Batsheva de Rothschild Seminar & ISF - Israel Science Foundation workshop on Light-matter Interaction: Focus on Novel Observable nonHermitian Phenomena Kibbutz Ein-Gedi April 21st-26th, 2013 Sponsors: The Israel Academy of Sciences & Humanities - The Batsheva de Rothschild Fund Israel Science Foundation Technion institute of advanced studies in theoretical chemistry Organizers: Nimrod Moiseyev (Technion) Moti Segev (Technion) Yaron Silberberg (Weizmann) Doron Cohen (Ben-Gurion) Coordinators: Gila Gutman- reservation, accommodation and transportation correspondence Abstracts Sunday 21/4/2103 16:15-18:30 Motivation for using non-Hermitian formalism Michael Berry, H H Wills Physics Laboratory, University of Bristol, UK NH: PT’s big brother Hermitian (H) and PT symmetric hamiltonians are overlapping subsets of the class of all (mostly nonhermitian - NH) operators governing physical evolution. Recent claims that PT is physically more fundamental than H are critically examined. The interesting behaviour of nonhermitian PT symmetric operators is associated with degeneracies, and is not characteristic of PT but rather is a property of the wider class of all NH operators, understood in light and atom optics for many years. Avraham Nitzan, Tel-Aviv University Non-Hermitian quantum mechanics in molecular transport problems Molecular transport problems, by definition, involve open quantum systems, where description by nonhermitian Hamiltonians evolve naturally from the need to describe such processes within a finite computational framework. The derivation of the golden rule from steady state quantum mechanics provides the simplest example. The use of absorbing boundary conditions in scattering computations is another conceptually simple example that serves to illustrate the possibility to choose between phenomenological absorbing boundary conditions and exact calculation of the system's self energy. More general situations that lead to stochastic dynamics will be also discussed and the difference between population and phase relaxation will be emphasized. Finally, modifications of the system Hamiltonian that reflect measurement processes will be illustrated. Lenz Cederbaum, Heidelberg University ICD and Dynamic Interference in Free Electron Lasers by non-Hermitian Quantum Mechanics Monday 22/4/2103 8:45-10:45 Non-Hermitian degeneracy (Exceptional points) Raam Uzdin , The Hebrew University of Jerusalem Time dependent non-unitary systems and non-Hermitian resources After briefly exploring a few effects unique to non-Hermitian time-dependent Hamiltonians, we will show that the energy difference of the instantaneous Hamiltonian does not completely capture the Hamiltonian capability to change states. This is related to the fact that non-Hermitian degeneracies have another energy scale which does not appear in the Hermitian case. We will present an alternative formalism and then quantify the minimal resources needed for "magic" non unitary operations such as "faster than Hermitian" motion, and perfect state discrimination of non-orthogonal states. Eva-Maria Graefe, Imperial College Signatures of three coalescing eigenfunctions Parameter dependent non-Hermitian quantum systems typically not only possess eigenvalue degeneracies, but also degeneracies of the corresponding eigenfunctions at exceptional points. Here we present a characterisation of behaviours of symmetric Hamiltonians with three coalescing eigenfunctions, using perturbation theory for non-Hermitian operators. Two main types of parameter perturbations need to be distinguished, which lead to characteristic eigenvalue and eigenvector patterns under cyclic variation. A physical system is introduced for which both behaviours might be experimentally accessible. Uwe Guenther ,Helmholtz center Dresden Nonlinear PT-symmetric plaquettes Nonlinear coupled gain-loss oscillator oligomers (plaquettes) of 4-node and 5-node type in a 2D-plane are studied. Their specific PT-symmetry properties are investigated, the occurrence of exceptional points (up to third-order) as well as their various nonlinear dynamical regimes. collaboration with: Kai Li, Panayotis Kevrekidis and Boris Malomed paper: J Phys A 45 (2012) 444021 11:15-12:50 Realization of exceptional points Achim Richter , Technische Universität Darmstadt, Germany Exceptional Points in Microwave Billiards with and without Time Reversal Symmetry * After a brief introduction into generic features of microwave resonators as quantum billiards and open scattering systems it is discussed how eigenvalues, eigenfunctions and eigenvectors of a dissipative time reversal invariant and non-invariant system, respectively, close to and at an exceptional point (EP) are determined experimentally [1,2]. The full EP-Hamiltonian can be extracted from the measured scattering matrix. While the EP is encircled the eigenvectors gather geometric phases and in addition amplitudes different from unity. Finally, the presence of parity-time (PT) symmetry for the non-Hermitian two-state Hamiltonian in the vicinity of the EP is shown. * Work supported within the SFB634 by the Deutsche Forschungsgemeinschaft [1] C. Dembowski, H.-D. Gräf, H.L. Harney, A. Heine, W.D. Heiss, H. Rehfeld, and A. Richter, Phys. Rev. Lett. 86, 787 (2001) [2] B. Dietz, H. L. Harney, O.N. Kirillov, M. Miski-Oglu, A. Richter, and Florian Schäfer, Phys. Rev. Lett. 106, 150403 (2011) [3] S. Bittner, B. Dietz, U. Günther, H.L. Harney, M. Miski-Oglu, A. Richter, and F. Schäfer, Phys. Rev. Lett. 108, 024101 (2012) Demetrios Christodoulidies ,University of Central Florida Non-Hermitian and PT-symmetric Optical Systems 17:00-18:20 Realization of exceptional points Holger Cartarius, Stuttgart University Exceptional points and PT symmetry in Bose-Einstein condensates Work done together with: D. Dast, R. Eichler, D. Haag, W. D. Heiss, M. Kreibich, J. Main, G. Wunner In Bose-Einstein condensates exceptional points appear in various cases. They are, e.g. connected with stability thresholds of the s-wave scattering length below which a collapse of the condensate sets in. Recently it has been shown that exceptional points also appear for Bose-Einstein condensates in an external PTsymmetric potential. To study the effects of PT symmetry in Bose-Einstein condensates we follow a proposal by Klaiman et al. of a Bose-Einstein condensate in a double-well setup. Particles removed from one well and coherently injected into the other can be described by an imaginary gain-loss parameter rendering the external potential complex PT symmetric. It has been shown that PT-symmetric wave functions exist and thus the PT symmetry is not destroyed by the nonlinearity of the Gross-Pitaevskii equation. In agreement with their counterparts in linear quantum mechanics they merge in a second-order exceptional point (EP2). A crucial difference is the bifurcation of PT-broken states from one of the PT-symmetric eigenstates for gain-loss parameters far below the EP2. The new bifurcation point turns out to be a third-order exceptional point (EP3). We investigate the exceptional points appearing in Bose-Einstein condensates and describe their physical consequences, i.e. PT symmetry breaking and an important influence on the dynamics of the condensate's wave function. Suggestions for experimental realizations are presented. Stefan Rotter ,Vienna University, Institute for Theoretical Physics Pump-Controlled Exceptional Points and Random Laser Emission I will show that the above-threshold behavior of a laser can be strongly affected by exceptional points which are induced by pumping the laser non-uniformly [1]. In the vicinity of these points the laser may turn off even when the overall pump power deposited in the system is increased. In extension of this work, we could recently demonstrate that suitably optimized pump profiles allow us to control the angular emission pattern of a random laser such as to achieve highly directional emission or any other desired pattern [2]. [1] Liertzer, Ge, Cerjan, Stone, Tureci, and Rotter, Phys. Rev. Lett. 108, 173901 (2012). [2] Hisch, Liertzer, Pogany, Mintert, Rotter (to be submitted) 19:30-20:50 Dynamical control by external fields Daniel Strasser ,The Hebrew University of Jerusalem Multiple detachment of SF6- molecular ions by shaped intense laser pulses Since the development of intense femtosecond laser technologies, significant effort was made towards understanding of the basic interaction of such intense laser pulses with matter. In particular, the study of multiple ionization of neutral atoms and high order harmonic generation led to the development of a simplified semi-classical understanding of these highly non-perturbative mechanisms, commonly known as the “three step model”. Furthermore, this basic understanding enabled the technological breakthroughs that allow generating record breaking attosecond pulses, and to perform time resolved experiments on the attoscond timescale. In my presentation I will discuss our recent experimental work, using fast beam photofragment spectroscopy to explore the interaction of shaped intense laser pulses with the SF6- negatively charged molecular ion. Peter Schmelcher, Centre for Optical Quantum Technologies, Luruper Chaussee 149, 22761 Hamburg, and Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany Ultralong-range molecules in external fields We explore the possibility to shape and control the properties and behaviour of ultralong-range molecules with external electric or electric and magnetic fields. The interaction of the neutral ground state atom with the highly excited Rydberg electron is described via a Fermi-pseudopotential approximation, including s-wave and p-wave contributions. Using a non-relativistic pseudopotential for the binding of the electron to the ionic core, which properly describes the quantum defects of the scattering of the electron off the core, a basis is obtained within which the combined molecular Rydberg-perturber Hamiltonian in the presence of the external fields is diagonalized. As a result the adiabatic Born-Oppenheimer potential energy surfaces, which determine the molecular configurations and dynamics, are obtained. Varying the electric field strength the oscillating energy surfaces possessing many well-separated and pronounced local potential wells, can be shifted with respect to each other. In particular, it is possible to avoid the intersection of p-wave dominated states with swave dominated ones, which is ubiquitous in the absence of fields, close to the equilibrium vibrational ground states. This leads to an enhanced stability of the ultralong-range molecular states. The corresponding vibrational dynamics is analyzed. Finally, we present a preparation scheme for high-l molecular electronic states via a two photon excitation process. In a second step, we show the existence of ultra-long-range giant dipole molecules in crossed electric and magnetic fields formed by a neutral alkali ground state atom that is bound to the decentered electronic wave function of a giant dipole atom. Giant dipole atoms in crossed fields are of peculiar shape: their highly excited electronic wave function is due to the combined. action of electric and magnetic fields strongly decentered and localized completely off the ionic core. The neutral ground state atom is bound to this isolated Rydberg cloud and, opposite to the standard e.g. trilobite molecules, does not possess any radiative decay channel. The resulting molecules are truly giant with internuclear distances up to several $\mu m$. We analyze the resulting three-dimensional adiabatic potential energy surfaces depending on the degree of electronic excitation: Disturbed torus-like multi-well structure are observed for excited states which can, due to avoided crossings, show an increasing topological complexity. Binding energies and the vibrational motion in the energetically lowest surfaces are analyzed by means of perturbation theory and exact diagonalization techniques. Finally, we demonstrate the existence of intersection manifolds of excited electronic states that potentially lead to an 'ultrafast' vibrational decay of the ground state atom dynamics. Tuesday 23/4/2103 8:30-10:45 Non Hermitian optics A. Douglas Stone , Dept. of Applied Physics – Yale University For Light-Matter Interactions: Focus on Novel Observable Non-Hermitian Phenomena Lasers and Anti-lasers: Non-Hermitian to the Max Amplifiers and attenuators in optics are prototype non-hermitian systems described by non-energy conserving electromagnetic wave equations. A laser at threshold is the extreme case where the amplification goes to infinity, the system starts to self-oscillate, and the non-linearity of the gain medium is required to stabilize the steady-state. Recently we have developed, and will review here, Steady-state Ab initio Laser Theory (SALT), which calculates directly all of the lasing properties in the non-linear multimode steady-state, treating the nonhermiticity exactly, for complex laser cavities and pumping schemes. SALT emphasizes that a laser is a certain kind of non-hermitian scattering system, and the laser threshold corresponds to a pole of the S-matrix on the real axis. Applying time-reversal to the threshold laser equation maps it to an S-matrix with a zero on the real axis, describing a coherent perfect absorber (CPA), a lossy cavity which perfectly absorbs the timereverse of the lasing mode in steady state. Finally, a cavity with parity-time symmetry, and sufficient gain/loss, can function simultaneously as a CPA and laser, with a pole and zero coincident on the real axis. More generally, cavities with non-uniform gain or loss are described by non-hermitian equations, which have exceptional points that determine the motion of poles and zeros, and lead to novel, observable optical phenomena involving lasing and perfect absorption. Tsampikos Kottos, Wesleyan University Taming wave propagation via Parity-Time symmetry Using integrated photonics and electronics as a play-fields we show how one can construct new circuitry designs that allow for asymmetric wave transport by making use of novel properties emerging from PTsymmetries. Jan Wiersig , University of Magdeburg Non-Hermitian phenomena in passive optical microcavities Optical microcavities are inherently open systems due to leakage of light through the cavity’s boundary. In the past such systems have been successfully described by non-Hermitian effective Hamiltonians . In this talk, two interesting phenomena based on the non-Herminicity are discussed. The first one can be observed when two microdisk cavities are coupled to form a photonic molecule. Experimental and numerical data is presented which demonstrates that near an avoided resonance crossing the quality factor of one mode can significantly increase above the non-resonant values of both modes. The second phenomenon shows up in deformed or otherwise slightly perturbed microdisks which do not possess any mirror symmetry. A theoretical analysis and numerical simulations show that the long-lived modes in such cavities come in highly non-orthogonal pairs of modes. Within each pair a propagation direction (clockwise or counterclockwise) dominates. The physical origin of this ‘chirality’ is asymmetric backscattering of clockwise and counterclockwise propagating waves. This phenomenon is linked to the presence of non-Hermitian degeneracies. Finally, such asymmetric cavities are coupled to form optical waveguides with unusual dispersion properties. 11:15-12:35 Non Hermitian optics (cont.) Hui Cao ,Yale University Time-Reversed Lasing and Interferometric Control of Absorption Optical absorption is usually considered deleterious, something to avoid if at all possible. We show that a perfect absorption not only leads to complete coupling of light into plasmonic nanostructures, but also produces subwavelength focusing by suppressing diffraction. Based on the time-reversed process of lasing action, we propose and demonstrate an interferometric control of coherent light absorption. Mikael Rechtsman,Technion Photonic Topological Insulators 16:00-18:00 Non Hermitian optics (cont.) Barbara Dietz ,TU Darmstadt Bound States in Bent Waveguides: Analytical and Experimental Approach Bound states in quantum wires or open electromagnetic waveguides with curves, bends or bulges have received much interest since their existence is a purely wave-dynamical phenomenon which has no classical analogue. We present microwave experiments with sharply bent waveguides may have arbitrarily many bound states depending on the angle of the bend: new bound states emerge at certain critical angles. Several waveguides with bending angles close to these critical ones were investigated. In particular, we studied the features of the transition from bound to unbound states caused by the variation of the bending angle. Furthermore, the effect of the finite length of the waveguide was investigated. With the help of an effective potential approach we computed the bound states and the critical bending angles [1]. The analytical results were confirmed by numerical calculations as well as experimental measurements of the spectra and electric field intensity distributions of electromagnetic waveguides. The work was supported by the DFG within SFB 634. [1] S. Bittner, B. Dietz, M. Miski-Oglu, A. Richter, C. Ripp, E. Sadurní, and W. P. Schleich, Phys. Rev. E, in press Konstantinos G. Makris, Department of Electrical Engineering, Princeton University Wave propagation in PT-symmetric optical potentials The first experimental observation of parity-time (PT) symmetry breaking in any physical system was recently demonstrated. In this context of PT-symmetric Optics, we examine the characteristics of multimode PTsymmetric potentials. The existence of many spatial supermodes leads to multiple spectral phase transitions, and vortex optical currents in the transverse poynting vector. Resent results regarding diffraction dynamics close to the exceptional points of PT lattices, negative refraction effects, as well as, scattering in PT optical cavities will also be presented. Li Ge, Princeton University Antisymmetric PT-photonic structures with balanced positive and negative index materials In this talk I will discuss a new class of synthetic optical materials in which the refractive index satisfies n(-x)=-n*(x). We term such systems antisymmetric parity-time (APT) structures. Unlike PT- symmetric systems which require balanced gain and loss, i.e. n(-x)=n*(x), APT systems consist of balanced positive and negative index materials. Despite the seemingly PT-symmetric optical potential V(x)=n(x)^2\omega^2/c^2, APT systems are not invariant under combined PT operations due to the discontinuity of the spatial derivative of the wavefunction. We show that APT systems can display intriguing properties such as spontaneous phase transition of the scattering matrix, bidirectional invisibility, and a continuous lasing spectrum. Wednesday 24/4/2103 8:30-10:45 Strong Laser Physics Nirit Dudovich , Weizmann Institute of Science When does an electron exit a tunneling barrier? Tunneling of a particle through a barrier is one of the most fundamental and ubiquitous quantum processes. When induced by an intense laser field, electron tunneling from atoms and molecules initiates a broad range of processes that evolve on the attosecond time-scale1,2. As the liberated electron is driven by the laser field, it can return to the parent ion and recombine to the initial (ground) state, releasing its energy in an attosecond burst of light. This process, known as High Harmonic Generation (HHG) provides an excellent spatiotemporal filter for the electron motion. The angstrom-scale spatial resolution is determined by the size of the atomic ground state to which the electron must recombine. The attosecond temporal resolution arises from the mapping between the photon energy (harmonic order) and the return time of the corresponding electron trajectory. In the talk I will describe how by adding a weak perturbation allows us to probe both the ionization times and the recollision times in simple atomic systems3. Our results which deviate from the simple classical model are in good agreement with the quantum path analysis. Next, I will describe how a similar approach enables us to measure the instantaneous tunneling probability within the optical cycle. Finally, I will discuss the probing of molecular systems where more than one ionization channel participates the process4,5. As an example I will show how multiple channel ionization is probed in aligned CO2 molecules. I will describe how the high sensitivity of the measurement allows us to probe subtle differences between two ionization channels 3. This experiment provides an additional, important step towards the ability to resolve multielectron phenomena -- a long term goal of attosecond studies. 1. 2. 3. 4. Keldysh, L. V. Ionization in the field of a strong electromagnetic wave. Sov. Phys. JETP 20, 1307–1314 (1965) P. B. Corkum and F. Krausz, Attosecond science, Nature Physics 3, 381 (2007). D. Shafir et al., “Resolving the time when an electron exits a tunneling barrier, Nature 485, 343 (2012). B. K. McFarland, J. P. Farrell, P. H. Bucksbaum and M. Gühr, High Harmonic Generation from Multiple Orbitals in N2, Science 322, 1232-1235 (2008). 5. Olga Smirnova et al., High harmonic interferometry of multi-electron dynamics in molecules. Nature 460, 972-977 (2009). Oren Cohen, Technion Generation of high-order harmonics with controlled polarization: from linear through elliptic to circular polarization We demonstrate, theoretically and experimentally, that the polarization of high-order harmonics driven by counter-rotating elliptically-polarized bichromatic pulse are fully controllable: from linear through elliptic to circular polarization. We also observe new selection rules. Barak Dayan , Weizmann Institute of Science 11:15-13:15 Strong Laser Physics (cont.) Avner Fleischer , Technion Where does a photo-electron appear in the continuum ? In tunnel ionization of atoms by strong laser fields it is known that the electron appears in the continuum at the outer turning point of the tunnel barrier. It is reasonable to assume that a reduction in the number of photons which participate in the ionization will shift the appearance location of the ionized electron towards the origin. Here we verify this assumption and suggest a measurement that could reveal where an electron appears in the continuum. As a result of interferences between the electronic wavelets which are released into the continuum, the photoionization rate of atoms is modified by the presence of a weak dc field in an oscillatory manner. By measuring the phase of the oscillations, the average appearance position of the photoionized electron in the continuum can be retrieved Vitali Averbukh, Imperial College New ideas for attosecond time-resolved spectroscopies of electron hole dynamics In this talk I will present two of our recent ideas for new attosecond time-resolved measurements of electron hole dynamics: * Single-photon laser enabled Auger spectroscopy * High-harmonic generation spectroscopy of Auger-type transitions Unlike attosecond streaking, the proposed spectroscopies do not rely on photo- or secondary electron emission and are applicable to ultrafast electronic processes involving bound-bound transitions, such as electron correlation-driven charge migration. We simulate the new attosecond spectroscopies using both model and ab initio methods. Specific applications include hole migration in glycine, atomic Auger and Coster-Kronig decays as well as quasi-exponential dynamics of molecular orbital breakdown in trans-butadiene. Alexandra Landsman ,Princeton 16:00-18:00 Strong Laser Physics (cont.) Zohar Amitay ,Technion Coherence Generation and Control in the Free-to-Bound Binary Reaction of Hot Atom-Atom Photoassociation A long-standing yet unrealized dream since the early days of coherent control is coherent control of general photo-induced bimolecular chemical reactions. Realizing this dream will create a new type of photochemistry that coherently photo-induces new chemical reactions and selectively controls the yields and branching ratios in existing and new photo-reactions. As significant steps along this direction, we present here experimental and theoretical control results for the free-to-bound binary reaction of multiphoton femtosecond photoassociation of thermally hot atoms (hot fsPA). In this process, a (shaped) femtosecond pulse induces a chemical bond formation between the colliding hot atoms via a free-to-bound multiphoton transition, and generates a bound excited diatomic molecule. Coherent control of hot fs-PA is, on one hand, an important model for femtosecond control of simple binary photo-reactions and, on the other hand, an essential prerequisite for femtosecond control of more complicated binary reactions using extended multi-pulse schemes that employ the fs-PA as a first step. Our results are presented for fs-PA of hot magnesium atoms into bound magnesium dimer molecules, i.e., Mg+MgMg2*, with the thermal ensemble of Mg atoms held at a temperature of 1000 K. The process is induced by intense (shaped) femtosecond pulses (70-fs transform-limited duration; 840-nm central wavelength) in the strong-field regime. The experimental results, accompanied by a comprehensive theoretical model and calculations, include the first-time demonstration and observation of the following: (i) The formation of diatomic molecules with vibrational and rotational coherence in the process of photoassociation. This corresponds to the generation of the photo-associated molecules in a coherent superposition of rovibrational states. Generating vibrational coherence is essential in order to utilize hot fs-PA as a basis for chemical reaction coherent control, since the vibrational degrees of freedom determine the fate of bond making and breaking. (ii) Inducing the fs-PA process via multiphoton excitations. This significantly extends the variety of molecular species and reactions that are candidates for chemical reaction control. (iii) Femtosecond coherent control of the photoassociation process. In the first part, the multiphoton photoassociation probability (yield) is coherently controlled by linearly-chirped shaped pulses, and a very strong enhancement is achieved with a proper positive chirp. Then, PA yield control that involves also intermediate field-free coherent rovibrational dynamics is demonstrated using shaped pulses with triangular spectral phase patterns (in the shape of V or). Pananghat Balanarayan, Technion High-frequency strong laser physics and chemistry: Linear Stark effect for atoms and strong chemical bond in rare-gas dimer Current trends in laser technology have reached the regime of studying atoms stabilized against ionization, going beyond the perturbation theory. In this work, properties of a laser-dressed sulfur atom are examined in this stabilization regime. The electronic structure of a sulfur atom changes dramatically as it interacts with strong high frequency laser fields. Degenerate molecular-like states are obtained for the ground state triplet of the laser-dressed sulfur atom for high-frequency and moderate intensity laser parameters. The degenerate ground state is obtained for a laser intensity which is smaller by more than one order of magnitude than the intensity required for hydrogen atoms due to many electron screening effects. An infinitesimally weak static field mixes these degenerate states to give rise to asymmetric states with large permanent dipole moments. Hence, a strong linear Stark effect rather than the usual quadratic one is obtained. The van der Waals complex of the helium dimer has a very small binding energy and a bond distance of 52 Angstrom. The free field potential has been found to support a single vibrational bound state, that has been detected in diffraction grating experiments. With a high intensity and high frequency laser, stable helium dimer molecules with a binding energy of 12.5 eV, which are much stronger than conventional molecular hydrogen bonds, are produced. The bond distance of the dimer produced by the strong laser field is equal to 2.01 Angstroms. All these effects are seen in the high frequency high intensity regime of the laser within the zeroth order Kramer-Henneberger states of the laser dressed atoms and molecules. Ido Gilary, Technion Time asymmetric state exchange mechanism 19:30:21:20 Dynamical control in optical lattices Immanuel Bloch ,Max Planck Institute for quantum optics From Rydberg Crystals to Bound Magnons - Probing the Non-Equilibrium Dynamics of Ultracold Atoms in Optical Lattices Ultracold atoms in optical lattice form an ideal testbed to probe the non-equilibrium dynamics of quantum many-body systems. In particular recent high-resolution imaging and control techniques allow to probe dynamically evolving non-local correlations in an unprecedented way. As an example, I will focus in my talk on the dynamical excitation of spatially ordered Rydberg structures that are formed through laser exctiation from ground state Mott insulating atoms. In addition, I will show how single-spin and spin-pair impuritites can be used to directly reveal polaron dynamics in a strongy interacting superfluid or the bound state of two magnons in a quantum ferromagnet. New atom interferometric schemes to directly probe the Green's function of a many-body system through the impurity dynamics will be discussed. Hossein Sadeghpour, ITAMP, Harvard Anomalous heating noise in ion traps: what is it and can it be mitigated? Thursday 25/4/2103 8:30-10:30 Dynamical control by external fields (cont.) Uri Peskin, Technion Coherently controlled conductance in single molecule junctions Molecular junctions, in which a single molecule is coupled to two macroscopic electrodes, provide a unique scenario to study charge and energy transport through molecular systems in both equilibrium and nonequilibrium conditions. In the talk, we shall discuss new possibilities for utilizing the unique transport properties of molecular junctions for electronic and energy-conversion devices. Having a molecule as the ‘bottle neck’, the characteristic length and time scales imply that coherent (phase conserving) transport dominates the transport properties, and suggests that these systems can be coherently controlled. In particular we shall focus on a molecular coherent ‘electron pump’ which converts radiation field into directed electronic current. The principle of operation will be analyzed theoretically under conditions ranging from a sudden pulse to cw excitation, and the principles of coherent control by the radiation field in the presence of decoherence by the leads will be outlined. Finally, we shall propose an experimental design for measuring field induced dynamics in molecular junctions (with sub pico-second resolution) using steady state current measurements Johannes Feist , University Autónoma de Madrid, Spain Condensation of ultralight particles: towards a quantum degenerate gas of plexcitons Condensation of bosons, where a single quantum state is macroscopically populated, is a fascinating phenomenon spanning diverse areas of physics. It lies at the heart of superfluidity and superconductivity, as well as the Bose-Einstein condensation of ultracold dilute atoms, which was achieved close to twenty years ago. An important goal is to find systems in which condensation takes place at higher temperatures, even at or above room temperature. Bosonic quasi-particles in solids are excellent candidates due to their light effective masses, and signatures of condensation have been observed for semiconductor excitons and exciton-polaritons at temperatures of a few K, as well as for magnons and cavity photons at room temperature. I will present and discuss experimental signatures of quantum condensation of plexcitons at room temperature. Plexcitons are bosonic quasiparticles formed by strong coupling between organic molecule excitons and surface plasmon polaritons (quasi-bound modes confined on a subwavelength scale at metaldielectric interfaces). Our system consists of a periodic array of metallic nanorods covered by a polymer layer doped with an organic dye. By increasing the plexciton density through optical pumping, we observe signatures of thermalization and condensation, such as the emergence of Bogoliubov-Goldstone modes, despite the nonequilibrium character of this driven and dissipative system. Ed Narevicius, Weizmann Institute of Science Chemistry of the Quantum Kind There has been a long-standing quest to observe chemical reactions at low temperatures where reaction rates and pathways are governed by quantum mechanical effects. So far this field of Quantum Chemistry has been dominated by theory. The difficulty has been to realize in the laboratory low enough collisional velocities between neutral reactants, so that the quantum wave nature could be observed. We will discuss our merged neutral supersonic beams method that enabled the observation of clear quantum effects in low temperature reactions. We observed orbiting resonances in the Penning ionization reaction of argon and molecular hydrogen with metastable helium leading to a sharp increase in the absolute reaction rate in the energy range corresponding to a few degrees kelvin down to 10 mK. Our method is widely applicable to many canonical chemical reactions, and will enable experimental studies of Quantum Chemistry. 11:00-13:15 Quantum chaos and complexity in decay, emission, and relaxation processes Patrick Sebbah ,Langevin Institute Emission control of a random laser : Turning a random laser into a tunable singlemode laser by active pump shaping We present an innovative mirrorless optofluidic random laser where the optical cavity has been replaced by a random scattering structure. We achieve emission control at any desired wavelength by iteratively shaping the optical pump profile. This method is proposed to explore pump-induced exceptional points in lasers. Ulrich Kuhl , Marburg University Experimental realization of Resonant assisted tunneling in open systems In quantum mechanical billards with a mixed phase space direct tunneling from regular islands to the chaotic sea is well known [1],[2]. For quantum mechanical maps it was shown, that the tunneling rates are determined by another effect the so-called resonance-assisted tunneling [3], which is an indirect process whire another stable island. To verify this theory a Cosin-shaped microwave resonator with absorbers was designed, where the absorbers are located in such a way that the chaotic sea is replaced by the continuum. The experimental results are in good agreement with the theoretical predictions Ofir Alon ,Haifa University Many body decay by tunneling and wave chaos in BEC 17:00-18:20 Novel phenomena in control of light matter interactions David Tannor, Weizmann Institute of Science Phase Space Approach to Quantum Mechanical Calculations for Large Systems: Application to Attosecond Electron Dynamics We present a method for solving both the time-independent and time-dependent Schrödinger equations based on the von Neumann (vN) lattice of phase space Gaussians. By incorporating periodic boundary conditions into the vN lattice we solve a longstanding problem of convergence of the vN method. This opens the door to tailoring quantum calculations to the underlying classical phase space structure while retaining the accuracy of the Fourier grid basis. In the classical limit the method reaches the remarkable efficiency of 1 basis function per 1 eigenstate. The method can be combined with a wavelet-like scaling of the basis functions, which is particularly useful for Coulombic potentials. We illustrate the method by calculating the vibrational dynamics of polyatomic systems as well as simulating attosecond electron dynamics in the presence of combined strong XUV and NIR laser fields . .1A. Shimshovitz and D. J. Tannor, Phase Space Approach to Solving the Time-independent Schrödinger Equation, Phys. Rev. Lett. 109, 070402 (2012.) .2N. Takemoto, A. Shimshovitz and D. J. Tannor, Phase Space Approach to Solving the Time-dependent Schrödinger Equation: Application to the Simulation and Control of Attosecond Electron Dynamics in the Presence of a Strong Laser Field, J. Chem. Phys. 137, 011102 (2012) (Communication.) 3. A. Shimshovitz and D. J. Tannor, Phase Space Wavelets for Solving Coulomb Problems, J. Chem. Phys. 137, 101103 (2012) (Communication). Sandy Ruhman, The Hebrew University of Jerusalem Time asymmetric dynamics in biological systems

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