4 research outputs found
Mesoscopic Rydberg Gate based on Electromagnetically Induced Transparency
We demonstrate theoretically a parallelized C-NOT gate which allows to
entangle a mesoscopic ensemble of atoms with a single control atom in a single
step, with high fidelity and on a microsecond timescale. Our scheme relies on
the strong and long-ranged interaction between Rydberg atoms triggering
Electromagnetically Induced Transparency (EIT). By this we can robustly
implement a conditional transfer of all ensemble atoms among two logical
states, depending on the state of the control atom. We outline a many body
interferometer which allows a comparison of two many-body quantum states by
performing a measurement of the control atom.Comment: published versio
Two-dimensional array of microtraps with atomic shift register on a chip
Arrays of trapped atoms are the ideal starting point for developing registers
comprising large numbers of physical qubits for storing and processing quantum
information. One very promising approach involves neutral atom traps produced
on microfabricated devices known as atom chips, as almost arbitrary trap
configurations can be realised in a robust and compact package. Until now,
however, atom chip experiments have focused on small systems incorporating
single or only a few individual traps. Here we report experiments on a
two-dimensional array of trapped ultracold atom clouds prepared using a simple
magnetic-film atom chip. We are able to load atoms into hundreds of tightly
confining and optically resolved array sites. We then cool the individual atom
clouds in parallel to the critical temperature required for quantum degeneracy.
Atoms are shuttled across the chip surface utilising the atom chip as an atomic
shift register and local manipulation of atoms is implemented using a focused
laser to rapidly empty individual traps.Comment: 6 pages, 4 figure
Quantum kinetic Ising models
We introduce a quantum generalization of classical kinetic Ising models,
described by a certain class of quantum many body master equations. Similarly
to kinetic Ising models with detailed balance that are equivalent to certain
Hamiltonian systems, our models reduce to a set of Hamiltonian systems
determining the dynamics of the elements of the many body density matrix. The
ground states of these Hamiltonians are well described by matrix product, or
pair entangled projected states. We discuss critical properties of such
Hamiltonians, as well as entanglement properties of their low energy states.Comment: 20 pages, 4 figures, minor improvements, accepted in New Journal of
Physic
A Rydberg Quantum Simulator
Following Feynman and as elaborated on by Lloyd, a universal quantum
simulator (QS) is a controlled quantum device which reproduces the dynamics of
any other many particle quantum system with short range interactions. This
dynamics can refer to both coherent Hamiltonian and dissipative open system
evolution. We investigate how laser excited Rydberg atoms in large spacing
optical or magnetic lattices can provide an efficient implementation of a
universal QS for spin models involving (high order) n-body interactions. This
includes the simulation of Hamiltonians of exotic spin models involving
n-particle constraints such as the Kitaev toric code, color code, and lattice
gauge theories with spin liquid phases. In addition, it provides the
ingredients for dissipative preparation of entangled states based on
engineering n-particle reservoir couplings. The key basic building blocks of
our architecture are efficient and high-fidelity n-qubit entangling gates via
auxiliary Rydberg atoms, including a possible dissipative time step via optical
pumping. This allows to mimic the time evolution of the system by a sequence of
fast, parallel and high-fidelity n-particle coherent and dissipative Rydberg
gates.Comment: 8 pages, 4 figure