Dear quanta,
These two talks should be of interest to many of us.
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Thurs 2/5, 4pm in 10-250
Markus Oberthaler (University of Heidelberg)
Quantum metrology with Bose Einstein Condensates
One aspect of metrology, the science of measurement, is the
exploration of the ultimate precision limit. It is known for quite
some time that the new possibilities in quantum mechanics allow the
surpassing of the ultimate classical precision limit given by counting
statistics. Quantum metrology is about the exploration of these new
limits. The goal is the generation and characterization of useful
quantum mechanical resources for going beyond the classical precision
limits. Since the gain in precision is intimately connected to quantum
entanglement in many particle systems these investigations are also
interesting from the fundamental point of view.
In this colloquium I will discuss in detail how Bose Einstein
condensates can be used to generate entangled many particle states
which push atom interferometry beyond the classical limits. I will
use the system of two component atomic condensates as a model system
for explaining how quantum correlations arise and how they can be used
for improved estimation of a phase shift in an atom interferometer.
The simplest form of useful many particle quantum states are spin
squeezed states which can be classified as Gaussian states. I will
also report on the latest results revealing that Bose Einstein
condensates make it possible to generate deterministically
non-gaussian states. The experimental extraction of a bound of the
quantum Fisher information implies that these states also surpass the
classical limits of the phase estimation precision.
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Fri 2/6, 1:30 in 6C-442
Brian Swingle (Stanford University)
Einstein's Equations From Entanglement
I will propose a mechanism whereby a dynamical geometry obeying
Einstein's equations emerges holographically from entanglement in
certain quantum many-body systems. As part of this broader story I
will discuss in particular two crucial results: one establishing a
geometric representation of entanglement in the vacuum state of a wide
class of (lattice regulated) quantum field theories and one showing
how the equivalence principle of gravity is encoded in the
universality of entanglement. I will also briefly indicate how the
first result opens the door to solving previously intractable strongly
interacting models of relevance for experiments in the solid state and
elsewhere. Thus I will argue that the fundamental physics of
entanglement provides a window into non-perturbative quantum field
theory and quantum gravity.
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