34 citations · 223 across the 28 of their papers we have counts for
23 papers · 1 filter
Effective Dynamics for the Bose Polaron in the Large-Volume Mean-Field Limit
Jonas Lampart, Peter Pickl, Siegfried Spruck
We consider the dynamics of the Bose polaron system, a dense quantum gas consisting of bosons evolving in in the presence of an impurity particle. The system is…
Dynamics and equilibrium states of infinite systems of lattice bosons
Andreas Deuchert, Jonas Lampart, Marius Lemm
We consider the dynamics of systems of lattice bosons with infinitely many degrees of freedom. We show that their dynamics defines a group of automorphisms on a --algebra intr…
Ultraviolet Renormalization of Spin Boson Models I. Normal and 2-Nilpotent Interactions
Benjamin Hinrichs, Jonas Lampart, Javier Valentín Martín
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 it…
Equality of magnetization and edge current for interacting lattice fermions at positive temperature
Jonas Lampart, Massimo Moscolari, Stefan Teufel +1
We prove that the magnetization is equal to the edge current in the thermodynamic limit for a large class of models of lattice fermions with finite-range interactions satisfying lo…
The excitation spectrum of a Bose gas with an impurity in the Gross-Pitaevskii regime
Jonas Lampart, Arnaud Triay
We study a dilute system of interacting bosons coupled to an impurity particle via a pair potential in the Gross--Pitaevskii regime. We derive an expansion of the ground state…
A Lower Bound on the Critical Momentum of an Impurity in a Bose-Einstein Condensate
Benjamin Hinrichs, Jonas Lampart
In the Bogoliubov-Fröhlich model, we prove that an impurity immersed in a Bose-Einstein condensate forms a stable quasi-particle when the total momentum is less than its mass times…
Renormalized Bogoliubov Theory for the Nelson Model
Marco Falconi, Jonas Lampart, Nikolai Leopold +1
We consider the time evolution of the renormalized Nelson model, which describes bosons linearly coupled to a quantized scalar field, in the mean-field limit of many particles…
On the global minimum of the energy-momentum relation for the polaron
Jonas Lampart, David Mitrouskas, Krzysztof Myśliwy
For the Fröhlich model of the large polaron, we prove that the ground state energy as a function of the total momentum has a unique global minimum at momentum zero. This implies th…
Hamiltonians for polaron models with subcritical ultraviolet singularities
Jonas Lampart
We treat the ultraviolet problem for polaron-type models in nonrelativistic quantum field theory. Assuming that the dispersion relations of particles and the field have the same gr…
The Nelson Model on Static Spacetimes
Janik Kruse, Jonas Lampart
The Nelson model describes the interaction of nonrelativistic quantum particles with a relativistic quantum field of scalar bosons. Nelson rigorously demonstrated in 1964 the exist…
Dynamics of a tracer particle interacting with excitations of a Bose-Einstein condensate
Jonas Lampart, Peter Pickl
We consider the quantum dynamics of a large number of interacting bosons coupled a tracer particle, i.e. a particle of another kind, on a torus. We assume that in the initial s…
A remark on the attainable set of the Schrödinger equation
Jonas Lampart
We discuss the set of wavefunctions that can be obtained from a given initial condition by applying the flow of the Schrödinger operator and varying the…
A nonrelativistic quantum field theory with point interactions in three dimensions
Jonas Lampart
We construct a Hamiltonian for a quantum-mechanical model of nonrelativistic particles in three dimensions interacting via the creation and annihilation of a second type of nonrela…
On Nelson-type Hamiltonians and abstract boundary conditions
Jonas Lampart, Julian Schmidt
We construct Hamiltonians for systems of nonrelativistic particles linearly coupled to massive scalar bosons using abstract boundary conditions. The construction yields an explicit…
Quantum waveguides with magnetic fields
Stefan Haag, Jonas Lampart, Stefan Teufel
We study generalised quantum waveguides in the presence of moderate and strong external magnetic fields. Applying recent results on the adiabatic limit of the connection Laplacian…
The adiabatic limit of the connection Laplacian
Stefan Haag, Jonas Lampart
We study the behaviour of Laplace-type operators H on a complex vector bundle E M in the adiabatic limit of the base space. This space is a fibre bundle M $\rightarro…
Particle Creation at a Point Source by Means of Interior-Boundary Conditions
Julian Schmidt, Jonas Lampart, Stefan Teufel +1
We consider a way of defining quantum Hamiltonians involving particle creation and annihilation based on an interior-boundary condition (IBC) on the wave function, where the wave f…
Coulomb potentials and Taylor expansions in Time-Dependent Density Functional Theory
Søren Fournais, Jonas Lampart, Mathieu Lewin +1
We investigate when Taylor expansions can be used to prove the Runge-Gross Theorem, which is at the foundation of Time-Dependent Density Functional Theory (TDDFT). We start with a…
Semi-classical Dirac vacuum polarisation in a scalar field
Jonas Lampart, Mathieu Lewin
We study vacuum polarisation effects of a Dirac field coupled to an external scalar field and derive a semi-classical expansion of the regu-larised vacuum energy. The leading order…
A many-body RAGE theorem
Jonas Lampart, Mathieu Lewin
We prove a generalized version of the RAGE theorem for N-body quantum systems. The result states that only bound states of systems with particles persist in the lon…
Generalised Quantum Waveguides
Stefan Haag, Jonas Lampart, Stefan Teufel
We study general quantum waveguides and establish explicit effective Hamiltonians for the Laplacian on these spaces. A conventional quantum waveguide is an -tubular ne…
The adiabatic limit of Schrödinger operators on fibre bundles
Jonas Lampart, Stefan Teufel
We consider Schrödinger operators on a fibre bundle with compact fibres and a metric that blows up directions perpend…
Effective Hamiltonians for Thin Dirichlet Tubes with Varying Cross-Section
Jonas Lampart, Stefan Teufel, Jakob Wachsmuth
We show how to translate recent results on effective Hamiltonians for quantum systems constrained to a submanifold by a sharply peaked potential to quantum systems on thin Dirichle…