Creation and detection of the excited state

J. E. Bayfield

Gagik P. Djotyan, N. Sandor, Joseph S. Bakos +6 more

We propose and analyze a scheme for creation of coherent superposition of meta-stable states in a multilevel atom. The scheme is based on interaction of a frequency modulated (chirped) laser pulse and a pulse of a constant carrier frequency with the atom having two meta-stable (ground) states and multiple excited states. The negligible excitation of the atoms is a priority in the proposed scheme to eliminate the de-coherence processes caused by the decay of the excited states. The scheme is applied to create coherent superposition of magnetic sublevels of ground states of the 87Rb atom taking into account all allowed electric-dipole transitions between magnetic sublevels of the 5 2S1/2 - 52P3/2 transition (D2 line). In addition to the theoretical analysis we consider possible experimental realizations of the proposed coherence creation scheme and discuss their feasibilities and constraints. We concentrate on a detection of the superposition state in the Faraday-rotation experiment. Such detection reduces technical laser noise background and offers high sensitivity of the coherence detection. Moreover, it allows extra control of the atomic sample and the interaction dynamics by external magnetic field.

Alexander A. Bukach, S. Ya. Kilin

A method for creating an entangled state between two NV centers in a diamond that do not interact directly with each other is studied. The method is based on the excitation of centers via a half divider (a 50% beamsplitter) with the subsequent coherent inversion of the spin of the excited center and the detection of a photon emitted by the excited center. The parameters of a multimode single-photon pulse that make it possible to achieve a maximally possible excitation of the centers at a given solid angle of the focusing of the light on the center are found. The probability to create an entangled state in relation to the parameters of the initial state of a photon, the turn-on and turn-off times of the microwave pulse and the light focusing solid angle is determined. Optimal values of these parameters that ensure a maximal probability of the entanglement creation are determined.

Mattia Morgavi, Peter Majcen, Marco Rigobello +2 more

We introduce a method for the selective preparation and detection of quasiparticle wave packets, based on creation operators that generate dressed, localized excitations on top of interacting vacua of (quasi-)one-dimensional quantum lattice theories. This method exploits maximally localized Wannier functions (MLWFs) constructed from quasiparticle bands at intermediate system sizes, enabling the construction of unitary local dressed creation operators. The algorithm allows for species-resolved wave-packet preparation and detection, enabling the separation of known quasiparticle contributions from unknown resonances. We test this approach with matrix product states (MPS) on pure hardcore Hamiltonian QCD on a ladder lattice, detecting scattering outputs and mass resonances.

Tim Wogan

Anonymous