Apparatus Designed and Built by Physicists who have taught in the Advanced Undergraduate Lab
Quantum Control
NEW!
As a teaching contribution to the
‘second quantum revolution’,
TeachSpin introduces “Quantum Control”,
a table-top apparatus for proton spin manipulation.
Introduction
We are seeing the blossoming of ‘QIST’, quantum information science and technology, and we at TeachSpin appreciate the education and training opportunities that prepare students to participate in the world of ‘quantum machines’. In Quantum Control, we offer an attractively-priced hands-on experiment illustrating the manipulation of quantum states in the simplest possible two-state system of spin-up/spin-down of protons. It’s not a multiqubit quantum computer, but it can certainly be regarded as a one-qubit quantum register. Experiments with this apparatus illustrate the essential role of quantum superposition states, so vital to quantum cryptography, quantum sensors, and quantum computers.
Experiment
Ours is an ‘ensemble experiment’ operating on a whole collection of proton spins, but it shares the layout-in-time of most quantum-information experiments. Our apparatus allows experiments in which, along a timeline, quantum states are first prepared, then evolve freely, and then have a user-chosen ‘intervention’ applied. It’s the Time-Dependent Schrödinger Equation which describes the results of that intervention, which show up farther down the timeline in the read-out phase of the experiment.
Our experimental intervention can be applied with free choices for location in time, duration in time, and amplitude and frequency of perturbation. And the theory of the intervention can be (and needs to be!) carried out non-perturbatively to describe the results it has on the system of proton spins.
This experiment is new and is just going into production. Results from a prototype of the apparatus can be seen below in TeachSpin’s May 2022 Newsletter.