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Harnessing higher-dimensional fluctuations in an information engine

We show how an information engine can convert horizontal thermal 鈥渏iggles鈥� (fluctuations) into the lifting of a weight against gravity. Remarkably, horizontal fluctuations turn out to be more valuable than vertical ones. This design modularizes the roles of fluctuation harvesting and energy storage, suggesting a route toward more practical devices

Angle-dependent magnetoresistance including magnetic breakdown

Angle-dependent magnetoresistance (ADMR) is a powerful tool for probing Fermi surfaces of layered metals, providing valuable insights into the physics of quantum materials such as cuprate and organic superconductors. In ADMR experiments, the interlayer electrical resistivity is measured as the orientation of the applied magnetic field changes relative to two-dimensional conducting layers. A related phenomenon, magnetic breakdown, occurs when electrons tunnel between adjacent segments of the Fermi surface at strong magnetic fields. We study the effect of magnetic breakdown on ADMR for realistic Fermi surfaces, which are anisotropic in momentum space and incorporate thermal effects.

An Optically Resolved Hyperfine Interaction at Telecom Wavelengths within the Excited State of Interstitial Aluminum in Silicon

Nuclear-spin qubits in the solid state have demonstrated exceptional coherence times, making them exceptional candidates for quantum hardware. Integrating them into quantum networks requires introducing an efficient optical interface for distributed entanglement, such as the spin-dependent optical transitions of an electron in a silicon colour centre. While typical interfaces rely on paramagnetic ground states, recent studies have explored centres with diamagnetic ground states. In such systems, since hyperfine coupling is exclusively enabled within the excited state, a nuclear spin protection scheme is enabled after the system returns to the ground state. The electron, therefore, operates as an ancillary qubit for nuclear spin initialization and readout for future quantum repeater node.

Coherent optical properties of the silicon T centre

Silicon colour centres have emerged as promising spin-photon interfaces (SPIs) to provide a platform for networked quantum computing and long-distance quantum communications. The T centre is at the forefront of silicon colour centre SPIs with spin-dependent optical emission in the telecommunications O-band. Usage of T centres for quantum computing and communications will require control of both the optical and spin qubits. Though T centre spin control has been demonstrated with RF and MW fields, an all-optical approach would alleviate many technical requirements, substantially lower operational heat loads, and allow fundamentally faster gates. Here, we report progress towards T centre optical control using telecommunications band lasers. We demonstrate optical Rabi oscillations and achieve a significant improvement in optical coherence by reducing spectral diffusion with a resonance checking scheme. We next demonstrate optical coherent population trapping (CPT) in the T centre鈥檚 electron spin. This is the first coherent optical spin preparation on the T centre. Using CPT we perform high resolution optical spectroscopy of the T centre ground state. These results demonstrate the first steps towards optically driven spin control of the silicon T centre.

Investigating Collagen Mechanics and Structure Using AFM

Collagen is the most abundant protein in humans. A single collagen molecule forms a right-handed triple helix from three left-handed polypeptide chains. These helices assemble into fibrils that provide mechanical strength to tissues such as bone, tendon, and skin. This poster includes atomic force microscopy (AFM) images of individual collagen molecules. I trace their contours and analyze conformations to determine persistence length, a measure of molecular stiffness. These results offer insight into collagen mechanics at the single-molecule level and lay the groundwork for resolving finer structural features such as helical pitch. Other techniques, including X-ray crystallography, have revealed atomic-level structure only for short collagen-like peptides; full-length single collagen molecules remain unresolved. AFM offers an alternative approach with the potential to directly visualize the helical pitch. This work supports broader efforts to understand collagen-related genetic disorders such as brittle bone disease and EhlersDanlos syndrome

Optimized numerical evolution of perturbations across sharp background trajectory turns in multifield inflation

Features in the primordial power spectrum require numerical methods that are both accurate and scalable across the wide class of multifield inflationary models that produce them. Sharp turns in the background trajectories, induced by either potential or geometric effects, render these computations particularly challenging. In this work, we introduce an efficient method for evolving primordial scalar fluctuations, requiring timesteps comparable to those used for the background evolution. We demonstrate that the method accurately tracks perturbations through rapidly turning trajectories in arbitrary field-space geometries, enabling systematic exploration of spectral features across diverse multifield scenarios. Our approach scales robustly to large numbers of degrees of freedom, providing a reliable computational framework for probing regimes that significantly depart from slow-roll dynamics.

Increasing Superconducting Critical Temperature of NbTe2 by Improvement of Sample Quality

NbTe2 has been reported with very low superconducting transition critical temperature Tc (0.7K), substantially lower than the NbSe2 (7K). Recently, a newly synthesized single-crystal NbTe2 sample exhibits a higher Tc (1.3K), nearly twice of the previous reported value. In addition, the normal-state transport above about 40 K remains broadly consistent with previous NbTe2 reports, especially the positive and approximately linear Hall response at high temperature. We measured the electrical resistivity, magnetization, magnetic susceptibility and heat capacity. The resistivity measurement resulted in a much stronger low temperature magnetoresistance (170% at 4K, 9T) and a higher residual resistivity ratio (126, 300K vs 1.8K). Besides, there is a clear de Haas-van Alphen quantum oscillation, supporting improved sample quality. Additionally, the low temperature heat capacity measurements show a clear superconducting anomaly, providing thermodynamic evidence for superconductivity is a bulk property rather than being caused by an inhomogeneous or filamentary region

Collagen Imaging using Fluorescent Peptides

Collagen is the major structural component of mammalian tissues and plays a critical role in cell proliferation, migration and differentiation. This unique triple-helical protein undergoes extensive remodeling during many life-threatening diseases including fibrosis, myocardial infarction, and cancer. Detection of excessive degradation of collagen is an important marker of tissue damage, which is essential to the diagnosis and treatment of disease. Conventional collagen detection and targeting tools are difficult to use; an alternative method of detection generating great interest is the use of Collagen Hybridizing Peptides (CHPs) which are fluorescently labelled peptides that detect damaged collagen. CHPs have a repeating Gly-X-Y sequence, the same motif found in natural collagen, which provides a strong affinity to hybridize with unfolded collagen chains. CHPs enable direct localization of collagen damage in tissues. However, much remains to be learned about the mechanisms by which these peptides interact with fibrillar collagen, as well as with gelatin networks. Here, our experiments with fluorescence microscopy demonstrate that CHPs have some affinity for collagen fibrils. They show the importance of the repeating Gly-X-Y sequence, through comparison with experiments using peptides with this sequence order scrambled. We are extending this work to quantify the binding of CHPs to gelatin networks, which contain much higher amounts of damaged collagen. These assays lay the groundwork for future experiments that provide additional insight into the binding mechanism of CHPs.

Towards Long-Distance Free-Space Quantum Channels for Quantum Cryptography

Long-distance free-space optical links are a critical layer for enabling quantum communications in Canada, supporting the inter-networking of regional nodes as well as near-term quantum key distribution. However, atmospheric turbulence over tens to hundreds of kilometres introduces multi-scale aberrations that degrade coupling efficiency and coherence for photon-limited experiments.

Optical tree cluster state generation with the silicon T Centre

Optical cluster states are highly entangled states of light, essential for one-way quantum computation and quantum repeaters, used for long-distance quantum networking [1]. Although small, one-dimensional cluster states have already been demonstrated on multiple platforms [2, 3], large multi-dimensional states are necessary for these technologies to become practical. Silicon colour centres have emerged as a promising spin-photon interface for this task due to their long-lived spin coherence, natural nuclear spin register, narrowband optical emission, and compatibility with the existing silicon nanophotonic industry [4, 5].

Electron emission in the helium ion microscope: thickness metrology of suspended MoS2

Secondary-electron (SE) contrast in the helium ion microscope (HIM) is sensitive to membrane thickness when a transmission-capable geometry is used. We investigate suspended MoS2 on lacey-carbon TEM grids and correlate HIM SE intensity with thickness determined independently by STEM-EELS. The HIM response exhibits a maximum near intermediate thickness and decreases for both thinner and thicker regions, consistent with the SE signal having contributions from both entrance and exit surfaces. Furthermore, multi-factored modeling using SRIM and Markov Chain Monte Carlo (MCMC) simulations reveals that SE emission generated by the He ion beam scattering through the sample and interacting with the microscope interior is a significant source of the overall contrast. This approach provides a rapid thickness screening method for suspended MoS2 and other membranes compatible with routine HIM imaging

Interfacing Telecom Quantum Memories and Satellite Quantum Networks

Quantum memories are essential for quantum networks and the success of entanglement swapping at repeater nodes. Silicon T centres are promising quantum memories due to their long-lived electron and nuclear spin with coherence times of 2.1 ms and 1.1 s, respectively. The T centre possesses a spin-photon interface which produces photons in the telecommunication O-band entangled with these spins. The emitted photons suit fibre quantum networks; however, these networks experience exponential loss with distance and are limited to a few hundred kilometers. For longer distances, free space links involving quantum satellites are a potential solution, but the T centre emitted photons operate outside the relevant satellite communication channels (780 nm 鈥� 930 nm). Utilising the T centre for long-distance quantum networks requires a quantum frequency conversion to shift the O-band photon to the satellite channel while retaining its quantum properties. This poster highlights the quantum frequency conversion process and its characterisation.

Boosting single-photon Bell-state measurements with deterministic ancillae

Bell-state measurements underpin quantum communication, quantum networking, and measurement-based quantum computing. However, their linear-optical implementations are known to succeed with at most 50\% probability for single-photon qubits. This limit could be surpassed by introducing auxiliary photons, but existing proposals employ photonic states that are expensive and probabilistic to generate. In this work, we show that the single-photon Bell-state measurement success rate can be enhanced by utilizing squeezed-vacuum ancillae, which can be deterministically prepared on most photonic platforms. Our scheme achieves a 58.3% success rate with about 6.34 dB squeezing for dual-rail encoding and 54.7% with about 6.55 dB for single-rail encoding. Our schemes can also improve the success probability of ambiguous state discrimination. Our result offers a practical route to improve the efficiency of photonic quantum information processing.

Discrete-Variable-Assisted Error Correction of Continuous-Variable Quantum Information

Quantum information can be encoded as continuous wave functions in bosonic modes, but implementing error correction for such continuous-variable (CV) information remains a significant challenge. In this work, we propose a novel CV quantum error correction (QEC) scheme that leverages auxiliary discrete-variable (DV) systems as resources. By applying appropriate hybrid CV-DV coupling, we show that the fluctuation of mode quadratures induces a geometric phase on the DV system. Measuring the DV system thus enables the estimation and subsequent correction of the CV fluctuation noise. We demonstrate that even a single auxiliary qubit can suppress infidelity by 18%, and further improvement is possible by using a higher-level ancilla. Furthermore, we propose that the DV ancilla can be encoded in noisy bosonic modes with established DV QEC. This introduces a new class of oscillator-in-oscillator code that is fundamentally different from the only known code, which relies on difficult-to-prepare GKP states.