ITAMP Talks at the DPG Spring Meeting (Stuttgart, Germany)

Demler, Eugene
SYRA 2.4 Supersymmetry in Rydberg-dressed lattice fermions

Laumann, Chris
Q 19.1 Long-range quantum gates for nitrogen-vacancy defect centers in diamond

Lukin, Mikhail
Q 7.7 Robustness of Topological Operations with Ultracold Atoms
Q 19.1 Long-range quantum gates for nitrogen-vacancy defect centers in diamond
SYRA 1.4 Electromagnetically Induced Transparency in Strongly Interacting Rydberg Gases
SYRA 2.4 Supersymmetry in Rydberg-dressed lattice fermions

Rittenhouse, Seth
SYRA 2.3 Electric field impact on ultra-long-range triatomic polar Rydberg molecules

Sadeghpour, Hossein
Q 62.1 A homonuclear polar molecule
SYRA 2.3 Electric field impact on ultra-long-range triatomic polar Rydberg molecules

Weimer, Hendrik
Q 19.1 Long-range quantum gates for nitrogen-vacancy defect centers in diamond
SYRA 2.4 Supersymmetry in Rydberg-dressed lattice fermions

ITAMP Talks APS March March 2012

	Aspuru-Guzik, Alan V28.00004 Nonradiative lifetimes in intermediate band materials -- absence of lifetime recovery L35.00010 The derivative discontinuity in density functional theory from an electrostatic description of the exchange and correlation potential V48.00012 Accessing exciton transport in light-harvesting structures with plasmonic nanotip V34.00010 How much information do ultrafast spectra contain? The case for ultrafast quantum process tomography T30.00006 Algorithmic Quantum Cooling J34.00003 2-Dimensional Fluorescence Spectroscopy: Determining the Temperature-Dependent Conformations of Porphyrin Dimers and Nucleic Acids L36.00002 Study of excitonic energy transport in thin-film J-aggregates W41.00002 Absence of quantum oscillations in electronic excitation transfer in the Fenna-Matthews-Olson complex J30.00005 Quantum simulator of an open quantum system using superconducting qubits: exciton transport in photosynthetic complexes J34.00002 Conformation of self-assembled porphyrin dimers in liposome vesicles by phase-modulation 2D fluorescence spectroscopy X17.00004 Plasmonic nanotips for spectroscopy with nanometer-scale resolution W35.00009 Applying state-of-the-art signal processing to time-dependent density functional theory B7.00002 The Harvard Clean Energy Project: High-throughput screening of organic photovoltaic materials using cheminformatics, machine learning, and pattern recognition B7.00001 The Harvard Clean Energy Project: High-throughput screening of organic photovoltaic materials using first-principles electronic structure theory V35.00004 Time-dependent density functional theory for open quantum systems Cappellaro, Paola K1.00260 Composite-pulse magnetometry in the solid-state K1.00308 Perfect mixed state quantum transport in correlated spin networks Demler, Eugene J4.00001 Non Equilibrium Quantum Criticality: an intuitive approach Z4.00003 Collective mode of an impurity and a Tonks-Girardeau gas D4.00010 Clustering of cold polar molecules in arrays of one-dimensional tubes V4.00001 Doublon production rate by optical lattice modulation for strongly correlated Fermionic atoms D4.00007 Tunable Superfluidity with Ultracold Polar Molecules on quasi-1D Optical Lattices J4.00003 Stability of Counterflow Superfluidity A32.00015 Photo-induced quantum Hall insulators without Landau levels D4.00006 Quantum Magnetism with Polar Molecules: Tunable Generalized $t$-$J$ Model A8.00011 Emergence and lifting of frustration for dipolar molecules Feist, Johannes  D10.00005 Accessing correlated electron motion on the attosecond timescale V48.00012 Accessing exciton transport in light-harvesting structures with plasmonic nanotip X17.00004 Plasmonic nanotips for spectroscopy with nanometer-scale resolution V4.00013 A Quantum Plasmonic Circuit for Cold Atoms A4.00003 A nanoscale quantum interface for single atoms Laumann, Chris  K1.00283 Topologically Protected Quantum State Transfer in a Chiral Spin Liquid D29.00009 Long-range quantum gates using dipolar crystals  T24.00005 Microscopic Disorder-Based model for non-Abelian Quasi-Particles in $\nu=5/2$ FQH states

Lemeshko, Mikhail
K1.00334 Sensitive imaging of electromagnetic fields with cold polar molecules

Lukin, Mikhail 
D4.00007 Tunable Superfluidity with Ultracold Polar Molecules on quasi-1D Optical Lattices
A30.00010 Towards Probing Living Cell Function with NV Centers in Nanodiamonds
D4.00003 Altering Photon Statistics using Strong Rydberg Interactions
D4.00002 Towards single-photon optical nonlinearities using cold Rydberg atoms
D4.00006 Quantum Magnetism with Polar Molecules: Tunable Generalized $t$-$J$ Model
A30.00006 Decoherence imaging of spin ensembles by a scannable single nitrogen-vacancy center in diamond
V48.00012 Accessing exciton transport in light-harvesting structures with plasmonic nanotip
A4.00003 A nanoscale quantum interface for single atoms
A4.00001 A Light-Matter Interface with NV Centers
V4.00013 A Quantum Plasmonic Circuit for Cold Atoms
A4.00002 Probing the motion of a mechanical resonator via coherent coupling to a single spin qubit
D29.00007 Room temperature solid-state quantum bit with second-long memory
D29.00005 Optimizing the resolution and the sensitivity of a scanning NV magnetometer
D29.00003 Quantum interference of single photons from two remote Nitrogen-Vacancy centers in diamond
D29.00010 Magnetic imaging of a single electron spin using a scanning NV magnetometer under ambient conditions
X17.00004 Plasmonic nanotips for spectroscopy with nanometer-scale resolution
W41.00003 Progress Towards Room-Temperature Electron Spin Detection in Biological Systems
D29.00013 Spectroscopy of composite solid-state spin environments for improved metrology with spin ensembles
B4.00005 Coupling a single spin in diamond to the quantum motion of a mechanical cantilever
L10.00003 Quantum optics with solid-state atom-like systems
A30.00005 Cooling Nuclear Spins in Diamond via Dark State Spectroscopy
A30.00003 Quantum Optics with Spins and Photons in Diamond

Mathy, Charles
Z4.00003 Collective mode of an impurity and a Tonks-Girardeau gas

Onofrio, Roberto
B1.00002 Four techniques to achieve deeper Fermi degeneracy in Fermi-Bose mixtures
B1.00003 Optimized sympathetic cooling of atomic mixtures via fast adiabatic strategies

Rittenhouse, Seth
D4.00011 A dielectric superfluid of polar molecules

Safavi-Naini
A. A4.00010 An ab-initio microscopic theory of anomalous heating in planar ion traps
D4.00013 Paired Phases of Dipoles in a Bilayer System

Sadeghpour, H.R. 
A4.00010 An ab-initio microscopic theory of anomalous heating in planar ion traps
D4.00013 Paired Phases of Dipoles in a Bilayer System

Weimer, Hendrik
K1.00283 Topologically Protected Quantum State Transfer in a Chiral Spin Liquid

Yelin, Susanne
A30.00005 Cooling Nuclear Spins in Diamond via Dark State Spectroscopy

ITAMP/B2 Winter Graduate School on AMO Physics, Jan 8-20, 2012

The 1st morning session of the school went quite well. There were talks by Jun Ye (JILA) on control of light; how ultrafast laser pulses could be used to produce ultrastable frequency combs, and how different frequency scales, from UVU could be referenced to IR, a preview for his 2nd lecture tomorrow on controlling atomic matter with light. The 2nd talk was given by Pierre Meystre (replacing Mette Gaarde who could not be here) on cooling of optomechanical systems. This emerging subject of inquiry in AMO sciences has mushroomed over the last few years b/c a number of groups have succeeded in bringing the center of mass motion of nearly macroscopic objects to the quantum ground level. Pierre described what could be investigated with ground state objects, ala beyond ground state cooling.

The afternoon talks are now being given by Ivan Deutsch (UNM) and Han Pu (Rice). Han is giving a rigorous account of theory of laser cooling.

The students appear enthusiastic and engage the faculty with questions. The settings are beautiful- the mornings are quite and a bit chilly, and warming day hours which follow. The accommodations are first rate and comfortable.

A homonuclear molecule with a permanent dipole moment

Traditional wisdom tells us that homonuclear molecules cannot have a permanent dipole moment. However, when one of the atoms in a diatomic molecule is in a highly excited Rydberg state, the exchange symmetry between the two atoms is broken. In a new article published today in Science [1], ITAMP postdoc Seth Rittenhouse and scientist Hossein Sadeghpour in collaboration with groups from the Max-Planck-Institut für Physik komplexer Systeme and the University of Stuttgart, we describe the first direct measurement of a homonuclear, diatomic molecule with a permanent electric dipole moment.

Giant Rydberg molecules, first predicted over a decade ago [2], can bond courtesy of frequent scattering of the Rydberg electron off of a ground state atom. These molecules were later observed spectroscopically in s-wave dominated states [3]. However, because the electronic distribution was assumed to be isotropic, it was thought that this type of molecule would not have any polar behavior.

In our new work, we show that in truth a very small amount of the so-called "trilobite" state is admixed to the molecular electronic state resulting in appreciable dipole moments (on the order od 1 Debye). This prediction is born out by the observation of a linear Stark shift a small fields in high precision spectroscopic measurements of the Stark map of homonuclear rubidium Rydberg molecules.

(a) The electron density for a Giant homonuclear molecule is show in cylindrical coordinates. (b) The trilobite-like electron density is shown after the isotropic amplitude has been subtracted. In both figures the Rb Rydberg core is at z = ρ = 0, the while the ground state atom is located z = 1900 atomic units (figure from Ref. [1]).


References:
[1] W. Li, T. Pohl, J. M. Rost, S. T. Rittenhouse, H. R. Sadeghpour, J. Nipper, B. Butscher, J. B. Balewski, V. Bendkowsky, R. Low and T. Pfau, Science 334, 1110 (2011).

[2] H. R. Sadeghpour, A. S. Dickinson and C. H. Greene, Phys. Rev Lett. 85, 2458 (2000).

[3] V. Bendkowsky et al., Nature 458, 1005 (2009).

Watching correlated electron motion with attosecond pulses

In a recent paper published in Physical Review Letters, we propose a new approach to observe the correlated motion of two electrons on the attosecond timescale. In this pump-probe setup, two identical extreme-ultraviolet light pulses with a duration of just a few hundred attoseconds (1 as = 10^-18 s) are sent onto a helium atom. We expect that with the continuing development of intense attosecond pulses, this kind of experiment could be performed in the next few years. Most current experiments use a strong few-femtosecond infrared field in combination with an extreme-ultraviolet attosecond pulse. These rely on highly nonlinear effects to attain subcycle time resolution within the infrared pulse. In contrast to such setups, the wave packet dynamics are not modified by the fields when using two extreme ultraviolet pulses. The proposed measurement would thus be one of the first experiments to directly observe field-free correlated electron dynamics in atoms on their natural attosecond timescale.

In our proposed setup, the first (pump) pulse excites a coherent wave packet of doubly excited states. These are prototypical examples of highly correlated states where the two electrons influence each other strongly. After letting this wave packet evolve for some time, the second (probe) pulse ejects both electrons. By repeating the sequence many times with different time delays between the two pulses, a "movie" of the doubly excited wave packet can be created frame by frame. 

In the paper, we show that by measuring only one of the two ejected electrons and counting only those electrons within a specific energy interval, it is possible to gain direct access to an observable related to the dynamics of both electrons: the distance between them at the moment of ionization.

There is one further problem to overcome: Both steps in the pump-probe sequence only occur with small probabilities. Both in double excitation (pump) and in double ionization (probe), absorption of one photon has to lead to a two-electron transition. As a photon only "talks" to one electron directly, these two-electron transitions are quite unlikely. We show that one can exploit quantum interference to increase the magnitude of the signal: Since the pump and probe pulses are identical, absorption of two photons from just one of them leads to the same final states as absorption of one photon from each pulse. This "direct" pathway, where each photon ejects one electron, is orders of magnitude more likely than the more interesting pump-probe pathway. However, it does not represent an incoherent background that masks the signal of interest. Instead, it provides a coherent reference pathway that the pump-probe pathway through the doubly excited states interferes with. The amplitude of the interference term is about a hundred times larger than the magnitude of the pump-probe signal by itself, thus providing an experimentally more accessible signal.

Reference: J. Feist, S. Nagele, C. Ticknor, B. I. Schneider, L. A. Collins, and J. Burgdörfer, Phys. Rev. Lett. 107, 093005 (2011)

What is causing trapped ions to heat up? In an ion trap, electrodes (shown here in gold) produce electric fields that confine the ion (green sphere) to a small volume. Randomly fluctuating dipoles on the surface of these electrodes generate electric field noise. The dipoles form when single atoms adsorb on the metal surface. Vibrations (phonons) in the metal cause the dipoles (purple arrows) to fluctuate. Ions trapped in the vicinity of the metal surface sense these electric field changes and heat up.

Viewpoint

Atomic and Molecular Physics

Physics 4, 66 (2011)DOI: 10.1103/Physics.4.66

All that is gold does not glitter

Nikos Daniilidis and Hartmut HäffnerDepartment of Physics, University of California, Berkeley, CA 94720-7300, USA

Published August 22, 2011

A microscopic model offers new insight into a pernicious source of electric field noise in ion traps.

More here ....

A Viewpoint on:

Microscopic model of electric-field-noise heating in ion traps

A. Safavi-Naini, P. Rabl, P. F. Weck, and H. R. Sadeghpour

Phys. Rev. A 84, 023412 (2011) – Published August 22, 2011

Download PDF (free)

Artificial Atoms Can Do More Than Atoms

In a recently published work in Physical Review Letters, we have shown that artificial atoms made of a large number of single atoms can exhibit superior properties compared to their individual counterparts. Our results provide a way to novel applications in photonic devices used for quantum communication and quantum metrology.

In our work, we investigate an ensemble of strongly interacting atoms as found in Rydberg atoms or semiconductor quantum dots. The interaction of these systems with light can be described by an artificial atom with only two energy levels. However, when applying controlled noise to the system, this approximation breaks down and additional energy levels have to be taken into account. If a light beam is then sent through the system, these additional levels result in exactly one photon being removed from the beam. This single photon absorption process can be used in number resolving photon counters or for the creation of non-classical states of light.

Reference: J. Honer, R. Löw, H. Weimer, T. Pfau, H. P. Büchler, Phys. Rev. Lett. 107, 093601 (2011).
See also: Synopsis in Physics