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We study the appearance of correlated many-body phenomena in an ensemble of atoms driven resonantly into a strongly interacting Rydberg state. The ground state of the Hamiltonian describing the driven system exhibits a second order quantum phase transition. We derive the critical theory for the quantum phase transition and show that it describes the(More)
Atomic matter waves, just like electromagnetic waves, can be focussed, reflected, guided, and split by the passive atom optical elements of today. However, the key for many applications of RF and light waves lies in the availability of amplifiers. These active devices allow small signal detection and have led to the development of masers and lasers. Here we(More)
We present and characterize a versatile experimental setup which allows for excitation and detection of Rydberg atoms in quantum gases. The novel concept of the setup features two charged particle detectors and eight electrical field plates inside the vacuum chamber, which allows the detection and manipulation of Rydberg atoms. The setup presented here is(More)
Symmetry-breaking interactions have a crucial role in many areas of physics, ranging from classical ferrofluids to superfluid (3)He and d-wave superconductivity. For superfluid quantum gases, a variety of new physical phenomena arising from the symmetry-breaking interaction between electric or magnetic dipoles are expected. Novel quantum phases in optical(More)
Rydberg atoms have an electron in a state with a very high principal quantum number, and as a result can exhibit unusually long-range interactions. One example is the bonding of two such atoms by multipole forces to form Rydberg-Rydberg molecules with very large internuclear distances. Notably, bonding interactions can also arise from the low-energy(More)
Imagine that a pair of coins are tossed in a black box. The box reports only one of the following three results at random: (1) the outcome of (2) the outcome of the second whether the outcomes of the two coins matched or were Quantum mechanics allows us only one incomplete glimpse of a wavefunction, but if systems can be identically prepared shadows and(More)
The coupling of electrons to matter lies at the heart of our understanding of material properties such as electrical conductivity. Electron-phonon coupling can lead to the formation of a Cooper pair out of two repelling electrons, which forms the basis for Bardeen-Cooper-Schrieffer superconductivity. Here we study the interaction of a single localized(More)
The evolution of the transverse momentum of monochromatic light entering a multimode planar waveguide at large angle is investigated. We report on oscillations of the momentum caused by the beatings between the adjacent populated modes of the waveguide and their periodic collapses and revivals. A new type of an interferometer based on this effect with(More)
Ferrofluids exhibit unusual hydrodynamic effects owing to the magnetic nature of their constituents. As magnetization increases, a classical ferrofluid undergoes a Rosensweig instability and creates self-organized, ordered surface structures or droplet crystals. Quantum ferrofluids such as Bose-Einstein condensates with strong dipolar interactions also(More)
In Rydberg atoms, at least one electron is excited to a state with a high principal quantum number. In an ultracold environment, this low-energy electron can scatter off a ground state atom allowing for the formation of a Rydberg molecule consisting of one Rydberg atom and several ground state atoms. Here we investigate those Rydberg molecules created by(More)