arXiv subjects

Javier Valentín Martín

Publications and source records attributed to Javier Valentín Martín.

4 recordsLinked to original sources

arXiv2026

Non-Trivial Renormalization of Spin-Boson Models with Supercritical Form Factors

In this paper we construct the non-trivial, renormalized Hamiltonian for a class of spin-boson models with supercritical form factors, including the one describing the Weisskopf-Wigner spontaneous emission. The renormalization is performed through both a self-energy and mass renormalization, in the so-called Hamiltonian formalism of constructive quantum field theory, implemented by a non-unitary dressing transformation. This solves the problem of triviality for unitarily-renormalized supercritical spin-boson models.

math-ph↗

arXiv2026

Wave Function Renormalization for Particle-Field Interactions

In this paper, we develop a wave function renormalization scheme for models of non-relativistic quantum particles interacting with a quantized relativistic field, in the Hamiltonian formalism of quantum field theory. We construct the interacting Hamilton operator, in its ground state representation, for a large class of particle-field interactions; hereby addressing a number of open problems related to both ultraviolet and infrared singularities in the spin-boson and Nelson models, where the infinite wave function renormalization plays a fundamental role.

math-ph↗

arXiv2025

Renormalization of generalized spin-boson models with critical ultraviolet divergences

We provide a rigorous construction of generalized spin--boson models with commuting transition matrices and form factors exhibiting critical ultraviolet (UV) divergences. That is, we cover all divergences where a self-energy renormalization, but no non-Fock representation, is required. Our method is based on a direct definition of the renormalized Hamiltonian on a sufficiently large test domain, followed by a Friedrichs extension. We then prove that this Hamiltonian coincides with the one obtained by cut-off renormalization. Furthermore, we show that for specific supercritical cases, i.e., when a non-Fock representation is required, the renormalized Hamiltonian is trivial.

math-ph↗

arXiv2025

Ultraviolet Renormalization of Spin Boson Models I. Normal and 2-Nilpotent Interactions

We study the ultraviolet problem for models of a finite-dimensional quantum mechanical system linearly coupled to a bosonic quantum field, such as the (many-)spin boson model or its rotating-wave approximation. If the state change of the system upon emission or absorption of a boson is either given by a normal matrix or by a 2-nilpotent one, which is the case for the previously named examples, we prove an optimal renormalization result. We complement it, by proving the norm resolvent convergence of appropriately regularized models to the renormalized one. Our method consists of a dressing transformation argument in the normal case and an appropriate interior boundary condition for the 2-nilpotent case.

math-ph↗