Stimulated Raman Adiabatic Passage (STIRAP) as a Route to Achieving Optical Control in Plasmonics

Optical properties of ensembles of three-level quantum emitters coupled to plasmonic systems are investigated employing a self-consistent model. It is shown that stimulated Raman adiabatic passage (STIRAP) technique can be successfully adopted to control optical properties of hybrid materials with collective effects present and playing an important role in light-matter interactions. We consider a core-shell nanowire comprised of a silver core and a shell of coupled quantum emitters and utilize STIRAP scheme to control scattering efficiency of such a system in a frequency and spatial dependent manner. After the STIRAP induced population transfer to the final state takes place, the core-shell nanowire exhibits two sets of Rabi splittings with Fano lineshapes indicating strong interactions between two different atomic transitions driven by plasmon near-fields.Comment: 11 pages, 6 figures, accepted, Physical Review

Sub-eV scalar dark matter through the super-renormalizable Higgs portal

The Higgs portal of the Standard Model provides the opportunity for coupling to a very light scalar field $\phi$ via the super-renormalizable operator $\phi(H^\dagger H)$. This allows for the existence of a very light scalar dark matter that has coherent interaction with the Standard Model particles and yet has its mass protected against radiative corrections. We analyze ensuing constraints from the fifth-force measurements, along with the cosmological requirements. We find that the detectable level of the fifth-force can be achieved in models with low inflationary scales, and certain amount of fine-tuning in the initial deviation of $\phi$ from its minimum.Comment: 6 pages, 3 figures. References added in the revised version

Anisotropic relaxation in NADH excited states studied by polarization-modulation pump-probe transient spectroscopy

We present the results of experimental and theoretical studies of fast anisotropic relaxation and rotational diffusion in the first electron excited state of biological coenzyme NADH in water-ethanol solutions. The experiments have been carried out by means of a novel polarization-modulation transient method and fluorescence polarization spectroscopy. For interpretation of the experimental results a model of the anisotropic relaxation in terms of scalar and vector properties of transition dipole moments and based on the Born-Oppenheimer approximation has been developed. The results obtained suggest that the dynamics of anisotropic rovibronic relaxation in NADH under excitation with 100~fs pump laser pulses can be characterised by a single vibration relaxation time $\tau_v$ laying in the range 2--15~ps and a single rotation diffusion time $\tau_r$ laying in the range 100--450~ps a subject of ethanol concentration. The dependence of the times $\tau_v$ and $\tau_r$ on the solution polarity (static permittivity) and viscosity has been determined and analyzed. Limiting values of an important parameter $\langle P_2(\cos\theta(t))\rangle$ describing the rotation of the transition dipole moment in the course of vibrational relaxation has been determined from experiment as function of the ethanol concentration and analyzed.Comment: 14 pages, 13 figure

Giant Magneto-Oscillations of Electric-Field-Induced Spin Polarization in 2DEG

We consider a disordered two-dimensional electron gas with spin-orbit coupling placed in a perpendicular magnetic field and calculate the magnitude and direction of the electric-field-induced spin polarization. We find that in strong magnetic fields the polarization becomes an oscillatory function of the magnetic field and that the amplitude of these oscillations is parametrically larger than the polarization at zero magnetic field. We show that the enhanced amplitude of the polarization is a consequence of strong electron-hole asymmetry in a quantizing magnetic field.Comment: 6 pages, 3 figure

N=4, 3D Supersymmetric Quantum Mechanics in Non-Abelian Monopole Background

Using the harmonic superspace approach, we construct the three-dimensional N=4 supersymmetric quantum mechanics of the supermultiplet (3,4,1) coupled to an external SU(2) gauge field. The off-shell N=4 supersymmetry requires the gauge field to be a static form of the 't Hooft ansatz for the 4D self-dual SU(2) gauge fields, that is a particular solution of Bogomolny equations for BPS monopoles. We present the explicit form of the corresponding superfield and component actions, as well as of the quantum Hamiltonian and N=4 supercharges. The latter can be used to describe a more general N=4 mechanics system, with an arbitrary BPS monopole background and on-shell N=4 supersymmetry. The essential feature of our construction is the use of semi-dynamical spin (4,4,0) multiplet with the Wess-Zumino type action.Comment: 16 pages, reference added, published versio