Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userFranck-Condon Effect in Central Spin System
140
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We study the quantum transitions of a central spin surrounded by a collective-spin environment. It is found that the influence of the environmental spins on the absorption spectrum of the central spin can be explained with the analog of the Franck-Condon (FC) effect in conventional electron-phonon interaction system. Here, the collective spins of the environment behave as the vibrational mode, which makes the electron to be transitioned mainly with the so-called vertical transitions in the conventional FC effect. The vertical transition for the central spin in the spin environment manifests as, the certain collective spin states of the environment is favored, which corresponds to the minimal change in the average of the total spin angular momentum.
rate research
Read More
We show that for a quantum system coupled to both vibrational and electromagnetic environments, enforcing additivity of their combined influences results in non-equilibrium dynamics that does not respect the Franck-Condon principle. We overcome this shortcoming by employing a collective coordinate representation of the vibrational environment, which permits the derivation of a non-additive master equation. When applied to a two-level emitter our treatment predicts decreasing photon emission rates with increasing vibrational coupling, consistent with Franck-Condon physics. In contrast, the additive approximation predicts the emission rate to be completely insensitive to vibrations. We find that non-additivity also plays a key role in the stationary non-equilibrium model behaviour, enabling two-level population inversion under incoherent electromagnetic excitation.
The Franck-Condon principle governing molecular electronic transitions is utilized to study heavy-quark hadron decays. This provides a direct assessment of the wavefunction of the parent hadron if the momentum distribution of the open-flavor decay products is measured. Model-independent results include an experimental distinction between quarkonium and exotica (hybrids, tetraquarks...), an off-plane correlator signature for tetraquarks and a direct probe of the sea quark orbital wavefunction relevant in the discussion of 3S_1 or 3P_0 decay mechanisms.
The optical properties of a small magnetic cluster are studied in a magnetic version of Frank-Condon principle. This simple model is considered to show new basic physics and could be adopted to treat real problems. The energies and wavefunctions of the cluster are calculated for different spin configurations to evaluate the energies and the strengths of the allowed transitions from the relaxed excited states. The optical de-excitation energies for the likely scenarios are obtained in terms of the exchange parameters of the model.
Understanding the influence of vibrational motion of the atoms on electronic transitions in molecules constitutes a cornerstone of quantum physics, as epitomized by the Franck-Condon principle of spectroscopy. Recent advances in building molecular-electronics devices and nanoelectromechanical systems open a new arena for studying the interaction between mechanical and electronic degrees of freedom in transport at the single-molecule level. The tunneling of electrons through molecules or suspended quantum dots has been shown to excite vibrational modes, or vibrons. Beyond this effect, theory predicts that strong electron-vibron coupling dramatically suppresses the current flow at low biases, a collective behaviour known as Franck-Condon blockade. Here we show measurements on quantum dots formed in suspended single-wall carbon nanotubes revealing a remarkably large electron-vibron coupling and, due to the high quality and unprecedented tunability of our samples, admit a quantitative analysis of vibron-mediated electronic transport in the regime of strong electron-vibron coupling. This allows us to unambiguously demonstrate the Franck-Condon blockade in a suspended nanostructure. The large observed electron-vibron coupling could ultimately be a key ingredient for the detection of quantized mechanical motion. It also emphasizes the unique potential for nanoelectromechanical device applications based on suspended graphene sheets and carbon nanotubes.
Laser induced electronic excitations that spontaneously emit photons and decay directly to the initial ground state (optical cycling transitions) are used in quantum information and precision measurement for state initialization and readout. To extend this primarily atomic technique to organic compounds, we theoretically investigate optical cycling of alkaline earth phenoxides and their functionalized derivatives. We find that optical cycle leakage due to wavefunction mismatch is low in these species, and can be further suppressed by using chemical substitution to boost the electron withdrawing strength of the aromatic molecular ligand through resonance and induction effects. This provides a straightforward way to use chemical functional groups to construct optical cycling moieties for laser cooling, state preparation, and quantum measurement.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
