Our publications
2024
In this experiment, we implemented a simple and effective tomography scheme for continuous-variables by optimally sampling the excitation numbers in the cavity. Our method, called ORENS (Optimal Reconstruction via Excitation Number Sampling), outperforms the standard Wigner tomography in cQED and is much more generally applicable to other bosonic systems!
We developed a generalised strategy to perform effective quantum metrology using a single bosonic mode. In the experiment, we show that this protocol is not only versatile, allowing sensitive detection of phase and amplitude variations, but also highly adaptable, enabling us to optimise for the intended metrological goal on demand.
2023
On-demand transposition across light-matter interaction regimes in bosonic cQED
Our latest experimental work on integrating fast flux-tunability with high-Q bosonic cQED devices to harness the distinct interaction regimes of light and matter in a single hardware. It opens many new possibilities in quantum control, bosonic gates, and quantum simulation!
An invited perspective article about the rapidly evolving field of bosonic cQED and its many exciting applications. We had a blast putting this together to share our thoughts about the achievements and challenges of the field, both on the scientific and human aspects.
Continuous-variable Quantum Computation in Circuit QED
Our invited perspective article on quantum computing using continuous-variables in cQED is out! It highlights some of the amazing developments in this area and also the key challenges ahead in realising universal quantum computation using CV-based cQED systems.
https://iopscience.iop.org/article/10.1088/0256-307X/40/11/110303
Enhancing the coherence of cat states by phase-space compression
In qcrew’s first publication, we present a versatile technique for creating robust non-Gaussian continuous-variable resource states in a highly linear bosonic mode and manipulating their phase-space distribution to achieve enhanced resilience against photon loss.
2021
An invited tutorial that aims to provide an outline of the core techniques that underlie most cQED experiments and offer a practical guide for a novice experimentalist to design, construct, and characterize their first quantum device.
2020
An invited review article of the recent developments in quantum error correction with bosonic codes and the progress towards realising fault-tolerant quantum information processing in cQED.
The efficient simulation of molecular vibronic spectra and extraction of the corresponding Franck-Condon factors for photoelectron processes using circuit QED platform.
2019
Entanglement of bosonic modes through an engineered exchange interaction
Implementation of an expotential-SWAP unitary and demonstration of a deterministic entangling gate within quantum error correction codes.
Engineering bilinear mode coupling in circuit QED: Theory and experiment
Theoretical analysis and experimental verification of the characteristics of parametrically-activated SWAP gates between superconducting cavities.
2018
Deterministic teleportation of a quantum gate between two logical qubits
Demonstration of a teleported controlled-NOT (CNOT) gate between two robust and error-correctable modules quantum modules.
Programmable Interference between Two Microwave Quantum Memories
Realisation of a driven, time-dependent bilinear coupling that can be tuned to implement a robust 50∶50 beam splitter between stationary states stored in two superconducting cavities.
2017 & prior
A CNOT gate between multiphoton qubits encoded in two cavities
Demonstration of a controlled NOT (CNOT) gate between two multiphoton qubits in two microwave cavities via parametrically driving a single transmon ancilla, enabling a high-fidelity entangling operation.
Normal-metal quasiparticle traps for superconducting qubits
Theoretical construction and experimentally verification of a model for the effect of a single small trap on the dynamics of the excess quasiparticles injected in a transmon-type qubit as well as the performance of the trap as a function of several key parameters.
A Schrödinger cat living in two boxes
Realisation of a two-mode cat state of electromagnetic fields in two microwave cavities bridged by a superconducting artificial atom, which can also be viewed as an entangled pair of single-cavity cat states.
Suspending superconducting qubits by silicon micromachining
Development of a powerful technique for relieving aluminum 3D transmon qubits from a silicon substrate using micromachining. This technique is a high yield, one-step deep reactive ion etch that requires no additional fabrication processes.
Surface participation and dielectric loss in superconducting qubits
A comprehensive study of the energy relaxation times of superconducting transmon qubits in 3D cavities as a function of dielectric participation ratios of material surfaces, computed by a two-step finite-element simulation and experimentally varied by qubit geometry.
Measurement and control of quasiparticle dynamics in a superconducting qubit
Implementation of a contactless injection technique with unprecedented dynamic range to quantitatively probe the dynamics of quasiparticles in superconducting transmon qubits.
Non-Poissonian Quantum Jumps of a Fluxonium Qubit due to Quasiparticle Excitations
Measurement of the fluctuations in the number of quasiparticle excitations by continuously monitoring the spontaneous quantum jumps between the states of a fluxonium qubit.
SU(3) Quantum Interferometry with Single-Photon Input Pulses
Development of a framework for solving the action of a three-channel passive optical interferometer on single-photon pulse inputs to each channel using SU(3) group-theoretic methods, which can be readily generalized to higher-order photon-coincidence experiments.