arXiv subjects

Colin Parker

Publications and source records attributed to Colin Parker.

3 recordsLinked to original sources

arXiv2024

A Customizable Modular Control System for Ultracold Experiments

We implemented a control system for ultracold atom experiments. The system includes hardware modules that generate synchronized experiment signals of different kinds, and a protocol to communicate with all the modules. We also implemented software that can automatically generate experiment sequences from declarative tables of parameters with variations. Both the hardware and the software are open-source for adaptation and customization in other experiment platforms.

physics.atom-ph↗

arXiv2017

A Modified Construction for a Support Vector Classifier to Accommodate Class Imbalances

Given a training set with binary classification, the Support Vector Machine identifies the hyperplane maximizing the margin between the two classes of training data. This general formulation is useful in that it can be applied without regard to variance differences between the classes. Ignoring these differences is not optimal, however, as the general SVM will give the class with lower variance an unjustifiably wide berth. This increases the chance of misclassification of the other class and results in an overall loss of predictive performance. An alternate construction is proposed in which the margins of the separating hyperplane are different for each class, each proportional to the standard deviation of its class along the direction perpendicular to the hyperplane. The construction agrees with the SVM in the case of equal class variances. This paper will then examine the impact to the dual representation of the modified constraint equations.

stat.ML↗

arXiv2013

Ultracold mixtures of atomic Li-6 and Cs-133 with tunable interactions

We report the experimental and theoretical study of two-body interactions in a $^{6}$Li-$^{133}$Cs Fermi- Bose mixture. Using a translatable dipole trap setup, we have successfully trapped the two species in the same trap with temperatures of a few microkelvins. By monitoring atom number loss and inter-species thermalization, we identify five s-wave interspecies Feshbach resonances in the lowest two scattering channels. We construct a coupled channels model using molecular potentials to fit and characterize these resonances. Two of the resonances are as wide as 60 G and thus should be suitable for creating Feshbach molecules and searching for universal few-body scaling.

cond-mat.quant-gas↗