62 citations · 276 across the 13 of their papers we have counts for
13 papers
High-fidelity quantum state control of a polar molecular ion in a cryogenic environment
Dalton Chaffee, Baruch Margulis, April Sheffield +5
We use a quantum-logic spectroscopy (QLS) protocol to control the quantum state of a CaH+ ion in a cryogenic environment, in which reduced thermal radiation extends rotational stat…
Trapping, cooling, and photodissociation analysis of state-selected H ions produced by (3+1) multiphoton ionization
Julian Schmidt, Thomas Louvradoux, Johannes Heinrich +4
We report on the production of cold, state-selected H molecular ions in a linear RF trap. The ions are produced by (3+1) resonance-enhanced multi-photon ionisation (REMPI) of…
Mass-selective removal of ions from Paul traps using parametric excitation
Julian Schmidt, Daniel Hönig, Pascal Weckesser +3
We study a method for mass-selective removal of ions from a Paul trap by parametric excitation. This can be achieved by applying an oscillating electric quadrupole field at twice t…
The Massless Nelson Hamiltonian and its Domain
Julian Schmidt
In the theory of point interactions, one is given a formal expression for a quantum mechanical Hamiltonian. The interaction terms of the Hamiltonian are singular: they can not be r…
Interior-Boundary Conditions for Many-Body Dirac Operators and Codimension-1 Boundaries
Julian Schmidt, Stefan Teufel, Roderich Tumulka
We are dealing with boundary conditions for Dirac-type operators, i.e., first order differential operators with matrix-valued coefficients, including in particular physical many-bo…
On a Direct Description of Pseudorelativistic Nelson Hamiltonians
Julian Schmidt
Abstract interior-boundary conditions (IBC's) allow for the direct description of the domain and the action of Hamiltonians for a certain class of ultraviolet-divergent models in Q…
Complex Charges, Time Reversal Asymmetry, and Interior-Boundary Conditions in Quantum Field Theory
Julian Schmidt, Roderich Tumulka
While fundamental physically realistic Hamiltonians should be invariant under time reversal, time asymmetric Hamiltonians can occur as mathematical possibilities or effective Hamil…
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…
Optical trapping of ion Coulomb crystals
Julian Schmidt, Alexander Lambrecht, Pascal Weckesser +3
The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by…
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…
Long lifetimes in optical ion traps
Alexander Lambrecht, Julian Schmidt, Pascal Weckesser +3
We report on single Barium ions confined in a near-infrared optical dipole trap for up to three seconds in absence of any radio-frequency fields. Additionally, the lifetime in a vi…
A far-off-resonance optical trap for a Ba ion
Thomas Huber, Alexander Lambrecht, Julian Schmidt +2
Optical trapping and ions combine unique advantages of independently striving fields of research. Light fields can form versatile potential landscapes, such as optical lattices, fo…
Simulation of stationary Gaussian noise with regard to the Langevin equation with memory effect
Julian Schmidt, Alex Meistrenko, Hendrik van Hees +1
We present an efficient method for simulating a stationary Gaussian noise with an arbitrary covariance function and then study numerically the impact of time-correlated noise on th…