Quantum mechanics sets fundamental limits on how precisely we can measure the world—but it also provides tools to push beyond those limits. Our quantum measurement program explores both sides of this coin: understanding where quantum noise constrains sensitivity and engineering quantum states that circumvent those constraints.
**Squeezed light** is our workhorse. By preparing photons in states with reduced uncertainty in one quadrature, we beat the shot-noise limit that would otherwise cap interferometer performance. Advanced LIGO already uses squeezing we helped develop; our current work extends this to frequency-dependent squeezing and filter cavities that tailor the quantum noise reduction across the detector's full bandwidth.
Beyond Gaussian squeezing, we pursue **non-Gaussian quantum resources**—cat states, GKP states, photon-added and photon-subtracted states—that promise even larger metrological gains for specific tasks. Preparing and preserving these fragile states requires sophisticated quantum control: feedback systems that stabilize optical cavities at the quantum level, adaptive protocols that correct for loss and decoherence in real time.
A flagship project is the **Long Vacuum Beam Guide (VBG)**—a kilometer-scale, ultra-low-loss optical channel designed for distributing quantum states between distant laboratories. The VBG serves as both a testbed for quantum networking and a tool for next-generation interferometry.
This pillar is ideal for those drawn to the intersection of quantum optics, control theory, and precision measurement.
Representative topics
Squeezed and non-Gaussian states for metrology
Vacuum Beam Guide (VBG) quantum link
QNN
PSOMA
WOPA
Projects in this pillar
Waveguide squeezed light source
— Build integrated nonlinear waveguide sources of squeezed light for compact, robust quantum-enhanced interferometry.
Vacuum Beam Guide
— Build and characterize a long-baseline vacuum beam guide as a quantum link between laboratories for interferometry and quantum networking.
For an overview of all pillars and projects, see the
Research Projects page.
