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Dave Bacon
Benjamin Lev, University of Illinois at Urbana-Champaign (Session 2 : Friday from 10:15-10:45) Abstract. Highly magnetic atoms such as dysprosium offer the ability to create strongly correlated matter in both atomic physics and quantum optics settings. In addition, these atoms will form the key ingredient in novel devices possessing unsurpassed...
Dave Bacon
Quantum Control of Large Atomic Hyperfine Manifolds Poul Jessen, University of Arizona (Session 2 : Friday from 9:15-9:45) Abstract. Laboratory techniques to manipulate and observe ultracold atoms make these an attractive platform for testing new ideas in quantum control and measurement. I will review a series of experiments in which we have used...
Okay put notes here instead of in separate new messages. Does this update the live feed? - Dave Bacon
Cold Cesium atoms, again. Whoop. - Dave Bacon
Review and outlook by a grey beard as opposed to the talks by the young'ins. - Dave Bacon
What is the simplest control Hamiltonian sufficient for universal control of a spin J system? Not H=B \cdot J. That's just su(2). Simplest nonlinear extension works: H=B \cdot J + J_x^2. - Dave Bacon
Cs F=3 ground state manifold. Control: magnetic fields and light tuned near D1 line. - Dave Bacon
NMR-like control of magnetic fields. 200 kHz bandwidth , error < 1 percent - Dave Bacon
Drive a spin with a light shift. Electric-dipole interaction. Can get J_x^2 term. Constant of proportionality is related to rate of scattering. Can get 10 hbar x (rate of scattering) for coupling. - Dave Bacon
2007: quantum state transfer. - Dave Bacon
generating controll waveforms. Rabitz et al its a benign search landscape. - Dave Bacon
Pretty movie showing evolution. - Dave Bacon
Various experiments with fidelity close to theory. Fidelities around 0.80 to 0.90 - Dave Bacon
Next: quantum state estimation (tomography) - Dave Bacon
Control of the entire ground manifold. Merkel, Jessen Deutsch. - Dave Bacon
working on doing this (control of both F=3 and F=4 manifold.) - Dave Bacon
Designing unitary transforms by map from state preparation. - Dave Bacon
Dave Bacon
Q: Confocal microscopy helpful? Weiss: not going to say "no."
Dave Bacon
Robert asks about parallelizability of Rydberg gates. Weiss: have to be at a distance away because falls off at 1/r^3.
Dave Bacon
Okay I'm going to try to moving to posting comment under talk instead of into main feed starting with the next talk.
Dave Bacon
Summary: imaged 250 single atoms in a 3D optical lattice. The imaging causes negligible site hopping. Demonstrated site-resolved state detection. Cooling to near the vibrational ground state.
Dave Bacon
advantage 3d: good vibrational cooling is hard without tight confinement in all directions. 2d array are subsets of our 3d array. They are many more similarly near neighbors in 3D, i.e. this should help architecture.
Dave Bacon
advantage 2d: 3d site spacing is limited by depth of the field. Sites in 2D can be addressed from imaging direction.
Dave Bacon
Differences between 2d and 3d.
Dave Bacon
problem each atom has 26 pretty near neighbors. Unaddressed atoms do not feel the Rydberg interactions.
Dave Bacon
problem each atom has 26 pretty near neighbors. Unaddressed atoms do not feel the Rydberg interactions.
Dave Bacon
also Muller et all arXiv:0811.1155
Dave Bacon
state selectively excite one atom to higher state. dipole coupling to other atom and shift higher state, i.e. Jaksch et al PRL 85 2208 (2000)
Dave Bacon
Rydberg entanglement. Use crossed beams and a two-photon transition to a high rydberg states. Time 100ns, spon. em: 3x 10^{-4} / operation. heating <10^{-6} quanta/ operation. Not done yet.
Dave Bacon
Next up: two qubit gates
Dave Bacon
Lattice compacting. Important difference between using mott-insulator superfluid transition is that they can check for errors.
Dave Bacon
MEMS mirror for steering of beam. Pretty movie of beam moving around. Kim from Duke.
Dave Bacon
time: 30 micro seconds, 5x10^{-5} spontaneous emissions per operation , heating <10^{-3} quanta / operation.
Dave Bacon
microwave pulses are only resonant with the target atom.
Dave Bacon
Use qubit states that are first order B-field and circular polarization insensitive.
Dave Bacon
Use far off resonant circularly polarized light to change the energy separation of the two qubit states at the target site.
Dave Bacon
Next: single site addressability
Dave Bacon
Problem needs 10000:1 polarization purity for uncompromised cooling and pi-pulses. They are almost there.
Dave Bacon
sigma + sigma - state dependent traps. Drive sideband transitions w/o light.
Dave Bacon
Projectin cooling to get to vibrational ground state.
Dave Bacon
Optically pump to the F=4 level. Wait. Atoms decay to F=3 depends on temperature.
Dave Bacon
Hyperfine state detection. Clear away all F=4 atoms with short resonant pulse. Detect the atoms that are left.
Dave Bacon
Can get thermal hopping rate as function of X-lattice potential. 40 uK, 2 Hz, 60 uK, 0.1Hz k=Ae^{-U/T} thermal hoping, but no tunneling
Dave Bacon
In half a second identify the presence or absence of an atom at every site wtih 1x10^{-7} reliability.
Dave Bacon
Loses in middle of trap from background collisions, losses at edges due to shallowness of the trap
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