Research


  • Distributed quantum information processing using atom-plasmon coupling

  • We aim to create strong electromagnetic coupling between neutral-atoms and localized Plasmons. We are setting up a new experiment to create and use ultracold samples of Strontium atoms for coupling to Plasmonic nanostructures. We aim to experimentally demonstrate these ideas proposed by other groups where it has been shown that, one can achieve strong coupling between atomic two level systems and nano-structures. Currently a setup is being built through funding from Department of Science and Technology to cool and trap Sr atoms. Parallely, we have designed and fabricated silver nanostructures for creating near field optical potentials and these near fields have been measured. The measurements are being validated against numerical simulations. Fig: A) Shows the conceptual schematic of the trapping potentials generated by the nano-disks B) Shows an SEM image of the fabricated silver nanodisks c) Shows an NSOM image of the light field (Image taken at Prof. Achanta Gopal's Group in TIFR, Mumbai)

  • Quantum chaos experiments with atom-optics kicked rotor

  • Superimposing a pulsating 1-D optical lattice onto a sample of ultracold atoms, an Atom-Optic Delta-Kicked Rotor System is being simulated. This work is being carried out in collaboration with the theory group of Dr. M.S. Santhanam (IISER-Pune) A set of ongoing experiments aims at tailoring the coupling of an open quantum system with an engineered environment. Our results show an important feature -- that one can tailor the environment in such a manner that the de-coherence function of a quantum system can be made to follow a power law as opposed to an exponential function. The tailoring of the coupling is built into the statistics of the kicks, where we time interval between the kicks follows a Lèvi distribution with some exponent α. Fig: Schematic of the atom optic kicked rotor and the kick sequence for different Lèvi exponents. Figure taken from Nonexponential Decoherence and Subdiffusion in Atom-Optics Kicked Rotor

  • Atom interferometry with Rb BEC

  • An atom interferometer is a ubiquitous tool for measuring fundamental constants and inertial sensing. Traditional atom interferometers use a cloud of ultra-cold atoms, howeeve a Bose-Einstien condensate(BEC) can further improve the readout of the interferometer. The thermal atom based interferometers also suffer from Dick effect, which limits their ability to probe slow variations in a physical parameter. We are working on an alternative to reduce the dead time of the interferometer by setting up light gratings which split and recombine an atom laser splilled from a 87Rb BEC reservoir, thus enabling a near continuous read-out. We have deomonstrated the first step in this endevour by diffracting an atom laser using a pulsed light grating. The population in different diffraction orders can be controlled precisely by controlling the ON-time of the lattice. Figure taken from Diffraction of an atom laser in the Raman-Nath regime





  • Optical atomic clock based on the narrow linewidth transition in neutral Strontium

  • Atomic clocks based on optical narrow linewidth transitions are paving way for the next generation of time standards. Several of these are already considered as a secondary time standards in International system of units (Le Système International d’Unitès). The relative error in frequency of such clocks is in the 10-19 regime. We plan to set up an optical lattice clock based on the 689 nm narrow linewidth transistion in neutral Strontium. Such lattice clocks have negligible uncertainty that is introduced due to light shift of the trapping dipole beams when the wavelength of the trapping light used is carefully considered (magic wavelength). Fig: Blue MOT beams at 461 nm.

  • Optical tweezer experiments

  • Gravitational wave astronomy and physics in collaboration with IUCAA