ITAMP/HQOC Seminar

Wednesdays at 4:00 PM
Jefferson 250

2016 Fall Schedule

Unless otherwise noted, all events will take place in Jefferson 250

Student presentation begins at 4:00 PM
Refreshments are served from 4:10-4:30 PM
Guest presentation begins at 4:30 PM

 

Wednesday, March 22 – Randall Hulet, Rice University

website: http://atomcool.rice.edu/

Pairing of Spin Polarized Fermi Gases

Ultracold atomic gases are versatile platforms for realizing novel many-body states of matter by virtue of the ability to tune parameters such as interaction, density, dimensionality, and spin-polarization. I will describe experiments that have produced phase diagrams of spin-polarized Fermi gasses in 1D, 3D, and in the 1D-3D dimensional crossover. I will conclude with our progress to create the holy grail of this research, which is the observation of the “elusive” FFLO superfluid state, a state that exhibits coexisting magnetic and superconducting order.

 

Wednesday, March 8 – Ortwin Hess, Imperial College London

website: https://www.imperial.ac.uk/people/o.hess

Controlled Single-Molecule Strong Coupling and Stopped-Light Lasing in Nanoplasmonic Cavities

Recent progress in nanophotonics and metamaterials physics is now allowing us to ‘look inside the wavelength’ and exploit active nano-plasmonics and metamaterials as a new route to quantum many-body optics on the nanoscale [1,2]. At the same time, lasers have become smaller and smaller, reaching with the demonstration of plasmonic nanolasing, scales much smaller than the wavelength of the light they emit [3,4]. Here we discuss recent progress in the study of quantum emitters and quantum gain in nanoplasmonic systems and deliberate on approaches. We combine classical and quantum many-body theory and simulation to describe and model the spatio-temporal dynamics of the optical near field and plasmon polaritons coupled with quantum emitters in nano- plasmonic cavities. We reveal the mechanisms that have allowed us to experimentally reach the strong-coupling regime at room temperature and in ambient conditions [5]. Moreover, it will be demonstrated that applying the nanoplasmonic stopped-light lasing principle to surface- plasmon polaritons (SPP) facilitates trapped/condensed non-equilibrium surface-plasmon polaritons at stopped-light singularities, providing an entry point to SPP-condensation.

[1] O. Hess et al. Nature Materials 11, 573 (2012).
[2] O. Hess et al., Science 339, 654 (2013).
[3] T. Pickering, et al., Nature Communications 5, 4971 (2014).
[4]S. Wuestner, T. Pickering, J. M. Hamm, A. F. Page, A. Pusch and O. Hess, Faraday Discuss. 178, 307 (2015).
[5] R. Chikkaraddy, B. de Nijs, F. Benz, S. J. Barrow, O. A. Sherman, E. Rosta, A. Demetriadou, P. Fox, O. Hess and J.J. Baumberg, Nature 535, 127(2016).

 

Wednesday, November 30 -  Immanuel Bloch, Max Planck Institute of Quantum Optics, Garching; Ludwig-Maximillians University, Munich

website: https://www.quantum-munich.de/people/person-details/pers/1/

Probing Hidden Non-local Antiferromagnetism & Many-Body Localisation Using Ultracold Atoms

Recent experiments with quantum gas microscopes allow for an unprecedented view and control of quantum matter in new parameter regimes and with new probes. In our fermionic quantum gas microscope, we can detect both charge and spin degrees of freedom simultaneously, thereby gaining maximum information about undoped or strongly doped fermionic Hubbard systems. The doped 1D systems are characterised by a hidden non-local antiferromagnetic (AFM) order that can be revealed using non-local string correlators, very similar to the non-local topological order in Spin-1 Haldane chains. The hidden AFM order probed in our experiments is the foundation of spin-charge separation in one-dimensional fermionic systems.

Finally, I will discuss our recent experiments on novel many-body localised (MBL) states of matter that challenge our understanding of the connection between statistical physics and quantum mechanics at a fundamental level. I will also discuss very recent experiments, in which he have observed evidence for Griffith type anomalous slow transport on the ergodic side of the MBL transitions.

 

Wednesday, November 2 -  Mete Atatüre, University of Cambridge

website: http://www.phy.cam.ac.uk/directory/ataturem

Solid-State Spin-Photon Interfaces: Old Friends and New

Optically active spins confined in solids, such as semiconductors or diamond, are interesting and rich physical systems for quantum science and its applications. Their inherently mesoscopic nature leads to a multitude of dynamics within the solid state environment of spins, charges, vibrations and light. While the quantum optics provides a toolbox for advanced spectroscopic investigations for these interaction mechanisms, it also offers solution possibilities for their detrimental effects for the realisation of operational quantum devices. Implementing a high level of control on these constituents and their interactions with each other creates exciting opportunities for realizing stationary and flying qubits within the context of spin-based quantum information science. In this talk, I will provide a snapshot of the progress and challenges for interconnected solid-state spins, as well as first steps towards hybrid quantum devices involving emergent materials.

 

Wednesday, October 19 -  Ferdinand Schmidt-Kaler, Johannes Gutenberg—University of Mainz

website: http://www.quantenbit.de/publications/

Quantum optics and quantum information with trapped ions

The quantum states of ions are perfectly controlled, and may be used for fundamental research in quantum physics, as highlighted by the Nobel Prize given to Dave Wineland in 2012. In this talk, I will highlight the advantages of trapped ions for quantum information processing, taking advantage of modern trap technologies to pave a way for scalability. The laser-ion interactions allow for high fidelity quantum gate operations, while the application of well-suited trap control voltages realizes ion shuttles and the reconfiguration of the ion quantum register. Alternatively, one may employ Rydberg excitation of trapped ions to allow for long-range interactions and quantum gate operation.

 

Wednesday, September 21 – Jelena Vuckovic, Stanford

website: http://web.stanford.edu/~jela/

Quantum Nanophotonics

Nanophotonic structures that localize photons in sub-wavelength volumes are possible today thanks to modern nanofabrication and optical design techniques. Such structures enable studies of new regimes of light-matter interaction, quantum and nonlinear optics, and new applications in computing, communications, and sensing. I will review our recent work on the traditional quantum nanophotonics platform based on InAs quantum dots inside GaAs photonic crystal cavities [1-3], as well as our progress on alternative material systems diamond and silicon carbide [4], which could potentially bring the described experiments to room temperature and facilitate scaling to large networks of resonators and emitters.  Finally, the use of inverse design nanophotonic methods [5], that can efficiently perform physics-guided search through the full parameter space, leads optical devices with properties superior to state of the art, including smaller footprints, better field localization, and novel functionalities.

[1]  Optica, vol. 3, 931-936   (2016)
[2]  Nature Photonics,vol. 10, pp. 163-166  (2016)
[3]  Physical Review Letters,  vol. 114, 233601 (2015)
[4]  Nano Letters, vol. 16 (1), pp. 212-217 (2016)
[5] Nature Photonics 9, 374–377 (2015)

 

 

Wednesday, September 7 – Franco Nori, RIKEN, Saitama, Japan; University of Michigan, Ann Arbor, MI

website: http://www-personal.umich.edu/~nori/ http://dml.riken.jp/

Extraordinary properties of light: Evanescent waves and quantum spin Hall effect

Maxwell’s equations ultimately describe properties of light, from classical electromagnetism to quantum and relativistic aspects. The latter ones result in remarkable geometric and topological phenomena related to spin-1 massless nature of photons. By analyzing fundamental spin properties of Maxwell waves, we show that free-space light exhibits an intrinsic quantum spin Hall effect—surface modes with strong spin-momentum locking. These modes are evanescent waves that form, for example, surface plasmon-polaritons at vacuum-metal interfaces.  Our findings illuminate the unusual transverse spin in evanescent waves and explain recent experiments that have demonstrated the transverse spin-direction locking in the excitation of surface optical modes.

Optical systems combining balanced loss and gain provide a unique platform to implement classical analogues of quantum systems described by non-Hermitian parity–time (PT)-symmetric Hamiltonians. Such systems can be used to create synthetic materials with properties that cannot be attained in materials having only loss or only gain. We report PT-symmetry breaking in coupled optical resonators and observe non-reciprocity in the PT-symmetry-breaking phase due to strong field localization, which significantly enhances nonlinearity. Our results could lead to a new generation of synthetic optical systems enabling on-chip manipulation and control of light propagation.

References:

K.Y. Bliokh, D. Smirnova, F. Nori, Quantum spin Hall effect of light, Science 348, 1448-1451 (2015).
K. Y. Bliokh, A. Y. Bekshaev, F. Nori, Extraordinary momentum and spin in evanescent waves, Nature Communications 5, 3300 (2014).
B. Peng, et al., Parity-time-symmetric whispering-gallery microcavities, Nature Physics 10, 394-398 (2014).

 

 

 

CUA Seminar

Seminars on on Tuesdays at 4:30 PM, with student talk and cookies at 4:00 PM
Alternates between Harvard (J356) and MIT (26-214)

http://cuaweb.mit.edu/Pages/Seminars.aspx


The HQOC does not provide direct support for CUA seminars, but organizers speakers in close collaboration with the CUA, as well as collaborates on special talks, and visitors.

 

 

Harvard Condensed Matter Physics seminar

Unless noted otherwise, seminars are held at noon on Thursdays
Lyman Laboratory, Room 425, Harvard University

http://cmt.harvard.edu/cmpseminar.html


The HQOC fully supports the CMT seminar.

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