# Joshua Foo

Theoretical Physicist, Banting Postdoctoral Fellow

About

I am a theoretical physicist working at the intersection of **quantum mechanics** and **gravity**. I am currently a postdoctoral researcher at Stevens Institute of Technology in the group of Igor Pikovski. I am a recipient of the **Banting Postdoctoral Fellowship**, which I will commence in January 2025 at the University of Waterloo.Previously, I was a postdoctoral researcher in Prof. Timothy Ralph's theory group at the University of Queensland. I completed my PhD, titled **"Fundamental Aspects of Quantum Foundations, Field Theory, and Gravity"**, under the supervision of Prof. Ralph and Dr. Magdalena Zych.

With my daughter in Stockholm, July 2023, for the workshop "Simulating gravity in gedanken and tabletop experiments", co-organised by Igor Pikovski (Stockholm University) and Rivka Bekenstein (Hebrew University of Jerusalem).

Research

My research revolves around aspects of **quantum foundations**, **quantum field theory**, **general relativity**, and **quantum optics**. I am particularly interested in applying the tools of quantum optics and quantum information to study the interplay of gravitational and quantum-mechanical effects in tabletop experiments. Below is a list of my selected publications.

**Relativistic Bohmian trajectories of photons via weak measurements**, Joshua Foo, Estelle Asmodelle, Austin P. Lund, Timothy C. Ralph, Nature Communications 13, 4002 (2022).**Quantum signatures of black hole mass superpositions**, Joshua Foo, Cemile Senem Arabaci, Magdalena Zych, Robert B. Mann, Phys. Rev. Lett 129 (2022).**Telefilters, telemirrors, and causality**, Joshua Foo, Sho Onoe, Magdalena Zych, and Timothy C. Ralph, Phys. Rev. A 105, 3 (2022).

Academic Positions

**From Jan. 2025 Banting Postdoctoral Fellow, University of Waterloo**. Independent research fellowship awarded by National Sciences and Engineering Research Council of Canada. My project is titled "Understanding the quantum physics of spacetime".**Apr. 2023 to Dec. 2024 Postdoctoral Researcher, Stevens Institute of Technology**. Situated in the group of Igor Pikovski, working on general relativistic effects in atomic clocks and novel approaches to quantum sensing.**Oct. 2022 to Mar. 2023 Postdoctoral Researcher, University of Queensland**. Situated in the group of Tim Ralph, working on theoretical quantum optics and quantum foundations.

Education

**Apr. 2019 to Oct. 2022 PhD in Quantum Foundations, Field Theory, and Gravity**. Institution: University of Queensland. Thesis title: "Fundamental Aspects of Quantum Foundations, Field Theory, and Gravity". Supervisors: Prof. Tim Ralph and Dr. Magdalena Zych. Recognitions and awards: shortlisted nationally for Bragg Medal for Excellence in Physics (2023), UQ Best Student Publication Prize (2023), Honourable Mentions in Gravity Research Foundation Essay Competition (2022, 2023).**Apr. 2015 to Dec. 2018 Bachelor of Advanced Science (Honours Class I)**. Institution: University of Queensland. Thesis title: "Generating Negative Energy Densities with an Accelerated Quantum Teleporter". Supervisor: Prof. Tim Ralph. Recognitions and awards: Dean's Commendation (2015-2018), Undergraduate Physics Prize (2017), UCEAP Award for Study Abroad Semester at U.C. Berkeley (2016). Research projects: "Chaotic dynamics of a Bose-Einstein condensate in a double-well potential", w. Prof. Joel Corney, "Detection of a quantum spin liquid via Raman scattering", w. Prof. Ben Powell.

Publications

An up-to-date list of my publications can be found on **Google Scholar**.

22. Witnessing mass-energy equivalence with trapped atom interferometers, Jerzy Paczos, **Joshua Foo**, and Magdalena Zych, arXiv:2406.19037.21. Measurement-based, Lorentz-covariant Bohmian trajectories of multiple photons, **Joshua Foo**, Austin P. Lund, and Timothy C. Ralph, Phys. Rev. A 108 (2023).20. Mass of a weakly measured photon, Yakov Bloch and **Joshua Foo**, Phys. Rev. A 108 (2023).19. Signatures of rotating black holes in quantum superposition, C. Suuryatmadja, C.S. Arabaci, M.P.G. Robbins, **Joshua Foo**, Magdalena Zych, and Robert B. Mann, arXiv:2310.10864.18. Superpositions of thermalisations in relativistic quantum field theory, **Joshua Foo** and Magdalena Zych, arXiv:2307.02593.17. Signatures of discretization in quantum black hole spectra, **Joshua Foo**, Magdelena Zych, and Robert B. Mann, *Honourable Mention in Gravity Research Foundation Essay Competition*.16. Quantum superpositions of Minkowski spacetime, **Joshua Foo**, Cemile Senem Arabaci, Magdalena Zych, and Robert B. Mann, Phys. Rev. D 107 (2023).15. Relativity and decoherence of spacetime superpositions, **Joshua Foo**, Robert B. Mann, and Magdalena Zych, arXiv:2302.03259.14. Quantum signatures of black hole mass superpositions, **Joshua Foo**, Cecile Senem Arabaci, Magdalena Zych, and Robert B. Mann, Phys. Rev. Lett 129 (2022).13. Relativistic Bohmian trajectories of photons via weak measurements, **Joshua Foo**, Estelle Asmodelle, Austin P. Lund, and Timothy C. Ralph, Nature Communications 13 (2022).12. Schrodinger's black hole cat, **Joshua Foo**, Robert B. Mann, and Magdalena Zych, International Journal of Modern Physics D 31 (2022). *Honourable Mention in Gravity Research Foundation Essay Competition*.11. Telefilters, telemirrors, and causality, **Joshua Foo**, Sho Onoe, Magdalena Zych, and Timothy C. Ralph, Phys. Rev. A 105 (2022).10. On the duality of Schwarzshild-de Sitter spacetime and moving mirror, Diego Silvestre-Fernandez, **Joshua Foo**, and Michael R.R. Good, Classical and Quantum Gravity 39 (2022).9. Analog particle production model for general classes of Taub-NUT black holes, **Joshua Foo**, Michael R.R. Good, and Robert B. Mann, Universe 7 (2021).8. Accelerating boundary analog of a Kerr black hole, Michael R.R. Good, **Joshua Foo**, and Eric V. Linder, Classical and Quantum Gravity 38 (2021).7. Hawking radiation particle spectrum of a Kerr-Newman black hole, **Joshua Foo** and Michael R.R. Good, JCAP 19 (2021).6. Entanglement amplification between superposed detectors in flat and curved spacetimes, **Joshua Foo**, Robert B. Mann, and Magdalena Zych, Phys. Rev. D 103 (2021).5. Schrodinger's cat for de Sitter spacetime, **Joshua Foo**, Robert B. Mann, and Magdalena Zych, Classical and Quantum Gravity 38 (2020).4. Thermality, causality, and the quantum-controlled Unruh-deWitt detector, **Joshua Foo**, Sho Onoe, Robert B. Mann, and Magdalena Zych, Phys. Rev. Res. 3 (2020).3. Generating multi-partite vacuum entanglement with a finite-lifetime mirror, **Joshua Foo**, Sho Onoe, Magdalena Zych, and Timothy C. Ralph, New Journal of Physics 22 (2020).2. Continuous-variable quantum teleportation with vacuum-entangled Rindler modes, **Joshua Foo** and Timothy C. Ralph, Phys. Rev. D 101 (2020).1. Unruh-deWitt detectors in quantum superpositions of trajectories, **Joshua Foo**, Sho Onoe, and Magdalena Zych, Phys. Rev. D 102 (2020).

Research Supervision

**Undergraduate & Honours Students**: Alex Tremayne, University of Queensland. Thesis title: "Quantum fields near evaporating black holes" (2023). Gabriel Sorci, Stevens Institute of Technology (2023-present). Finian Casey, University of Queensland. Project title: "Quantum field theory and Bohmian mechanics".**Masters Students**: Cemile Senem Arabaci, University of Waterloo. Thesis title: "Studying black holes in superposition using Unruh-deWitt particle detectors" (2022). Cameron Bellamy, University of Queensland. Project title: "General relativistic photon trajectories via quantum-mechanical weak values and the Schwarzschild-Alcubierre metric" (2023). Yakov Bloch, Bar-Ilan University. Project title: "Mass of a weakly measured photon" (2023).**Ph.D Students**: Cendikiawan Suryaatmadja, University of Waterloo. In progress (2023-present). Thomas Abello, Stevens Institute of Technology. In progress (2023-present).

Journal Refereeing

Physical Review Letters, New Journal of Physics, Classical and Quantum Gravity, Proceedings of the Royal Society A, Communications Physics, Quantum, Journal of Physics A: Mathematical and Theoretical, Entropy, Universe, Symmetry.

Contact

Thank you for visiting my website. You can contact me at [email protected]