Electrical Engineering

We consider a two-species mixture of ultracold LiCs and LiRb molecules in the ground rotational state trapped on an optical lattice with one molecule per site. Rotational excitation of LiCs molecules gives rise to rotational excitons that undergo multiple collisions with LiRb molecules. This leads to localization of excitons. We present the results of numerical simulations demonstrating that the localization of excitons as well as interference patterns due to multiple scattering events can be controlled by applying an external electric field or varying the concentration and distribution of the LiRb molecules. The two-species mixture of polar molecules trapped on an optical lattice can thus be used as a quantum simulator of localization phenomena in disordered media. Our results show that the localization of excitons in the proposed system can be studied in real time.

We show that an ensemble of polar molecules trapped in an optical lattice can be considered as a controllable open quantum system. The coupling between collective rotational excitations and the motion of the molecules in the lattice potential can be controlled by varying the strength and orientation of an external DC electric field as well as the intensity of the trapping laser. The system can be described by a generalized Holstein Hamiltonian with tunable parameters and can be used as a quantum simulator of excitation energy transfer and polaron phenomena. We show that the character of excitation energy transfer can be modified by tuning experimental parameters.

We show that an ensemble of $^2\Sigma$ molecules in the rotationally ground state trapped on an optical lattice exhibits collective spin excitations that can be controlled by applying superimposed electric and magnetic fields. In particular, we show that the lowest energy excitation of the molecular ensemble at certain combinations of electric and magnetic fields leads to the formation of a magnetic Frenkel exciton. The exciton bandwidth can be tuned by varying the electric or magnetic fields. We show that the exciton states can be localized by creating vacancies in the optical lattice. The localization patterns of the magnetic exciton states are sensitive to the number and distribution of vacancies, which can be exploited for engineering many-body entangled spin states. We consider the dynamics of magnetic exciton wavepackets and show that the spin excitation transfer between molecules in an optical lattice can be accelerated or slowed down by tuning an external magnetic or electric field.

We show that an ensemble of polar molecules trapped in an optical lattice can be considered as a controllable open quantum system. The coupling between collective rotational excitations and the motion of the molecules in the lattice potential can be controlled by varying the strength and orientation of an external DC electric field as well as the intensity of the trapping laser. The system can be described by a generalized Holstein Hamiltonian with tunable parameters and can be used as a quantum simulator of excitation energy transfer and polaron phenomena. We show that the character of excitation energy transfer can be modified by tuning experimental parameters.

In the present work, we demonstrate the possibility of controlling by an external field the dynamics of collective excitations (excitons) of molecules on an optical lattice. We show that a suitably chosen two-species mixture of ultracold polar molecules loaded on an optical lattice forms a phononless crystal, where exciton-impurity interactions can be controlled by applying an external electric field. This can be used for the controlled creation of many-body entangled states of ultracold molecules and the time-domain quantum simulation of disorder-induced localization and delocalization of quantum particles.

We consider ultracold polar molecules in the ro-vibrational ground state trapped on an optical lattice with one molecule per lattice site. Rotational excitation of molecules produces rotational excitons that can propagate throughout the optical lattice due to long-range dipole-dipole interaction between molecules. Unlike excitons in most naturally occurring solids, these rotational excitons have a negative effective mass. Molecular impurities introduced into the lattice break the translational symmetry and scatter excitons. We show that the exciton-impurity interaction strength can be tuned by an external electric field, leading to exciton-impurity scattering resonances. This can be used to realize different kinetic regimes of exciton dynamics, from free propagation to Anderson localization. The negative effective mass of the excitons results in resonant scattering produced by repulsive, and not attractive, scattering potentials.

... The user can use the lens to “peel away” layers of the earth, asshown in figure 7. The Worlds In Miniature (WIM): Previous work in virtual environments that we can also think of as a 3D volumetric lens is the Worlds In Miniature (WIM)[ 16], shown in figure 8. The WIM is an ...

In this paper we describe the development of rules to drive a quasi-articulatory speech synthesizer, HLsyn. HLsyn has 13 parameters, which are mapped to the parameters of a formant synthesizer. Its small number of parameters combined with the computational simplicity of a formant synthesizer make it a good basis for a text-to-speech system. An overview of the rule-driven system, called

The aim of the research reported in this paper is to formulate a set of acoustic parameters of the voicing source that reflect individual differences in the voice qualities of female speakers. Theoretical analysis and observations of experimental data suggest that a more open glottal configuration results in a glottal volume-velocity waveform with relatively greater low-frequency and weaker high-frequency components, compared to a waveform produced with a more adducted glottal configuration. The more open glottal configuration also leads to a greater source of aspiration noise and larger bandwidths of the natural frequencies of the vocal tract, particularly the first formant. These different attributes of the glottal waveform can be measured directly from the speech spectrum or waveform. A set of acoustic parameters that are likely to indicate glottal characteristics is described. These parameters are measured in the speech of a group of female speakers, and the glottal configurations of the speakers are hypothesized. This research contributes to the description of normal variations of voicing characteristics across speakers and to a continuing effort to improve the analysis and synthesis of female speech. It may also have applications in clinical settings.

The current work is part of a project to character- ize the subglottal pressure (Ps) contour associated with a spoken utterance in terms of the distribution of pitch accents and of phrase and boundary tones. It is found that the nuclear pitch accent does not define the start of the termination phase; the utterance off- set is a better marker.

The current work is part of a project to character- ize the subglottal pressure (Ps) contour associated with a spoken utterance in terms of the distribution of pitch accents and of phrase and boundary tones. It is found that the nuclear pitch accent does not define the start of the termination phase; the utterance off- set is a better marker.