Experimental Physics & Research Engineering on Joe Wiedemann

My Personal Portfolio Website with CI/CD

Sun, 10 May 2026 00:00:00 +0000

It’s the site you’re on!

I enjoy homelabbing to have a nice sandbox to learn about programming. I wanted to learn about Continuous Integration/Continuous Deployment (CI/CD) pipelines, so I thought a pipeline that used a static-site generator (SSG) in a Docker container would be a fun project. The site is built around Hugo, an SSG that converts markdown files into the content you see, which builds on my homelab server and is then pushed to a Digital Ocean Container Registry as the last part of my CI/CD pipeline.

PXS Microwave Electronics

Sun, 15 Feb 2026 00:00:00 +0000

PXS Electronics Work

As we develop new state-of-the-art amplifier technology for sub-GHz bands, we have needed to develop supporting infrastructure for the auxillary components that make up the rest of our read out chain. Two of the standout infrastructure pieces has been designing room-temperature analog circuitry that controls a cryogenic multi-pole switch, and designing superconducting lumped-element diplexers. This work is complimentary to the effort to develop high quality coaxial cable - see more on that work in PXS Coax Development.

Coach Pi

Thu, 05 Feb 2026 00:00:00 +0000

Project Inspiration

I made Coach Pi to keep me motivated while getting back into running for fitness. The system is bulit around Gold, Silver, and Bronze goals to give a progressive sense of achievement. The main focus is habit building, with organized races as an approximate scaffolding to guide the training load.

Coach Pi is a personalized running coach that uses local AI to generate daily workout recommendations tailored to your training history, recovery status, and current conditions. In a world of subscription models, Coach Pi runs entirely on local hardware; ensuring your training data stays private while providing intelligent, context-aware guidance.

PXS Cryogenic Coax Development

Tue, 20 Jan 2026 00:00:00 +0000

Coaxial Cable and PXS Readout

High-quality cryogenic coaxial cable is critical to sensitive microwave exferiments. While the expanding market in support of quantum computing has introduced numerous commericial solutions for bulk and/or high-density cable, these offerings remain expensive and require a-priori knowledge of the system design. By developing laboratory methods to fabricate our own cable I was able to reduce lead times and cost, achieve greater freedom in our RF system design, and provide bespoke-level focus that has resulted in leading systematic performance.

Golf Scoreboard App

Tue, 22 Jul 2025 00:00:00 +0000

Project Overview

My Golf Scoreboard is a simple full-stack web application designed for tracking and displaying golf tournament scores in real-time. Built for an outing I took with my friends, the application provided an intuitive interface for scorekeeping and a live leaderboard that updates automatically as teams submit their scores. The system was designed for teams of two, and is configured to be course-aware, meaning it understands the par for each hole and displays scores relative to par (e.g., E, +2, -1), making it easy to see who’s leading at a glance.

Passive pyrolytic graphite heat switch for sub-Kelvin coolers

Fri, 18 Apr 2025 00:00:00 +0000

Motivation

Cryogenic systems have the contradictory requirement of needing high thermal conductivity during the bulk cooldown period, and maximized thermal isolation at the base temperature operation. Heat switches provide a mechanism to change the thermal conductivity between two stages. A typical design is to use a gas-gap heat switch which uses a heater to expel Helium gas as a conduction mechanism between the two sides of the switch. These active switches can be costly and require additional DC wiring instrumentation in the cryostat. For large thermal masses in bulk cooldown, this can be an excessive effort to accelerate the cooldown process. However, pyrolytic graphite sheet demonstrates passive heat switch capabilities as the phonons freeze out and create minimal loading at base temperature. By analyzing the cryogenic performance of a custom-designed graphite heat switch, we were able to implement heat switches that sped up our bulk cooldown from ~4 days to ~2 days for less than 10% the cost of a gas-gap heat switch and without additional wiring instrumentation.

PXS Software Development

Mon, 10 Mar 2025 00:00:00 +0000

PXS Software needs

Because the Princeton Axion Search is a new lab at the university, we have had to develop the infrastruture that enables the scientific research. We strongly value flexibility and control, so we opt for open source or homebrew solutions whenever possible. Particularly in the context of a research lab, designing systems that work across various operating systems, integrate with numerous decades of technology, and can are maintainable has proven to be an excellent opportunity to learn about system design.

Doctor of Philosophy

Sun, 15 Dec 2024 00:00:00 +0000

Dissertation Research

Princeton University
Anticipated Defense: December 2026

My thesis work has been in operationalizing sub-GHz Kinetic Inductance Traveling Wave Parametric Amplifiers (KI-TWPAs) for the Princeton Axion Search (PXS). PXS is laboratory-scale search for a dark matter particle candidate, the axion, at mass ranges the correspond to the transitional region between lumped-element and cavity haloscope search techniques.

The PXS search range poses unique challenges in developing quantum-limited readout schemes. The sensitivity requirements demand noise levels that approach the quantum limit, and significant operational bandwidth as the experiment sweeps through the search regime. Commerically available high electron mobility transistor (HEMT) amplifiers posses the bandwidth, but are 100 to 1000x above the target noise performance. Reflection-based, parametric amplifiers such as Josephson Parametric Amplifiers meet the noise requirements, but have narrow bandwidth that requires tuning prodedures that lead to significant experiment downtime.

Vapor cell Rydberg atom electrometry with time-separated fields

Mon, 10 Jun 2024 00:00:00 +0000

Motivation

Quantum metrology demonstrates that atomic references for precision measurements have exceptional sensitivity and self-calibrating behavior. Microwave sensing in particular is reliant on antenna calibration and requires sophisticated signal processing to attempt to distinguish between incoherent thermal radiation and coherent fields. Prior to this work, state-of-the-art microwave sensitivity measurements using atomic vapors relied on experimental techniques to reduce the laser linewidth, as the optical linewidths dominate the atomic linewidths by many orders of magnitude. This work applied techniques from NMR to decouple the sensitivity from the optics: which is enabled by the long lifetime of the Rydberg state.

PXS Cryogenics

Wed, 10 Apr 2024 00:00:00 +0000

PXS Cryogenic Requirements

The Princeton Axion Search is a cavity Haloscope-style experiment, which requires cryogenic solutions to cool a superconducting magnet storing 6 mega-joules of energy, while simultaneously bringing the cavity detector and readout electronics to 40 milli-Kelvin (40 thousandths of a degree above absolute zero). Similar systems that cool large magnets, like MRI machiens, cool the magnet down by containing the system in a liquid Helium bath. These liquid helium baths are expensive and require sophisticated pressure vessels to handle the forces in case a magnet disruption rapidly boils the liquid Helium. As an academic research group, these requirements for liquid Helium designs would make the experiment prohibitively expensive. We are designing the experiment to be cooled entirely through conduction paths to pulse tube cryocoolers.

Master of Arts

Fri, 20 Jan 2023 00:00:00 +0000

Master of Arts in Physics

Princeton University
Awarded: January 2023

Atomic-based measurement systems provide exceptional sensitivity and create self-calibrating measurements because they utilize fundamental properties of a given atomic species. Developing atom-based sensors for microwave fields creates much more sensitive antennas, and removes the need to calibrate the specific antenna sensitivity. Rydberg atoms are atoms in highly excited states, which makes nearby energy states accessible with microwave fields. Depending on the atomic species and energy level, these systems can be designed for a range of frequencies such as 10 GHz all the way to 100 GHz. The primary drawback is the sensivity of these systems is limited by the linewidth of the lasers that drive the atoms into their energy state. There are solutions for exceptionally narrow laser linewidths, but they are very expensive and make it difficult to re-package this architecture.

Rydberg Atom Dark Evolution Sensing (RADES)

Sat, 01 Jan 2022 00:00:00 +0000

Project Summary

This research project focused on developing novel experimental techniques for Rydberg atom electrometry, specifically implementing time-separated field procedures to establish new sensitivity standards. The work utilized Rydberg atom dark evolution sensing (RADES) to achieve unprecedented electric field sensitivity.

Research Objectives

The primary goal was to develop and demonstrate improved electric field sensitivity standards using Rydberg atoms, with applications in quantum metrology and precision measurements.

Key Achievements

Achieved 10nV/cm/√Hz sensitivity at 10GHz using Rydberg atom dark evolution sensing
Developed time-separated field procedures for improved measurement precision
Established new sensitivity standards for Rydberg atom electrometry

Impact

This work contributed to advancing the field of quantum metrology and established new benchmarks for electric field sensitivity measurements. The techniques developed have applications in precision measurements and fundamental physics research.

Bachelor of Science

Fri, 28 May 2021 00:00:00 +0000

Bachelor of Science in Physics, with Honors

United States Naval Academy
Graduated: May 2021

Completed undergraduate studies at the United States Naval Academy with a focus on fundamentals of physics research, tabletop optics, and simulating open quantum systems. Because the Naval Academy is exclusively an undergraduate institution, I was able to get involved with research as early as the spring semester of my first year. Summer trainings that were a part of my education provided meaningful opportunities to see the challenges of integrating emergent technologies in real applications.

Superradiance of Few Driven Two-Level Quantum Dot Emitters in the Bad Cavity Limit

Mon, 10 May 2021 00:00:00 +0000

Project Summary

Senior thesis work in extracting coupling parameters for demonstrated superradiance from strain-tuned quantum dots in a Naval Research Labs experiment. For this work, the entire simulation was written in MATLAB for Hilbert spaces that represent distinguishable emitters and represented by total angular momentum. Computations were ran primarily locally.

Objectives

The simulation work focused on:

Creating a first-principles models to re-create experimental results from NRL collaborators
Writing a master equation suite to develop simulation of a quantum system connected to an adiabatic bath
Developed wrappers to scale coupling operators to arbitrary hilbert space
Evaluated Superradiant behavior based on second-order photon correlation
Developed mechanisms to evaluate effects of coherent and incoherent driving fields

Featured plots

Ultimately the master-equation model was able to match the experimental data taken by the Naval Research Lab using only 4 free parameters.

Scintillation of laser beams carrying orbital angular momentum propagating in a near-maritime environment

Sun, 01 Mar 2020 00:00:00 +0000

Summary

This work found preliminary evidence that imparting orbital angular momentum onto Gaussian-mode laser beams can weakly improve their intensity stability in atmospheric turbulence. The experiment required building an 890-meter optical link across the Severn River and co-aligning it with a scintillometer to characterize the atmosphere during each measurement.

This work was published in Optics Communications and presented at the Directed Energy Professional Society conference.

Key Contributions

Compared a Gaussian beam with OAM beams carrying topological charges of 1, 6, and 8
Measured beam scintillation across a real near-maritime link under varied atmospheric conditions
Observed a weak reduction in scintillation index as topological charge increased
Identified the additional measurement scale needed to improve statistical significance

Link to Work

This publication is from the Scintillation of Laser Beams Carrying Orbital Angular Momentum project.

Scintillation of Laser Beams carrying OAM

Mon, 10 Feb 2020 00:00:00 +0000

Project Summary

This research project investigated whether imparting Orbital Angular Momentum (OAM) onto Gaussian mode laser beams improves their intensity stability when propagating through atmospheric turbulence. The work was conducted in a near-maritime environment, requiring the construction of a long-range optical link.

Research Objectives

The primary goal was to determine if OAM-carrying beams exhibit improved resistance to scintillation effects compared to standard Gaussian beams when propagating through turbulent atmospheric conditions.

Contact

Mon, 01 Jan 0001 00:00:00 +0000

If you would like to discuss research, my personal projects, or just say hello - please use the form below! I will do my best to reply as quick as possible.

Experimental Physics & Research Engineering on Joe Wiedemann

My Personal Portfolio Website with CI/CD

It’s the site you’re on!

PXS Microwave Electronics

PXS Electronics Work

Coach Pi

Project Inspiration

PXS Cryogenic Coax Development

Coaxial Cable and PXS Readout

Golf Scoreboard App

Project Overview

Passive pyrolytic graphite heat switch for sub-Kelvin coolers

Motivation

PXS Software Development

PXS Software needs

Doctor of Philosophy

Dissertation Research

Vapor cell Rydberg atom electrometry with time-separated fields

Motivation

PXS Cryogenics

PXS Cryogenic Requirements

Master of Arts

Master of Arts in Physics

Rydberg Atom Dark Evolution Sensing (RADES)

Project Summary

Research Objectives

Key Achievements

Impact

Bachelor of Science

Bachelor of Science in Physics, with Honors

Superradiance of Few Driven Two-Level Quantum Dot Emitters in the Bad Cavity Limit

Project Summary

Objectives

Featured plots

Scintillation of laser beams carrying orbital angular momentum propagating in a near-maritime environment

Summary

Key Contributions

Link to Work

Related Work

Scintillation of Laser Beams carrying OAM

Project Summary

Research Objectives

Contact