Generation of squeezed phonon states by optical excitation of a quantum dot
نویسندگان
چکیده
A theoretical analysis of the fluctuation properties of optical phonons generated by the optical excitation of a quantum dot is presented. In particular we study whether squeezed states may be generated where either the fluctuations of the displacement or of the momentum fall below the vacuum level. The calculations are based on a generating functions formalism which provides analytical results for the case of excitation by ultrashort optical pulses. While after a single pulse excitation no squeezing occurs we find that after an excitation with two phase-locked pulses phonon states can be created where the uncertainties of displacement or momentum temporarily fall below their vacuum values.
منابع مشابه
Bias-Induced Optical Absorption of Current Carrying Two-Orbital Quantum Dot with Strong Electron-Phonon Interaction (Polaron Regime)
The one photon absorption (OPA) cross section of a current carrying two-orbital quantum dot (QD) with strong electron-phonon interaction (polaron regime) is considered. Using the self-consistent non-equilibrium Hartree-Fock (HF) approximation, we determine the dependence of OPA cross section on the applied bias voltage, the strength of effective electron-electron interaction, and level spacing ...
متن کاملDirectly observing squeezed phonon states with femtosecond x-ray diffraction.
Squeezed states are quantum states of a harmonic oscillator in which the variance of two conjugate variables each oscillate out of phase. Ultrafast optical excitation of crystals can create squeezed phonon states, where the variance of the atomic displacements oscillates due to a sudden change in the interatomic bonding strength. With femtosecond x-ray diffraction we measure squeezing oscillati...
متن کاملQuantum control of polaron states in semiconductor quantum dots
We study phonon-assisted dephasing in optically excited semiconductor quantum dots within the frameworks of the independent Boson model and optimal control. Using a realistic description for the quantum dot states and the phonon coupling, we demonstrate that such dephasing has a drastic impact on the coherent optical response. We employ optimal control theory to search for control strategies th...
متن کاملQuantum Squeezed Light Propagation in an Optical Parity-Time (PT)-Symmetric Structure
We investigate the medium effect of a parity-time (PT)-symmetric bilayer on the quantum optical properties of an incident squeezed light at zero temperature (T=0 K). To do so, we use the canonical quantization approach and describe the amplification and dissipation properties of the constituent layers of the bilayer structure by Lorentz model to analyze the quadrature squeezing of the outgoing ...
متن کاملTunneling current induced phonon generation in nanostructures
We analyze generation of phonons in tunneling structures with two electron states coupled by electron-phonon interaction. The conditions of strong vibration excitations are determined and dependence of non-equilibrium phonon occupation numbers on the applied bias is found. For high vibration excitation levels self consistent theory for the tunneling transport is presented. Tunneling current ind...
متن کامل