern exists. Afshar has claimed that this result constitutes a violation of
the Principle of Complementarity. This paper discusses the implications of this
experiment and considers how Cramer's Transactional Interpretation easily
accomodates the result. It is also shown that the Afshar experiment is
analogous in key respects to a spin one-half particle prepared as ``spin up
along '', subjected to a nondestructive confirmation of that
preparation, and post-selected in a specific state of spin along .
The terminology ``which-way'' or ``which-slit'' is critiqued; it is argued
that this usage by both Afshar and his critics is misleading and has
contributed to confusion surrounding the interpretation of the experiment.
Nevertheless, it is concluded that
Bohr would have had no more problem accounting for the Afshar result than he
would in accounting for the aforementioned pre- and post-selection spin
experiment, in which the particle's preparation state is confirmed by a
nondestructive measurement prior to post-selection. In addition, some new
inferences about the interpretation of delayed choice experiments are drawn
from the analysis.Comment: Final version: typos corrected; to appear in Studies in History and
Philosophy of Modern Physic
Antimatter in the Direct-Action Theory of Fields
One of Feynman's greatest contributions to physics was the interpretation of
negative energies as antimatter in quantum field theory. A key component of
this interpretation is the Feynman propagator, which seeks to describe the
behavior of antimatter at the virtual particle level. Ironically, it turns out
that one can dispense with the Feynman propagator in a direct-action theory of
fields, while still retaining the interpretation of negative energy solutions
as antiparticles.Comment: Forthcoming in a special issue of Quanta Magazine honoring Richard P.
Feynman; ed. Eliahu Cohe
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