Related papers: Theory of nonlinear microwave absorption by intera…
Tunneling two-level systems (TLSs), generic to amorphous solids, dictate the low-temperature properties of amorphous solids and dominate noise and decoherence in quantum nano-devices. The properties of the TLSs are generally described by…
High-gain microwave amplifiers operating near quantum limit are crucial for development of quantum technology. However, a systematic theoretical modeling and simulations of their performance represent rather challenging tasks due to the…
We present results of theoretical description of ultrasonic phenomena in molecular liquids. In particular, we are interested in the development of microscopical, i.e., statistical-mechanical framework capable to explain the long living…
Using the Activation-Relaxation Technique-nouveau, we search for two-level systems (TLSs) in models of amorphous silicon (a-Si). The TLSs are mechanisms related to internal mechanical dissipation and represent the main source of noise in…
We have analyzed a dissipative two level quantum system (TLS) which is continuously and simultaneously irradiated by a high and low frequency excitation. The interaction of the TLS with a high frequency excitation is considered in the frame…
Rabi frequencies for multiphoton absorption by atoms or molecules that can be characterized as two- or three-level systems are obtained in the cases of single and double laser perturbations. If the ambiguity in the origin of absolute energy…
We continue our work on developing techniques for studying turbulence with spectroscopic data. We show that Doppler-broadened absorption spectral lines, in particularly, saturated absorption lines, can be used within the framework of the…
The two layer model is a 2+1/2 degrees of freedom non autonomous dynamical system whose lower order expansion exhibits capture in resonance, numerically detected in a previous paper by the authors. In this paper, we reframe the model along…
We study the dephasing of an individual high-frequency tunneling two-level system (TLS) due to its interaction with an ensemble of low-frequency thermal TLSs which are described by the standard tunneling model (STM). We show that the…
We use linear response theory in order to compute the light absorption spectrum, in the terahertz band, of a polariton system composed by excitons in a quantum dot very strongly coupled to the lowest photon mode of a thin micropillar. In a…
We consider finite frequency noise in a mesoscopic system with arbitrary interactions, connected to many terminals kept at finite electrochemical potentials. We show that the excess noise, obtained by subtracting the noise at zero voltage…
We study the charge noise $S_Q$ in Josephson qubits produced by fluctuating two level systems (TLS) with electric dipole moments in the substrate. The TLS are driven by an alternating electric field of angular frequency $\Omega$ and…
The recent realization of millisecond-scale coherence with tantalum-on-silicon transmon qubits showed that depositing the Al/AlOx/Al Josephson junction in a high purity, ultrahigh vacuum environment was critical for achieving…
We discuss the absorption spectrum of dirty s-wave superconductors in the nonequilibrium steady state under a homogeneous and monochromatic microwave. In this state, there exists a finite density of states at lower energies than the…
Increasing and stabilizing the coherence of superconducting quantum circuits and resonators is of utmost importance for various technologies ranging from quantum information processors to highly sensitive detectors of low-temperature…
Microscopic two-level system (TLS) defects at dielectric surfaces and interfaces are among the dominant sources of loss in superconducting quantum circuits, and their properties have been extensively probed using superconducting resonators…
Nonlinear absorption in four and five energy level systems have been studied with the aid of steady-state rate equation approach. We report on the tunability of saturable and reverse saturable absorption as a function of spectroscopic…
We study the effect of external driving on the two level systems (TLSs) assumed to be a major obstacle in increasing the coherence time of solid state Josephson-junction qubits. We find, by use of a Bloch-Redfield approach, that external…
Two-level-system (TLS) defects in amorphous dielectrics are a major source of noise and decoherence in solid-state qubits. Gate-dependent non-Markovian errors caused by TLS-qubit coupling are detrimental to fault-tolerant quantum…
We measure the lifetime ($T_{1}$) and coherence ($T_{2}$) of two-level defect states (TLSs) in the insulating barrier of a Josephson phase qubit and compare to the interaction strength between the two systems. We find for the average decay…