PhD Scholarships in Quantum Physics: Quantum Opto-Acoustics, Optomechanics, Microscopy and Computing - DTU Physics

Can a massive crystal be placed in a quantum superposition? Can squeezed light control the motion of a membrane? Can we see structures that conventional microscopes miss – and make fault-tolerant photonic quantum computing possible with today’s imperfect quantum states?

At DTU Physics, we are recruiting four PhD students to explore these challenges through three experimental projects and one theory-and-software project. The positions are based in the Section for Quantum Physics and Information Technology (QPIT) and bigQ – Center for Macroscopic Quantum States. You will join an international research environment combining advanced quantum-optical laboratories, quantum information theory and large-scale computational research.

The PhD projects

Each position addresses a different frontier in quantum science. You may apply for one or several projects; please indicate your preferences and explain how your background matches the chosen research direction(s).

Quantum Control of Macroscopic Mechanical Motion (Quantum Opto-Acoustics): How far can quantum mechanics be pushed toward the macroscopic world? Our experiment uses cavity-enhanced Brillouin interactions to control a 12 GHz acoustic mode in a millimeter-sized quartz crystal with an effective mass of 170 micrograms, already cooled extremely close to its quantum ground state. You will develop quantum-control and optical readout techniques to create non-classical mechanical states, including single-phonon excitations and Schrödinger-cat superpositions. You will also explore optical–acoustic entanglement and quantum memories, aiming to turn a massive crystal into a resource for quantum information and fundamental tests of quantum physics.

Quantum-Enhanced Optomechanics with Ultracoherent Membranes: Can we transfer the quantum properties of light to a vibrating membrane? This project builds on our density-phononic-crystal membrane in a high-finesse optical cavity, combining a mechanical quality factor above 100 million with exceptionally strong optomechanical interactions at room temperature. You will develop quantum-limited measurements, suppress technical noise, and implement optical cooling and feedback to approach the mechanical ground state. A central ambition is to interface the membrane with squeezed light, enabling mechanical squeezing, light–mechanics entanglement, and ultimately coherent quantum-state transfer.

Quantum-Enhanced Microscopy through Spatial-Mode Engineering: Can we distinguish microscopic objects that conventional microscopes cannot resolve? This project explores spatial-mode demultiplexing (SPADE), a technique for extracting spatial information inaccessible to conventional intensity imaging. You will develop advanced optical measurements to improve nanoparticle detection and localization using Rayleigh scattering microscopy, and extend these methods to chemically selective Raman microscopy. By combining spatial-mode engineering, quantum estimation theory, and squeezed light, you will pursue improved imaging sensitivity and resolution, with applications in nanoscale sensing, chemical analysis, and biomedical diagnostics.

Fault-Tolerant Continuous-Variable Quantum Computing with GKP States: How much squeezing does a practical fault-tolerant optical quantum computer really need? This theory-and-software project aims to develop architectures for continuous-variable quantum computing based on Gottesman–Kitaev–Preskill (GKP) states, targeting reliable computation below established squeezing thresholds. You will investigate improved GKP decoding, dual-level quantum error correction, optimized logical codes, and simplified measurement-based circuits. Using large-scale simulations and Danish high-performance computing infrastructure, you will develop open benchmarking software and evaluate realistic noise models and logical workloads, establishing a practical roadmap toward scalable photonic quantum computing.