We demonstrate sympathetic sideband cooling of a 40CaH+ molecular ion co-trapped with a 40Ca+ atomic ion in a linear Paul trap. Both axial modes of the two-ion chain are simultaneously cooled to near the ground state of motion. The center of mass mode is cooled to an average quanta of harmonic motion n ¯ COM = 0.13 ± 0.03 ?> , corresponding to a temperature of 12.47 ± 0.03 &mgr; K ?> . The breathing mode is cooled to n ¯ BM = 0.05 ± 0.02 ?> , corresponding to a temperature of 15.36 ± 0.01 &mgr; K ?> .

: State-of-the art micro-fabricated ion traps for quantum information research have grown to incorporate upwards of a hundred control electrodes. In the typical architecture, a surface-electrode ion trap is fabricated on a thin chip that sits atop an industry standard CPGA carrier. To supply DC potentials for each electrode, pads on the CPGA are wirebonded to pads on the trap chip, while on-chip surface capacitors suppress pickup from the RF trapping fields. For large numbers of electrodes, the physical area taken up by these wirebonds and filter capacitors present significant constraints for ion trap design and operation. We report here on the development and successful testing of a new architecture for microfabricated ion traps, built around ball-grid array (BGA) connections and trench capacitors. In the BGA trap, through-substrate vias (TSVs) are used to bring electrical signals from the back side of the trap die to the top side. Gold-ball bump bonds connect the back side of the trap die to a separate interposer for signal routing from the CPGA carrier. Trench capacitors fabricated into the trap die eliminate the need for surface capacitors, reducing the trap die area by 30x.

The masses of single molecular ions are nondestructively measured by cotrapping the ion of interest with a laser-cooled atomic ion, (40)Ca(+). Measurement of the resolved sidebands of a dipole forbidden transition on the atomic ion reveals the normal-mode frequencies of the two ion system. The mass of two molecular ions, (40)CaH(+) and (40)Ca(16)O(+), are then determined from the normal-mode frequencies. Isotopes of Ca(+) are used to determine the effects of stray electric fields on the normal mode measurement. The future use of resolved sideband experiments for molecular spectroscopy is also discussed.

for Workshop Ion Trap Technology, February 16 – 17, 2011, NIST Quantum Interference and Superradiance from entangled Atoms R. Wiegner, J. von Zanthier, G. S. Agarwal Institut für Optik, Information und Photonik, Universität Erlangen-Nürnberg, Erlangen, Germany Department of Physics, Oklahoma State University, Stillwater, Oklahoma, USA Recent years have seen the ability to create large varieties of entangled states among radiating particles. The question then arises how the optical properties of such entangled photon sources differ from a radiating source in a separable state. We investigate fundamental processes like emission and scattering of radiation from entangled systems. We show how entanglement can lead to enhancement of basic processes by explicitly taking into account the various quantum paths. We relate enhancement to quantum interference of multiple photon pathways. Our work also shows how Dicke super radiance from states with zero dipole moment can be understood as interference phenomena. Generation of all symmetric as well as all total angular momentum eigenstates in photonic or matter qubits J. von Zanthier, A. Maser, R. Wiegner, U. Schilling, C. Thiel, T. Bastin, E. Solano G. S. Agarwal Institut für Optik, Information und Photonik, Universität Erlangen-Nürnberg, Erlangen, Germany Institut de Physique Nucléaire, Atomique et de Spectroscopie, Université de Liège, Liège, Belgium Departamento de Química Física, Universidad del País Vasco–Euskal Herriko Unibertsitatea, Bilbao, Spain Department of Physics, Oklahoma State University, Stillwater, Oklahoma, USA We propose a method for the generation of a large variety of entangled states, encoded in the polarization degrees of freedom of N photons, within the same experimental setup. Starting with uncorrelated photons, emitted from N arbitrary single photon sources, and using linear optical tools only, we demonstrate the creation of all symmetric states, e.g., GHZand W-states, as well as all symmetric and non-symmetric total angular momentum eigenstates of the N qubit compound [1]. Modifying slightly the multiphoton detection technique and using Λ-level atoms as single photon sources, the same classes of states can also be generated among the long-lived ground state qubits of N massive particles [2-4]. Amongst others, the schemes enable to generate all canonical states representing all possible entanglement families of symmetric states inequivalent under SLOCC as recently defined in [5]. [1] A. Maser, R. Wiegner, U. Schilling, C. Thiel, and J. von Zanthier, Phys. Rev. A 81, 053842 (2010) [2] C. Thiel, J. von Zanthier, T. Bastin, E. Solano, and G. S. Agarwal, Phys. Rev. Lett. 99, 193602 (2007). [3] T. Bastin, C. Thiel, J. von Zanthier, L. Lamata, E. Solano, G. S. Agarwal, Phys. Rev. Lett. 102, 053601 (2007). [4] A. Maser, U. Schilling, T. Bastin, E. Solano, C. Thiel, and J. von Zanthier, Phys. Rev. A 79, 033833 (2009) [5] T. Bastin, S. Krins, P. Mathonet, M. Godefroid, L. Lamata, and E. Solano, Phys. Rev. Lett. 103, 070503 (2009).

The coupled motion of ions in a radiofrequency trap has been used to connect the frequency-dependent laser-induced heating of a sympathetically cooled spectroscopy ion with changes in the fluorescence of a laser-cooled control ion. This technique, sympathetic heating spectroscopy, is demonstrated using two isotopes of calcium. In the experiment, a few scattered photons from the spectroscopy ion are transformed into a large deviation from the steady-state fluorescence of the control ion. This allows us to detect an optical transition where the number of scattered photons is below our fluorescence detection limit. Possible applications of the technique to molecular ion spectroscopy are briefly discussed.

Trapped laser-cooled atomic tons are a new tool for understanding cold molecular ions. The atomic ions not only sympathetically cool the molecular ions to millikelvin temperatures, but the bright atomic ion fluorescence can also serve as a detector of both molecular reactions and molecular spectra. We are working towards the detection of single molecular ion spectra by sympathetic heating spectroscopy. Sympathetic heating spectroscopy uses the coupled motion of two trapped ions to measure the spectra of one ion by observing changes in the fluorescence of the other ion. Sympathetic heating spectroscopy is a generalization of quantum logic spectroscopy, but does not require ions in the motional ground state or coherent control of the ion internal states. We have recently demonstrated this technique using two isotopes of Ca+ [Phys. Rev. A. 81, 043428 (2010)]. Limits of the method and potential applications for molecular spectroscopy are discussed.

Escalation of drug self-administration is a consequence of extended drug access and is thought to be specifically related to addiction, but few studies have investigated whether intake of non-drug reinforcers may also escalate with extended-access. The goal of these studies was to determine the effects of limited and extended-access to food reinforcers on behavioral and pharmacological endpoints in mice. In distinct groups, responding on a lever was maintained by liquid reinforcement, or nose-poke responses were maintained by sucrose pellets or liquid food in sessions lasting 1 h (limited-access) or 10 h (extended-access). The reinforcing strength of each food, as well as reinforcer-associated cues, was tested before and after extended-access using a progressive ratio (PR) schedule, and locomotor activity in response to novelty and increasing doses of cocaine was assessed in an open field setting in all animals after access to food reinforcers. Escalation of lever-pressing behavior reinforced by liquid food, but not nose-poke behavior reinforced by liquid food or sucrose pellets, was observed across successive extended-access sessions. A concomitant increase in the reinforcing strength of liquid food and its associated cues was apparent in mice that escalated their responding, but not in mice that did not escalate. Finally, extended reinforcer access leading to behavioral escalation was accompanied by an increased sensitivity to the psychostimulant effects of cocaine compared to limited-access. These findings indicate that behavioral escalation can develop as a consequence of extended-access to a non-drug reinforcer, although both the nature of the reinforcer (liquid versus solid food) and the topography of the operant response (lever versus nose-poke) modulate its development. These data also suggest that some of the behavioral and pharmacological corrolaries of behavioral escalation observed following extended-access to drug self-administration may not be due to drug exposure, but rather, may result from basic behavioral processes which underlie operant responding maintained by appetitive stimuli.

N,N-dipropyltryptamine (DPT) is a drug with hallucinogen-like effects belonging to the tryptamine superfamily of psychotomimetics. Numerous drugs belonging to this superfamily have been discovered or synthesized, and these compounds vary both in structure and in mechanism of action. In particular, their propensity to induce the release of or block the reuptake of monoamines varies with structure. To aid in the evaluation of the relationship between the structure of these compounds and their behavioral effects, mice were trained to discriminate DPT from saline. Dose dependent generalization of DPT in the presence and absence of the selective serotonin 5-HT1A antagonist WAY-100635 and the selective serotonin 5HT2A antagonist M100907 were evaluated. Furthermore, appropriate dosing of DPT was established by evaluating rate suppressant effects on a four component FR schedule of food reinforcement. Finally, the duration of action was evaluated by measuring the reestablishment of behavioral output across the same schedule when a single injection of DPT was administered prior to the session. Subsequent studies will evaluate the contribution of structure to the behavioral effects of the tryptamines by measuring the generalization of other members of this superfamily to the DPT cue. These studies supported by USPHS grants DA020645 and RR00165, and by the College on Problems of Drug Dependence.

Our laboratory has been investigating the role for the hypothalamo–pituitary–adrenal (HPA) axis and benzodiazepines in the behavioral effects of cocaine for several years now. The following represents our initial investigation of the influence of benzodiazepines on methamphetamine reward using conditioned place preference. In these experiments, methamphetamine (0.5 mg/kg ip) resulted in a robust conditioned place preference that was attenuated when the rats were pretreated with oxazepam (10 mg/kg ip) on the day of preference testing. These data suggest a potential role for benzodiazepines in the behavioral effects of methamphetamine. Additional research will be necessary to determine if the nature of these effects is similar with what has been observed with cocaine.