About

Nicholas Boechler is a Professor in the Department of Mechanical and Aerospace Engineering and the Program in Materials Science and Engineering at UC San Diego. He received his B.S. in Aerospace Engineering from Georgia Tech, followed by an M.S. in Aerospace Engineering and a Ph.D. in Aeronautics from Caltech. After completing his doctoral studies, he worked as a Postdoctoral Associate at MIT from Fall 2011 to Spring 2013. Since joining the faculty in 2013, Professor Boechler has been recognized with prestigious awards including the Army Research Office and Air Force Office of Scientific Research Young Investigator Program awards, as well as the 2017 International Congress on Ultrasonics (ICU) Early Career Award.

Research topics

• Computer Science
• Materials science
• Composite material
• Nanotechnology
• Optoelectronics
• Mechanical engineering
• Physics
• Engineering
• Acoustics
• Optics
• Geometry
• Computer graphics (images)
• Telecommunications

Selected publications

• Three phases of odd robotic active matter

  arXiv (Cornell University) · 2026-03-10

  preprintOpen access

  Nonreciprocal interactions in active matter are known to generate exotic mechanical behaviors such as odd elasticity and odd viscosity. However, these phenomena have largely been studied in isolation, raising a fundamental question: Is there a single system that embodies these distinct regimes of odd matter and can transition between phases, establishing a unified phase diagram for nonreciprocal active matter? To address this, we introduce a tunable robotic active matter platform, the Magnetomechanically Augmented Spinning roBotic (MASBot) collective, in which particle-level control of chirality, activity, and pairwise interactions enables access to distinct phases of odd matter. By continuously increasing repulsive forces relative to attractive and transverse forces, we experimentally map a transition from an odd elastic crystal to an odd viscous liquid, and then to a chiral active gas. We find that this latter phase forms a non-space-filling, nonreciprocal active gas stabilized by long-range hydrodynamic attractive forces, whose statistical signatures are consistent with those of a two-dimensional self-gravitating point vortex gas. Within these phases, adjusting spinning frequency and introducing spatially patterned activity allows us to fine-tune odd mechanical responses and tailor power spectra. Further polar and rotational symmetry breaking at the particle scale leads to novel emergent states such as phase separation and collective translation. Together, our system provides a fundamental experimental testbed for nonequilibrium physics and establishes a blueprint for treating robotic swarms as programmable states of matter, enabling functions that range from resilient structures to adaptive swarm reconfiguration.

  PublisherDOI

• Three phases of odd robotic active matter

  arXiv (Cornell University) · 2026-03-10

  articleOpen access

  Nonreciprocal interactions in active matter are known to generate exotic mechanical behaviors such as odd elasticity and odd viscosity. However, these phenomena have largely been studied in isolation, raising a fundamental question: Is there a single system that embodies these distinct regimes of odd matter and can transition between phases, establishing a unified phase diagram for nonreciprocal active matter? To address this, we introduce a tunable robotic active matter platform, the Magnetomechanically Augmented Spinning roBotic (MASBot) collective, in which particle-level control of chirality, activity, and pairwise interactions enables access to distinct phases of odd matter. By continuously increasing repulsive forces relative to attractive and transverse forces, we experimentally map a transition from an odd elastic crystal to an odd viscous liquid, and then to a chiral active gas. We find that this latter phase forms a non-space-filling, nonreciprocal active gas stabilized by long-range hydrodynamic attractive forces, whose statistical signatures are consistent with those of a two-dimensional self-gravitating point vortex gas. Within these phases, adjusting spinning frequency and introducing spatially patterned activity allows us to fine-tune odd mechanical responses and tailor power spectra. Further polar and rotational symmetry breaking at the particle scale leads to novel emergent states such as phase separation and collective translation. Together, our system provides a fundamental experimental testbed for nonequilibrium physics and establishes a blueprint for treating robotic swarms as programmable states of matter, enabling functions that range from resilient structures to adaptive swarm reconfiguration.

  PublisherOA PDF

• Observation of mechanical kink control and generation via acoustic waves

  Nature Communications · 2026-02-06

  articleOpen accessSenior authorCorresponding

  Kinks are localized transitions between topologically distinct ground states and play a central role in systems from condensed matter to cosmology. While acoustic wave packets (here defined as small-amplitude mechanical waves, sometimes referred to as phonons) have been predicted to drive kink motion deterministically, experimental evidence has been elusive, with only stochastic motion from thermal phonons or quasi-static loading observed. This is largely due to the discrete nature of real materials, where the Peierls-Nabarro (PN) barrier hinders controlled phonon-kink interactions. Here, we report experimental observation of acoustic-wave-mediated control and generation of mechanical kinks in a topological metamaterial, which eliminates the PN barrier by supporting a zero-energy kink. We also computationally reveal the dynamics of acoustic wave packet interplay with highly discrete kinks, including long-duration motion and a continuous family of internal modes-features absent in conventional discrete nonlinear systems. Our results enable remote kink control, with potential applications in material stiffness tuning, shape morphing, locomotion, and robust signal transmission.

  PublisherDOI

• Single-particle edge state in a local-resonance-induced topological band gap

  Open MIND · 2026-03-05

  preprint

  Topological metamaterials promise unprecedented wave control. Here, we theoretically and numerically investigate a one-dimensional Su-Schrieffer-Heeger (SSH) inspired stiffness dimer modified with a local resonator, which imparts a frequency-dependent effective stiffness to the unit cell. We demonstrate a two-step mechanism to create a topological local-resonance-induced band gap (LRG): first, a conventional Bragg-type band gap (BrG) is made topologically non-trivial via band inversion at a Dirac point; second, by tuning a dimerization parameter, the character of this non-trivial BrG is switched to that of an LRG via an intermediate flat band state. This process preserves the non-trivial topology without requiring gap closure within the LRG. Crucially, we find that when the resulting topological edge state intersects a characteristic frequency of the LRG -- specifically, an attenuation singularity where the effective stiffness vanishes -- it achieves extreme localization of vibrational energy. This state is confined to a single particle at the boundary, resulting in an inverse participation ratio of exactly unity, the theoretical limit for localization in a discrete system. Further, we demonstrate that while random disorder scatters the frequency of this mode, introducing tuned boundaries stabilizes the single-particle mode over a broad parameter range. Our findings provide a clear pathway to designing ultra-localized, topologically protected states in low-frequency regimes.

  DOI

• Single-particle edge state in a local-resonance-induced topological band gap

  ArXiv.org · 2026-03-05

  articleOpen access

  Topological metamaterials promise unprecedented wave control. Here, we theoretically and numerically investigate a one-dimensional Su-Schrieffer-Heeger (SSH) inspired stiffness dimer modified with a local resonator, which imparts a frequency-dependent effective stiffness to the unit cell. We demonstrate a two-step mechanism to create a topological local-resonance-induced band gap (LRG): first, a conventional Bragg-type band gap (BrG) is made topologically non-trivial via band inversion at a Dirac point; second, by tuning a dimerization parameter, the character of this non-trivial BrG is switched to that of an LRG via an intermediate flat band state. This process preserves the non-trivial topology without requiring gap closure within the LRG. Crucially, we find that when the resulting topological edge state intersects a characteristic frequency of the LRG -- specifically, an attenuation singularity where the effective stiffness vanishes -- it achieves extreme localization of vibrational energy. This state is confined to a single particle at the boundary, resulting in an inverse participation ratio of exactly unity, the theoretical limit for localization in a discrete system. Further, we demonstrate that while random disorder scatters the frequency of this mode, introducing tuned boundaries stabilizes the single-particle mode over a broad parameter range. Our findings provide a clear pathway to designing ultra-localized, topologically protected states in low-frequency regimes.

  PublisherOA PDF

• Minimizing finite viscosity enhances relative kinetic energy absorption in bistable mechanical metamaterials but only with sufficiently fine discretization: A nonlinear dynamical size effect

  Journal of the Mechanics and Physics of Solids · 2025-03-13 · 2 citations

  articleSenior authorCorresponding
  PublisherDOI

• Computational inverse design of acoustoplasmonic metasurfaces

  Applied Physics Letters · 2025-06-23

  article

  Optical and acoustic metasurfaces are two-dimensional arrays of subwavelength elements that locally modulate or phase shift incident waves. Acoustoplasmonic metasurfaces combine the physics of light and sound, producing acoustic wavefronts in response to optical stimuli. Herein, we present a computational inverse acoustoplasmonic metasurface design algorithm for desired optically generated acoustic wave fields. We consider gold nanoparticles producing spherical acoustic waves in water, and the resulting acoustic wave propagation along the plane containing the nanoparticle array. We demonstrate how our algorithm can be used to design metasurfaces that can be used to achieve complex acoustic wave fields. This includes the design of a single metasurface that produces acoustic wave fields mimicking two different Morse code patterns upon stimulation with two orthogonal polarization states of light. This work provides a tool for the design of complex optically generated acoustic wavefronts, enabling functionality beyond what would be achievable with off-optical-resonance optoacoustic excitation.

  PublisherDOI

• Inverse design of two-dimensional architected materials with desired uniaxial polynomial nonlinear constitutive responses aided by stiffness normalization

  Materials & Design · 2025-09-11 · 1 citations

  articleOpen accessSenior author

  The design of specified nonlinear mechanical responses into a structure or material is a highly sought after capability, with significant potential impacts in areas such as wave tailoring in metamaterials, impact mitigation, soft robotics, and biomedicine. Here, we present a topology optimization approach to design two-dimensional structures for desired uniaxial polynomial nonlinear behavior, wherein we formulate the objective function to match nonlinear coefficient ratios, such that the linear stiffness is decoupled from the desired nonlinearity of the response. We suggest that such linear stiffness decoupling can help aid convergence for problems with fixed, but poorly matched, constituent materials and design volumes. This benefit can be understood by considering, if large absolute force values and stiffnesses are targeted, thicker structures with less open space generally result. Such high volume ratio structures reduce the kinematic freedom (available to, e.g. , long thin structures) which is needed for strong geometrically nonlinear responses. We show designs achieved using this approach that match a range of qualitatively different polynomial behaviors with high precision, which are of interest, in particular, within the domain of dynamical systems where nonlinear elasticity of relatively simple polynomial forms can confer greater analytical tractability. • We present a computational inverse design method for tailoring architected materials for high precision nonlinear, polynomial-described constitutive behavior. • A key enabling insight is the decoupling of the nonlinear response from the structural stiffness. • This approach enables the design and physical realization of materials that were previously difficult or impossible to design for. • This capability has potential applications in designing bulk materials for impact mitigation, nonlinear wave tailoring, soft robotics, and bio-interfaces.

  PublisherDOI

• Customizable wave tailoring nonlinear materials enabled by bilevel inverse design

  Nature Communications · 2025-04-10 · 4 citations

  articleOpen accessSenior author

  Passive wave transformation via nonlinearity is ubiquitous in settings from acoustics to optics and electromagnetics. It is well known that different nonlinearities yield different effects on propagating signals, which raises the question of "what precise nonlinearity is the best for a given wave tailoring application?" In this work, considering a one-dimensional spring-mass chain connected by polynomial springs (a variant of the Fermi-Pasta-Ulam-Tsingou system), we introduce a bilevel inverse design method which couples the shape optimization of structures for tailored constitutive responses with reduced-order nonlinear dynamical inverse design. We apply it to two qualitatively distinct problems-minimization of peak transmitted kinetic energy from impact, and pulse shape transformation-demonstrating our method's breadth of applicability. For the impact problem, we obtain two fundamental insights. First, small differences in nonlinearity can drastically change the dynamic response of the system, from severely under- to outperforming a comparative linear system. Second, the oft-used strategy of impact mitigation via "energy locking" bistability can be significantly outperformed by our optimal nonlinearity. We validate this case with impact experiments and find excellent agreement. This study establishes a framework for broader passive nonlinear mechanical wave tailoring material design, with applications to computing, signal processing, shock mitigation, and autonomous materials.

  PublisherOA PDFDOI

• Toward comfortable mosquito-proof clothing: repellent- and insecticide-free fabrics that block bites across three disease-transmitting mosquito genera

  Journal of Medical Entomology · 2025-10-27

  articleOpen access

  Mosquito-borne disease and nuisance biting from mosquitoes have severe health and economic consequences. Conventional fabrics are typically not effective at providing protection against mosquito bites, and fabrics treated with repellents and/or insecticides are limited by rising insecticide resistance, risk of significant dermatologic and neurologic side effects, and decreased efficacy with washing and time. The goal of this study was to identify commercially available, repellent/insecticide-free, comfortable fabrics that block bites from three genera of mosquitoes that are known to transmit dangerous infectious diseases with widespread distribution: Aedes, Anopheles, and Culex. To do this, we evaluated fabrics from Ripstop By the Roll LLC in a step-wise series of mouse blood-feeding and behavioral bioassays. Out of 88 fabrics, 53 were found to be blood-feed-proof. These fabrics were more likely to have a higher areal weight density (AWD) and a polyurethane coating than blood-feed-susceptible fabrics. Of the six most comfortable fabrics by subjective hand-feel testing, five were definitively bite-proof during behavioral bioassays. These five fabrics varied substantially in AWD, thickness, finish/coating, and fiber pattern. None of them had a polyurethane coating. Three of them were breathable, making them appropriate for active-wear clothing. Overall, the bite-proof fabrics identified in this study have the potential to significantly reduce mosquito biting and the transmission of mosquito-borne diseases.

  PublisherOA PDFDOI

Recent grants

• Micro- to Nanoscale Granular Contact Dynamics and Nonlinear Granular-Elastic Metamaterials

  NSF · $297k · 2013–2017

• Collaborative Research: Dynamics and Propagation of Surface Instabilities in Soft Materials

  NSF · $111k · 2018–2019

• Collaborative Research: Dynamics and Propagation of Surface Instabilities in Soft Materials

  NSF · $279k · 2015–2019

Frequent coauthors

• Maroun Abi Ghanem

  Institut Lumière Matière

  39 shared

• Florian Allein

  Centre National de la Recherche Scientifique

  34 shared

• G. Theocharis

  Centre National de la Recherche Scientifique

  28 shared

• Amey Khanolkar

  Idaho National Laboratory

  21 shared

• A. A. Maznev

  18 shared

• Samuel P. Wallen

  Applied Research Laboratories, The University of Texas at Austin

  18 shared

• Chiara Daraio

  Meta (United States)

  15 shared

• Brianna C. Macnider

  13 shared

Labs

• Boechler Research GroupPI

Education

• B.S.

  Georgia Institute of Technology

  2007

• M.S.

  California Institute of Technology

  2008

• Ph.D.

  California Institute of Technology

  2011

Awards & honors

• Young Investigator Program awards from the Army Research Off…
• Young Investigator Program awards from the Air Force Office…