arXiv subjects

Yujia Yuan

Publications and source records attributed to Yujia Yuan.

4 recordsLinked to original sources

arXiv2026

VisTacAlign: Co-Training Dexterous Policies on Tactile Human and Robot Demonstrations

Human demonstrations are a cheap source of data for dexterous manipulation, but co-training a robot policy on them requires closing the human--robot gap in every modality the policy consumes. We present VisTacAlign, a framework for co-training 3D-visual-tactile dexterous policies on human and robot demonstrations. Glove-tracked human hand motion is retargeted to a 17-DoF tactile robot hand with a one-time fingertip correction. The human hand is then erased from both stereo views and replaced by a posed robot-hand mesh painted with pixels from robot recordings, and a real-time stereo foundation model is re-run on the composite, so the human point clouds carry the same stereo errors and visibility as the robot ones. Finally, a capacitive tactile glove is aligned to the robot's fingertip sensors in its signal space, giving one interpretable per-finger force representation. A diffusion transformer consumes point-cloud, proprioceptive, and per-finger tactile tokens. On three real-world tasks requiring precise force -- Lego assembly, plucking strawberries of varying size, and activating and lifting a power drill -- adding aligned human demonstrations to existing robot data improves over robot-only policies, and ablations show that both tactile input and visual alignment are necessary. Project page: https://vis-tac-align.github.io

cs.RO↗

arXiv2026

Interfacial Engineering Enabled High-Resolution Stretchable Metal-Level Conductive Lines and Transparent Conductor

As stretchable electronics advance toward higher integration density and finer feature sizes, stretchable conductors, which serve as the architectural backbone of these electronics, must be scaled down accordingly. However, achieving both high stretchability and high electrical conductivity at high resolution remains a challenge using existing conductive materials. Here, through material design and interfacial engineering, we develop a thiol-functionalized conducting polymer/gold hybrid stack that can be patterned down to 4 micrometer linewidths using standard photolithography, while maintaining high stretchability, metal-like conductivity (>40,000 S/cm), and environmental stability. Leveraging this capability, we demonstrate grid-based stretchable transparent electrodes that surpass the figure-of-merit of indium tin oxide, as well as a 1000-pixel-per-inch image interconnected with stretchable lines. This work helps to broaden the scope of next-generation functional soft electronics, including e-skins and bioelectronics.

cond-mat.mtrl-sci↗

arXiv2026

A monolithic fabrication platform for intrinsically stretchable polymer transistors and complementary circuits

Soft, stretchable organic field-effect transistors (OFETs) can provide powerful on-skin signal conditioning, but current fabrication methods are often material-specific: each new polymer semiconductor (PSC) requires a tailored process. The challenge is even greater for complementary OFET circuits, where two PSCs must be patterned sequentially, which often leads to device degradation. Here, we introduce a universal, monolithic photolithography process that enables high-yield, high-resolution stretchable complementary OFETs and circuits. This approach is enabled by a process-design framework that includes (i) a direct, photopatternable, solvent-resistant, crosslinked dielectric/semiconductor interface, (ii) broadly applicable crosslinked PSC blends that preserve high mobility, and (iii) a patterning strategy that provides simultaneous etch masking and encapsulation. Using this platform, we achieve record integration density for stretchable OTFTs (55,000 cm^-2), channel lengths down to 2 um, and low-voltage operation at 5 V. We demonstrate photopatterning across multiple PSC types and realize complementary circuits, including 3 kHz stretchable ring oscillators, the first to exceed 1 kHz and representing more than a 60-fold increase in stage switching speed over the state of the art. Finally, we demonstrate the first stretchable complementary OTFT neuron circuit, where the output frequency is modulated by the input current to mimic neuronal signal processing. This scalable approach can be readily extended to diverse high-performance stretchable materials, accelerating the development and manufacturing of skin-like electronics.

eess.SY↗

arXiv2025

Reversible tuning of nanowire quantum dot to atomic transitions

Quantum dots embedded in semiconductor photonic nanowires (NW-QDs) can deterministically produce single-photons and entangled photon pairs at high repetition rates. These photons can be efficiently coupled from the photonic nanowire into free space or optical fibers thanks to the sharp tip of the nanowire, which provides impedance matching. However, precise control of the NW-QD emission frequency in a way that is reversible, does not degrade the properties of the emitted photons, and can be used independently for individual NW-QDs on the same chip has so far remained a challenge. Resolving this issue is crucial for applications when interfacing the photons with quantum systems that require MHz to sub-GHz precision, such as atomic ensembles acting as memories in a quantum network. Here, we demonstrate a reversible tuning method that can tune the emission frequency of a NW-QD by more than 300 GHz with sub-GHz precision. We achieve this through gas condensation that is then partially reversed with localized laser ablation. This process finely adjusts stress applied to the quantum dots, thereby tuning their emission frequency. We validate the precision and stability of this method by tuning the frequency of the emitted single-photons across an atomic resonance to probe its absorption and dispersion. We observed up to 80\% absorption of the single-photons from NW-QD in hot caesium vapour at the D1-line resonances and a 75-fold decrease in group velocity associated with the hyperfine transitions of the D1-line ground states. We observed no discernible effects in the second-order autocorrelation function, lifetime, or linewidth of the NW-QD emission for up to 300 GHz of tuning and we saw minimal effects on the fine structure splitting of the NW-QD when tuning up to 100 GHz.

quant-ph↗