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1. Floquet-enhanced spin swaps

   https://doi.org/10.1038/s41467-021-22415-6  

   Qiao, Haifeng; Kandel, Yadav P.; Dyke, John S.; Fallahi, Saeed; Gardner, Geoffrey C.; Manfra, Michael J.; Barnes, Edwin; Nichol, John M. (December 2021, Nature Communications)

   null (Ed.)

   Abstract The transfer of information between quantum systems is essential for quantum communication and computation. In quantum computers, high connectivity between qubits can improve the efficiency of algorithms, assist in error correction, and enable high-fidelity readout. However, as with all quantum gates, operations to transfer information between qubits can suffer from errors associated with spurious interactions and disorder between qubits, among other things. Here, we harness interactions and disorder between qubits to improve a swap operation for spin eigenstates in semiconductor gate-defined quantum-dot spins. We use a system of four electron spins, which we configure as two exchange-coupled singlet–triplet qubits. Our approach, which relies on the physics underlying discrete time crystals, enhances the quality factor of spin-eigenstate swaps by up to an order of magnitude. Our results show how interactions and disorder in multi-qubit systems can stabilize non-trivial quantum operations and suggest potential uses for non-equilibrium quantum phenomena, like time crystals, in quantum information processing applications. Our results also confirm the long-predicted emergence of effective Ising interactions between exchange-coupled singlet–triplet qubits. 

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2. Entanglement-enhanced optomechanical sensing

   https://doi.org/10.1038/s41566-023-01178-0  

   Xia, Yi; Agrawal, Aman R.; Pluchar, Christian M.; Brady, Anthony J.; Liu, Zhen; Zhuang, Quntao; Wilson, Dalziel J.; Zhang, Zheshen (June 2023, Nature Photonics)

   Optomechanical systems have been exploited in ultrasensitive measurements of force, acceleration and magnetic fields. The fundamental limits for optomechanical sensing have been extensively studied and now well understood—the intrinsic uncertainties of the bosonic optical and mechanical modes, together with backaction noise arising from interactions between the two, dictate the standard quantum limit. Advanced techniques based on non-classical probes, in situ ponderomotive squeezed light and backaction-evading measurements have been developed to overcome the standard quantum limit for individual optomechanical sensors. An alternative, conceptually simpler approach to enhance optomechanical sensing rests on joint measurements taken by multiple sensors. In this configuration, a pathway to overcome the fundamental limits in joint measurements has not been explored. Here we demonstrate that joint force measurements taken with entangled probes on multiple optomechanical sensors can improve the bandwidth in the thermal-noise-dominant regime or the sensitivity in the shot-noise-dominant regime. Moreover, we quantify the overall performance of entangled probes with the sensitivity–bandwidth product and observe a 25% increase compared with that of classical probes. The demonstrated entanglement-enhanced optomechanical sensors would enable new capabilities for inertial navigation, acoustic imaging and searches for new physics. 

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3. QKD-Enhanced Cybersecurity Protocols

   https://doi.org/10.1109/JPHOT.2021.3069510  

   Djordjevic, Ivan B. (April 2021, IEEE Photonics Journal)

   null (Ed.)
4. Diffusiophoresis-enhanced Turing patterns

   https://doi.org/10.1126/sciadv.adj2457  

   Alessio, Benjamin M.; Gupta, Ankur (November 2023, Science Advances)

   Turing patterns are fundamental in biophysics, emerging from short-range activation and long-range inhibition processes. However, their paradigm is based on diffusive transport processes that yield patterns with shallower gradients than those observed in nature. A complete physical description of this discrepancy remains unknown. We propose a solution to this phenomenon by investigating the role of diffusiophoresis, which is the propulsion of colloids by a chemical gradient, in Turing patterns. Diffusiophoresis enables robust patterning of colloidal particles with substantially finer length scales than the accompanying chemical Turing patterns. A scaling analysis and a comparison to recent experiments indicate that chromatophores, ubiquitous in biological pattern formation, are likely diffusiophoretic and the colloidal Péclet number controls the pattern enhancement. This discovery suggests that important features of biological pattern formation can be explained with a universal mechanism that is quantified straightforwardly from the fundamental physics of colloids. 

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5. Plasmon-Enhanced Expansion Microscopy

   https://doi.org/10.1021/acs.nanolett.3c01256  

   Rathi, Priya; Gupta, Prashant; Debnath, Avishek; Baldi, Harsh; Wang, Yixuan; Gupta, Rohit; Raman, Baranidharan; Singamaneni, Srikanth (June 2023, Nano Letters)