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Conversion between signals in the microwave and optical domains is of great interest both for classical telecommunication and for connecting future superconducting quantum computers into a global quantum network. For quantum applications, the conversion has to be efficient, as well as operate in a regime of minimal added classical noise. While efficient conversion has been demonstrated using mechanical transducers, they have so far all operated with a substantial thermal noise background. Here, we overcome this limitation and demonstrate coherent conversion between gigahertz microwave signals and the optical telecom band with a thermal background of less than one phonon. We use an integrated, on-chip electro-optomechanical device that couples surface acoustic waves driven by a resonant microwave signal to an optomechanical crystal featuring a 2.7 GHz mechanical mode. We initialize the mechanical mode in its quantum ground state, which allows us to perform the transduction process with minimal added thermal noise, while maintaining an optomechanical cooperativity >1, so that microwave photons mapped into the mechanical resonator are effectively upconverted to the optical domain. We further verify the preservation of the coherence of the microwave signal throughout the transduction process. Electro-optomechanical conversion between optical and microwave photons is achieved with minimal added noise by cooling the mechanical oscillator to its quantum ground state. This has potential for future coherence-preserving transduction.

Nanofabricated mechanical resonators are gaining significant momentum among potential quantum technologies due to their unique design freedom and independence from naturally occurring resonances. As their functionality is widely detached from material choice, they constitute ideal tools for transducers—intermediaries between different quantum systems—and as memory elements in conjunction with quantum communication and computing devices. Their capability to host ultra-long-lived phonon modes is particularity attractive for non-classical information storage, both for future quantum technologies and for fundamental tests of physics. Here, we demonstrate a Duan–Lukin–Cirac–Zoller-type mechanical quantum memory with an energy decay time of T 1  ≈ 2 ms, which is controlled through an optical interface engineered to natively operate at telecom wavelengths. We further investigate the coherence of the memory, equivalent to the dephasing T 2 * for qubits, which has a power-dependent value between 15 and 112 μs. This demonstration is enabled by an optical scheme to create a superposition state of 0 + 1 mechanical excitations, with an arbitrary ratio between the vacuum and single-phonon components. By exploiting the long-lived phonon modes in nanoscale mechanical resonators, a quantum memory that operates around the standard telecom wavelength of 1,550 nm is realized on a silicon platform.

Quantum teleportation, the faithful transfer of an unknown input state onto a remote quantum system1, is a key component in long-distance quantum communication protocols2 and distributed quantum computing3,4. At the same time, high-frequency nano-optomechanical systems5 hold great promise as nodes in a future quantum network6, operating on-chip at low-loss optical telecom wavelengths with long mechanical lifetimes. Recent demonstrations include entanglement between two resonators7, a quantum memory8 and microwave-to-optics transduction9–11. Despite these successes, quantum teleportation of an optical input state onto a long-lived optomechanical memory is an outstanding challenge. Here we demonstrate quantum teleportation of a polarization-encoded optical input state onto the joint state of a pair of nanomechanical resonators. Our protocol also allows to store and retrieve an arbitrary qubit state onto a dual-rail encoded optomechanical quantum memory. This work demonstrates the full functionality of a single quantum repeater node and presents a key milestone towards applications of optomechanical systems as quantum network nodes.Quantum teleportation of a photonic qubit into mechanical modes of two silicon photonic crystal nanobeams is demonstrated. It allows to store and retrieve an arbitrary qubit state onto a dual-rail encoded long-lived optomechanical quantum memory.

Nano- and micromechanical solid-state quantum devices have become a focus of attention. Reliably generating nonclassical states of their motion is of interest both for addressing fundamental questions about macroscopic quantum phenomena and for developing quantum technologies in the domains of sensing and transduction. We used quantum optical control techniques to conditionally generate single-phonon Fock states of a nanomechanical resonator. We performed a Hanbury Brown and Twiss–type experiment that verified the nonclassical nature of the phonon state without requiring full state reconstruction. Our result establishes purely optical quantum control of a mechanical oscillator at the single-phonon level.

Extracellular vesicles are cell-derived secretions that mediate tissue homeostasis and intercellular communication through their diverse cargos, including proteins. Distinct extracellular vesicle biogenesis pathways suggest specific association and co-enrichment of proteins sharing a biogenesis pathway, and non-association and co-depletion of proteins segregated into distinct pathways. Yet these associations elude conventional protein expression or co-expression measurements. Here, we propose and define pairwise protein co-enrichment relative to its overall expression to quantify whether a given protein is co-enriched or co-depleted with another protein. We measure co-enrichment, and differential co-enrichment between a stimulus and a reference condition, of up to 240 protein pairs in extracellular vesicles using antibody microarrays. We validate co-enrichment by modulating well-known extracellular vesicle biogenesis pathways, and find that differential co-enrichment measures expected changes between perturbed and reference conditions. Co-enrichment and differential co-enrichment in three model cell lines and parental and organotropic breast cancer progeny cell lines reveal both preserved and variable co-enrichment that may warrant further studies. Collectively, our result suggest that co-enrichment reflects cell physiology and extracellular biogenesis, is readily measurable, and could serve as quality control in extracellular vesicle biomanufacturing. Distinct extracellular vesicle biogenesis pathways suggest specific co-enrichment of proteins sharing a biogenesis pathway. Here, the authors design an approach to examine this co-enrichment and show that it reflects vesicle biogenesis.

Immunofluorescence analysis of individual extracellular vesicles (EVs) in common fluorescence microscopes is gaining popularity due to its accessibility and high fluorescence sensitivity; however, EV number and size are only measurable using fluorescent stains requiring extensive sample manipulations. Here we introduce highly sensitive label‐free EV size photometry (SP) based on interferometric scattering (iSCAT) imaging of immersed EVs immobilized on a glass coverslip. We implement SP on a common inverted epifluorescence microscope with LED illumination and a simple 50:50 beamsplitter, permitting seamless integration of SP with fluorescence imaging (SPFI). We present a high‐throughput SPFI workflow recording >10,000 EVs in 7 min over ten 88 × 88 µm2 fields of view, pre‐ and post‐incubation imaging to suppress background, along with automated image alignment, aberration correction, spot detection and EV sizing. We achieve an EV sizing range from 37 to ∼220 nm in diameter with a dual 440 and 740 nm SP illumination scheme, and suggest that this range can be extended by more advanced image analysis or additional hardware customization. We benchmark SP to flow cytometry using calibrated silica nanoparticles and demonstrate superior, label‐free sensitivity. We showcase SPFI's potential for EV analysis by experimentally distinguishing surface and volumetric EV dyes, observing the deformation of EVs adsorbed to a surface, and by uncovering distinct subpopulations in <100 nm‐in‐diameter EVs with fluorescently tagged membrane proteins.

Entanglement, an essential feature of quantum theory that allows for inseparable quantum correlations to be shared between distant parties, is a crucial resource for quantum networks 1 . Of particular importance is the ability to distribute entanglement between remote objects that can also serve as quantum memories. This has been previously realized using systems such as warm 2 , 3 and cold atomic vapours 4 , 5 , individual atoms 6 and ions 7 , 8 , and defects in solid-state systems 9 – 11 . Practical communication applications require a combination of several advantageous features, such as a particular operating wavelength, high bandwidth and long memory lifetimes. Here we introduce a purely micromachined solid-state platform in the form of chip-based optomechanical resonators made of nanostructured silicon beams. We create and demonstrate entanglement between two micromechanical oscillators across two chips that are separated by 20 centimetres . The entangled quantum state is distributed by an optical field at a designed wavelength near 1,550 nanometres. Therefore, our system can be directly incorporated in a realistic fibre-optic quantum network operating in the conventional optical telecommunication band. Our results are an important step towards the development of large-area quantum networks based on silicon photonics. Remote quantum entanglement is demonstrated in a micromachined solid-state system comprising two optomechanical oscillators across two chips physically separated by 20 cm and with an optical separation of around 70 m.

Conversion between signals in the microwave and optical domains is of great interest both for classical telecommunication, as well as for connecting future superconducting quantum computers into a global quantum network. For quantum applications, the conversion has to be both efficient, as well as operate in a regime of minimal added classical noise. While efficient conversion has been demonstrated using mechanical transducers, they have so far all operated with a substantial thermal noise background. Here, we overcome this limitation and demonstrate coherent conversion between GHz microwave signals and the optical telecom band with a thermal background of less than one phonon. We use an integrated, on-chip electro-opto-mechanical device that couples surface acoustic waves driven by a resonant microwave signal to an optomechanical crystal featuring a 2.7 GHz mechanical mode. We initialize the mechanical mode in its quantum groundstate, which allows us to perform the transduction process with minimal added thermal noise, while maintaining an optomechanical cooperativity >1, so that microwave photons mapped into the mechanical resonator are effectively upconverted to the optical domain. We further verify the preservation of the coherence of the microwave signal throughout the transduction process.

Quantum teleportation, the faithful transfer of an unknown input state onto a remote quantum system, is a key component in long distance quantum communication protocols and distributed quantum computing. At the same time, high frequency nano-optomechanical systems hold great promise as nodes in a future quantum network, operating on-chip at low-loss optical telecom wavelengths with long mechanical lifetimes. Recent demonstrations include entanglement between two resonators, a quantum memory and microwave to optics transduction. Despite these successes, quantum teleportation of an optical input state onto a long-lived optomechanical memory is an outstanding challenge. Here we demonstrate quantum teleportation of a polarization-encoded optical input state onto the joint state of a pair of nanomechanical resonators. Our protocol also allows for the first time to store and retrieve an arbitrary qubit state onto a dual-rail encoded optomechanical quantum memory. This work demonstrates the full functionality of a single quantum repeater node, and presents a key milestone towards applications of optomechanical systems as quantum network nodes.

Nanofabricated mechanical resonators are gaining significant momentum among potential quantum technologies due to their unique design freedom and independence from naturally occurring resonances. With their functionality being widely detached from material choice, they constitute ideal tools to be used as transducers, i.e. intermediaries between different quantum systems, and as memory elements in conjunction with quantum communication and computing devices. Their capability to host ultra-long lived phonon modes is particularity attractive for non-classical information storage, both for future quantum technologies as well as for fundamental tests of physics. Here we demonstrate such a mechanical quantum memory with an energy decay time of \\(T_12\\) ms, which is controlled through an optical interface engineered to natively operate at telecom wavelengths. We further investigate the coherence of the memory, equivalent to the dephasing \\(T_2^*\\) for qubits, which exhibits a power dependent value between 15 and 112 \\(\\)s. This demonstration is enabled by a novel optical scheme to create a superposition state of \\(0+1\\) mechanical excitations, with an arbitrary ratio between the vacuum and single phonon components.