We combine theoretical and experimental efforts to propose a method for studying energy fluctuations, in particular, obtain the related bistochastic matrix of transition probabilities by means simple measurements at end protocol that drives many-body quantum system out equilibrium. This scheme is integrated with numerical optimizations order ensure proper analysis data, leading physical probabi...

Blackbody radiation BBR shifts of the P0S0 clock transition in the divalent atoms Mg, Ca, Sr, and Yb are evaluated. The dominant electric-dipole contributions are computed using accurate relativistic many-body techniques of atomic structure. At room temperatures, the resulting uncertainties in the E1 BBR shifts are large and substantially affect the projected 10−18 fractional accuracy of the op...

The excitation energies of ns, np, nd, and nf n 6 states in neutral lithium are evaluated within the framework of relativistic many-body theory. First-, second-, third-, and all-order Coulomb energies and firstand second-order Breit corrections to energies are calculated. All-order calculations of reduced matrix elements, oscillator strengths, transition rates, and lifetimes are given for level...

I first give an overview of the thesis and Matrix Product States (MPS) representation of quantum spin systems on a line with an improvement on the notation. The rest of this thesis is divided into two parts. The first part is devoted to eigenvalues of quantum many-body systems (QMBS). I introduce Isotropic Entanglement (IE) and show that the distribution of QMBS with generic interactions can be...

The notion of Thouless energy plays a central role in the theory Anderson localization. We investigate scaling across many-body localization (MBL) transition Floquet model. use combination methods that are reliable on ergodic side (e.g., spectral form factor) and work MBL (e.g. typical matrix elements local operators) to obtain complete picture behavior transition. On side, tends value independ...