11,606 research outputs found

### Many-Body Physics with Ultracold Gases

This article reviews recent experimental and theoretical progress on
many-body phenomena in dilute, ultracold gases. Its focus are effects beyond
standard weak-coupling descriptions, like the Mott-Hubbard-transition in
optical lattices, strongly interacting gases in one and two dimensions or
lowest Landau level physics in quasi two-dimensional gases in fast rotation.
Strong correlations in fermionic gases are discussed in optical lattices or
near Feshbach resonances in the BCS-BEC crossover.Comment: revised version, accepted for publication in Rev. Mod. Phy

### Many-body physics of intersubband polaritons

Intersubband polaritons are light-matter excitations originating from the
strong coupling between an intersubband quantum well electronic transition and
a microcavity photon mode. In this paper we study how the Coulomb
electron-electron interaction and the Pauli saturation of the electronic
transitions affect the physics of intersubband polaritons. We develop a
microscopic many-body theory for the physics of such composite bosonic
excitations in a microcavity-embedded two-dimensional electron gas. As a first
application, we calculate the modification of the depolarization shifts and the
efficiency of intersubband polariton-polariton scattering processes

### Shape-Invariance and Many-Body Physics

Recent developments in the study of shape-invariant Hamiltonians are briefly
summarized. Relations between certain exactly solvable problems in many-body
physics and shape-invariance are explored. Connection between Gaudin algebras
and supersymmetric quantum mechanics is pointed out.Comment: To appear in the proceedings of "Symmetries in Nuclear Structure,
Ettore Majorana Centre, Erice - Sicily, Italy, March 23-29, 2003"; 10 pages
of Latex outpu

### Introducing many-body physics using atomic spectroscopy

Atoms constitute relatively simple many-body systems, making them suitable
objects for developing an understanding of basic aspects of many-body physics.
Photoabsorption spectroscopy is a prominent method to study the electronic
structure of atoms and the inherent many-body interactions. In this article the
impact of many-body effects on well-known spectroscopic features such as
Rydberg series, Fano resonances, Cooper minima, and giant resonances is
studied, and related many-body phenomena in other fields are outlined. To
calculate photoabsorption cross sections the time-dependent configuration
interaction singles (TDCIS) model is employed. The conceptual clearness of
TDCIS in combination with the compactness of atomic systems allows for a
pedagogical introduction to many-body phenomena.Comment: 15 pages, 6 figures, 1 table. The following article has been accepted
by American Journal of Physic

### Many Body Physics with Coupled Transmission Line Resonators

We present the Josephson junction intersected superconducting transmission
line resonator. In contrast to the Josephson parametric amplifier, Josephson
bifurcation amplifier and Josephson parametric converter we consider the regime
of few microwave photons. We review the derivation of eigenmode frequencies and
zero point fluctuations of the nonlinear transmission line resonator and the
derivation of the eigenmode Kerr nonlinearities. Remarkably these
nonlinearities can reach values comparable to Transmon qubits rendering the
device ideal for accessing the strongly correlated regime. This is particularly
interesting for investigation of quantum many-body dynamics of interacting
particles under the influence of drive and dissipation. We provide current
profiles for the device modes and investigate the coupling between resonators
in a network of nonlinear transmission line resonators.Comment: submitted to the proceedings of the CEWQO 2012 conferenc

### Multi-Agent Complex Systems and Many-Body Physics

Multi-agent complex systems comprising populations of decision-making
particles, have many potential applications across the biological,
informational and social sciences. We show that the time-averaged dynamics in
such systems bear a striking resemblance to conventional many-body physics. For
the specific example of the Minority Game, this analogy enables us to obtain
analytic expressions which are in excellent agreement with numerical
simulations.Comment: Accepted for publication in Europhysics Letter

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