AtMol Research Seminars
Seminar Archive
Seminars Next Term

Unless otherwise advertised, all talks are in room Ph30 at 4:15pm on Wednesdays.

Please provide Anna Marchant ( ) with title and abstract details.

Next Seminar

Date Speaker Institution
  A Rydberg Quantum Simulator
17th March Mr. Hendrik Weimer University of Stuttgart

A universal quantum simulator is a controlled quantum device which efficiently reproduces the dynamics of any other many particle quantum system with short range interactions. Based on a recent proposal for a many-body gate using strong interactions between Rydberg atoms [1], we present an implementation of a digital quantum simulator in an optical lattice with large lattice spacing [2]. Special focus is on the efficient simulation of Hamiltonians with local many-body interactions, including exotic spin models such as Kitaev's toric code, string nets, and lattice gauge theories. In addition, we show that the formalism also provides the simulation of dissipative terms taking the Lindblad form with many-body jump operators. These dissipative terms allow for the efficient ground state cooling and state preparation.

[1] M. Müller, I. Lesanovsky, H. Weimer, H. P. Büchler, P. Zoller, Phys. Rev. Lett. 102, 170502 (2009).
[2] H. Weimer, M. Müller, I. Lesanovsky, P. Zoller, H. P. Büchler, Nature Phys. (accepted), arXiv:0907.1657

Epiphany 2010

Date Speaker Institution
Light propagation in ultracold atomic gases
20th January Dr Francesco Bariani University of Trento

Laser light is a fundamental tool to manipulate ultracold atoms and it is used to engineer different atomic systems whose optical responses show peculiar features. Atomic clouds are then of great interest as novel optical media. For example, it is possible to obtain a higly dispersive behavior in the resonat regions of the spectrum. Furthermore the coherent dressing of atomic excitations by means of an external field, which leads to the well-known Electromagnetically Induced Transparency, allows for an efficient propagation of light through the system in combination with the possibility of a dynamic modulation of the dielectric properties. In the first part of the talk, I will describe a simple model for the optical response of a Mott-insulator composed by 2-level atoms: The interplay of the resonant behavior of atoms and the periodicity of the system can be detected in the reflectivity spectrum. In the second part of the talk, I will present a new scheme for wave-packet manipulation based on a multilayer structure made of clouds of 3-level atoms under EIT conditions separated by vacuum regions.

Novel Many-Body Phenomena in Ultracold Dipolar Gases
27th January Dr Shai Ronen University of Innsbruck

Ultracold dipolar gases of atoms and molecules promise new directions and exciting applications for novel quantum phase transitions, precision measurement, quantum information science, and chemical reactions at ultra cold energies. In this talk I will describe our work on the many body properties of dipolar Bose-Einstein condensates and degenerate Fermi gases. I will show how the long range and non-istoropic dipole-dipole interactions give rise to novel effects such as new structure of the ground state, roton feature in the excitation spectrum, local instabilities, spontaneous dynamical breaking of symmetry, and non isotropic speed of sound, with intimate relation to phenomena in superfluid He-4 and He-3.

Matter wave interference of large molecules
3rd February Dr Hendrik Ulbricht University of Southampton

We will report on recent progress in molecule interferometry. The basic motivation for coherent manipulation of such large particles is to explore fundamental limits of physical concepts as quantum mechanics. But also to investigate the possibility to use such techniques for applications as molecule metrology1, 2, molecule sorting by interferometric beam deflection3, 4, diffractive surface deposition for molecular lithography in the realm of emerging nanotechnologies. The central molecule beam manipulation device is a three-grating Talbot-Lau interferometer, which was realized in different versions. For inststance by making use of three material gratings5 or by mixing light gratings with material ones in the so-called Kapitza-Dirac Talbot-Lau interferometer (KDTLI)6, 7. The coherent handling or manipulation of molecules in the mass regime of serveral 1000 amu (atomic mass units) is still challenging as all different kinds of beam generation, cooling and slowing as well as detection techniques has to be developed.

Therefore we will here report on two novel techniques for neutral molecule detection and interferometric surface deposition, which are the single molecule detection by superconducting NbN single-photon detectors8 and ultra-high vacuum scanning tunning microscopy (STM) detection of molecules deposited on Si(111)7x7 surfaces9. The first technique is promising for detection of large bio-molecules as insulin and homoglobin generated in molecular beams after supersonic cooling and pulsed laser desorption. The second technique beatuifully combines the delocalized wave nature and the localized particle character of single C60 molecules in a single picture - and may open the way to non-contact controlled deposition of large molecules on surfaces for device fabrication using such molecular building blocks and molecular lithography.

1 S. Gerlich, M. Gring, H. Ulbricht, K. Hornberger, J. Tuxen, M. Mayor, and M. Arndt, Angew Chem Int Edit 47, 6195 (2008).
2 M. Arndt, M. Berninger, S. Deachapunya, S. Gerlich, L. Hackermuller, A. G. Major, M. Marksteiner, A. Stefanov, and H. Ulbricht, European Physical Journal-Special Topics 159, 1 (2008).
3 H. Ulbricht, M. Berninger, S. Deachapunya, A. Stefanov, and M. Arndt, Nanotechnology 19 (2008).
4 H. Ulbricht, M. Arndt, and N. Gotsche, edited by W. I. P. Organization, PCT, 2009), Vol. WO2009/000285 A1.
5 B. Brezger, L. Hackermuller, S. Uttenthaler, J. Petschinka, M. Arndt, and A. Zeilinger, Phys Rev Lett 88 (2002).
6 S. Gerlich, et al., Nature Physics 3, 711 (2007).
7 K. Hornberger, S. Gerlich, H. Ulbricht, L. Hackermuller, S. Nimmrichter, I. V. Goldt, O. Boltalina, and M. Arndt, New J Phys 11 (2009).
8 M. Marksteiner, A. Divochiy, M. Sclafani, P. Haslinger, H. Ulbricht, A. Korneev, A. Semenov, G. Gol'tsman, and M. Arndt, Nanotechnology 10, 455501 (2009).
9 T. Juffmann, S. Truppe, P. Geyer, A. G. Major, S. Deachapunya, H. Ulbricht, and M. Arndt, Phys Rev Lett 103, 263601 (2009).

Dressed rf atom trapping
10th February Dr. Barry M. Garraway University of Sussex

Dressed rf atom traps use adiabatic potentials formed from static and oscillating magnetic fields. The resulting traps are versatile and varied in shape. The talk will give an overview of the field and report on recent theoretical and experimental developments including possible multi-photon effects.

The bleeding edge of classical mechanics: An experimental demonstration of classical Hamiltonian monodromy.
17th February Mr Thomas Billam Journal Club Seminar

Hamiltonian monodromy is a subtle effect that lurks in the shadows of classical mechanics; often present in the formalism, it rarely rears its head in the form of observable dynamical consequences. However, in a recent paper N. J. Fitch et al. [Phys. Rev. Lett. 103, 034301 (2009)] present an elegant experimental observation of the dynamical effects of exactly such monodromy in a very simple mechanical system: the 1:1:2 resonant elastic pendulum, or 'swing-spring'. Following a general introduction to the concept of Hamiltonian monodromy, I will describe the dynamics of the 1:1:2 resonant elastic pendulum. I will focus in particular on how these dynamics differ from those of the simpler, non-elastic 1:1 resonant pendulum, and how monodromy appears (or disappears) as one transits between these systems. After describing the dynamical effects of monodromy in the 1:1:2 resonant elastic pendulum, and the experimental methods used to observe them, I will briefly survey other systems containing monodromy, including some examples of quantum monodromy in atomic and molecular physics.

Anderson localization in BECs
24th February Mr Graham Lochead Journal Club Seminar

Understanding the role of disorder in condensed matter systems can be difficult, thus recent work has been done in the field of controllable cold quantum gases to try and mimic these systems. This talk will review two recent experimental observations in this field.

Quantum Superposition of Living Organisms
3rd March Mr Daniel Jenkin Journal Club Seminar

Superposition states are one of the many striking features of quantum mechanics and have already been demonstrated in simple systems, however more recently there have been many similar experiments concerned with more complex systems, such as atoms, molecules, and Cooper pairs. Currently there is also progress towards cooling a macroscopic object to the ground state of mechanical motion, allowing testing of quantal phenomena on larger scales. Combining the two fields may allow the creation of a superposition state of a dielectric object.

In a recent paper submitted to the arXivs (0909.1469v2) there is discussion of the potential to examine the superposition of living organisms in order to investigate the 'role of life and conciousness' in quantum mechanics. In this talk I will aim to review to relevant fields and discuss the main points that this paper raises, as well as looking at the feasibility of the proposal.

MPhys Project Talks
10th March

There will be no seminar this Wednesday as the Level 4 project talks will be held throughout the week. The timetable for the talks can be found here.

A Rydberg Quantum Simulator
17th March Mr. Hendrik Weimer University of Stuttgart

A universal quantum simulator is a controlled quantum device which efficiently reproduces the dynamics of any other many particle quantum system with short range interactions. Based on a recent proposal for a many-body gate using strong interactions between Rydberg atoms [1], we present an implementation of a digital quantum simulator in an optical lattice with large lattice spacing [2]. Special focus is on the efficient simulation of Hamiltonians with local many-body interactions, including exotic spin models such as Kitaev's toric code, string nets, and lattice gauge theories. In addition, we show that the formalism also provides the simulation of dissipative terms taking the Lindblad form with many-body jump operators. These dissipative terms allow for the efficient ground state cooling and state preparation.

[1] M. Müller, I. Lesanovsky, H. Weimer, H. P. Büchler, P. Zoller, Phys. Rev. Lett. 102, 170502 (2009).
[2] H. Weimer, M. Müller, I. Lesanovsky, P. Zoller, H. P. Büchler, Nature Phys. (accepted), arXiv:0907.1657

Room Bookings for Ph30 are made by contacting Ian Buckingham at Student Planning and Assessment by internal phone number: 46430
This can be viewed online at: http://timetable.dur.ac.uk/room_dur.htm
Select Room: D/PH30 (106)
Room is currently booked for weeks: 10-19, 25-33, 39-47.