Showing items with similar title or keywords.

• In and Out-of-Equilibrium Ab Initio Theory of Electrons and Phonons 

  Stefanucci, Gianluca; van Leeuwen, Robert; Perfetto, Enrico (American Physical Society (APS), 2023)

  In this work, we lay down the ab initio many-body quantum theory of electrons and phonons in equilibrium as well as in steady-state or time-varying settings. Our focus is on the harmonic approximation, but the developed ...

• Application of time-dependent many-body perturbation theory to excitation spectra of selected finite model systems 

  Säkkinen, Niko (University of Jyväskylä, 2016)

  In this thesis, an approximate method introduced to solve time-dependent many-body problems known as time-dependent many-body perturbation theory is studied. Many-body perturbation theory for interacting electrons and ...

• Effective medium theory for the low-temperature heat capacity of a metasolid plate 

  Puurtinen, Tuomas, A.; Maasilta, Ilari, J. (Nature Publishing Group, 2023)

  Nanopatterning can be used to strongly control the thermal properties of solids, but theoretical understanding relies often on complex numerical simulations. Here, an analytical theory is derived for the low temperature ...

• Acoustic wave tunneling across a vacuum gap between two piezoelectric crystals with arbitrary symmetry and orientation 

  Geng, Zhuoran; Maasilta, Ilari J. (American Physical Society (APS), 2022)

  It is not widely appreciated that an acoustic wave can “jump” or “tunnel” across a vacuum gap between two piezoelectric solids, nor has the general case been formulated or studied in detail. Here, we remedy that situation, ...

• Sub- to super-Poissonian crossover of current noise in helical edge states coupled to a spin impurity in a magnetic field 

  Probst, Benedikt; Virtanen, Pauli; Recher, Patrik (American Physical Society (APS), 2022)

  Edge states of two-dimensional topological insulators are helical and single-particle backscattering is prohibited by time-reversal symmetry. In this paper, we show that an isotropic exchange coupling of helical edge states ...