@article{12599,
  abstract     = {Mountains are the water towers of the world, supplying a substantial part of both natural and anthropogenic water demands1,2. They are highly sensitive and prone to climate change3,4, yet their importance and vulnerability have not been quantified at the global scale. Here we present a global water tower index (WTI), which ranks all water towers in terms of their water-supplying role and the downstream dependence of ecosystems and society. For each water tower, we assess its vulnerability related to water stress, governance, hydropolitical tension and future climatic and socio-economic changes. We conclude that the most important (highest WTI) water towers are also among the most vulnerable, and that climatic and socio-economic changes will affect them profoundly. This could negatively impact 1.9 billion people living in (0.3 billion) or directly downstream of (1.6 billion) mountainous areas. Immediate action is required to safeguard the future of the world’s most important and vulnerable water towers.},
  author       = {Immerzeel, W. W. and Lutz, A. F. and Andrade, M. and Bahl, A. and Biemans, H. and Bolch, T. and Hyde, S. and Brumby, S. and Davies, B. J. and Elmore, A. C. and Emmer, A. and Feng, M. and Fernández, A. and Haritashya, U. and Kargel, J. S. and Koppes, M. and Kraaijenbrink, P. D. A. and Kulkarni, A. V. and Mayewski, P. A. and Nepal, S. and Pacheco, P. and Painter, T. H. and Pellicciotti, Francesca and Rajaram, H. and Rupper, S. and Sinisalo, A. and Shrestha, A. B. and Viviroli, D. and Wada, Y. and Xiao, C. and Yao, T. and Baillie, J. E. M.},
  issn         = {1476-4687},
  journal      = {Nature},
  number       = {7790},
  pages        = {364--369},
  publisher    = {Springer Nature},
  title        = {{Importance and vulnerability of the world’s water towers}},
  doi          = {10.1038/s41586-019-1822-y},
  volume       = {577},
  year         = {2020},
}

@article{12939,
  abstract     = {Linear tetrapyrroles, called phyllobilins, are obtained as major catabolites upon chlorophyll degradation. Primarily, colorless phylloleucobilins featuring four deconjugated pyrrole units were identified. Their yellow counterparts, phylloxanthobilins, were discovered more recently. Although the two catabolites differ only by one double bond, physicochemical properties are very distinct. Moreover, the presence of the double bond seems to enhance physiologically relevant bioactivities: in contrast to phylloleucobilin, we identified a potent anti-proliferative activity for a phylloxanthobilin, and show that this natural product induces apoptotic cell death and a cell cycle arrest in cancer cells. Interestingly, upon modifying inactive phylloleucobilin by esterification, an anti-proliferative activity can be observed that increases with the chain lengths of the alkyl esters. We provide first evidence for anti-cancer activity of phyllobilins, report a novel plant source for a phylloxanthobilin, and by using paper spray MS, show that these bioactive yellow chlorophyll catabolites are more prevalent in Nature than previously assumed.},
  author       = {Karg, Cornelia A. and Wang, Pengyu and Kluibenschedl, Florian and Müller, Thomas and Allmendinger, Lars and Vollmar, Angelika M. and Moser, Simone},
  issn         = {1434-193X},
  journal      = {European Journal of Organic Chemistry},
  keywords     = {Organic Chemistry, Physical and Theoretical Chemistry},
  number       = {29},
  pages        = {4499--4509},
  publisher    = {Wiley},
  title        = {{Phylloxanthobilins are abundant linear tetrapyrroles from chlorophyll breakdown with activities against cancer cells}},
  doi          = {10.1002/ejoc.202000692},
  volume       = {2020},
  year         = {2020},
}

@article{12940,
  abstract     = {Desorption electrospray ionization (DESI), easy ambient sonic-spray ionization (EASI) and low-temperature plasma (LTP) ionization are powerful ambient ionization techniques for mass spectrometry. However, every single method has its limitation in terms of polarity and molecular weight of analyte molecules. After the miniaturization of every possible component of the different ion sources, we finally were able to embed two emitters and an ion transfer tubing into a small, hand-held device. The pen-like interface is connected to the mass spectrometer and a separate control unit via a bundle of flexible tubing and cables. The novel device allows the user to ionize an extended range of chemicals by simple switching between DESI, voltage-free EASI, or LTP ionization as well as to freely move the interface over a surface of interest. A mini camera, which is mounted on the tip of the pen, magnifies the desorption area and enables a simple positioning of the pen. The interface was successfully tested using different types of chemicals, pharmaceuticals, and real life samples. Moreover, the combination of optical data from the camera module and chemical data obtained by mass analysis facilitates a novel type of imaging mass spectrometry, which we name “interactive mass spectrometry imaging (IMSI)”.},
  author       = {Meisenbichler, Christina and Kluibenschedl, Florian and Müller, Thomas},
  issn         = {0003-2700},
  journal      = {Analytical Chemistry},
  keywords     = {Analytical Chemistry},
  number       = {21},
  pages        = {14314--14318},
  publisher    = {American Chemical Society},
  title        = {{A 3-in-1 hand-held ambient mass spectrometry interface for identification and 2D localization of chemicals on surfaces}},
  doi          = {10.1021/acs.analchem.0c02615},
  volume       = {92},
  year         = {2020},
}

@misc{13056,
  abstract     = {This datasets comprises all data shown in plots of the submitted article "Converting microwave and telecom photons with a silicon photonic nanomechanical interface". Additional raw data are available from the corresponding author on reasonable request.},
  author       = {Arnold, Georg M and Wulf, Matthias and Barzanjeh, Shabir and Redchenko, Elena and Rueda Sanchez, Alfredo R and Hease, William J and Hassani, Farid and Fink, Johannes M},
  publisher    = {Zenodo},
  title        = {{Converting microwave and telecom photons with a silicon photonic nanomechanical interface}},
  doi          = {10.5281/ZENODO.3961561},
  year         = {2020},
}

@misc{13060,
  abstract     = {Coinfections with multiple pathogens can result in complex within-host dynamics affecting virulence and transmission. Whilst multiple infections are intensively studied in solitary hosts, it is so far unresolved how social host interactions interfere with pathogen competition, and if this depends on coinfection diversity. We studied how the collective disease defenses of ants – their social immunity ­– influence pathogen competition in coinfections of same or different fungal pathogen species. Social immunity reduced virulence for all pathogen combinations, but interfered with spore production only in different-species coinfections. Here, it decreased overall pathogen sporulation success, whilst simultaneously increasing co-sporulation on individual cadavers and maintaining a higher pathogen diversity at the community-level. Mathematical modeling revealed that host sanitary care alone can modulate competitive outcomes between pathogens, giving advantage to fast-germinating, thus less grooming-sensitive ones. Host social interactions can hence modulate infection dynamics in coinfected group members, thereby altering pathogen communities at the host- and population-level.},
  author       = {Milutinovic, Barbara and Stock, Miriam and Grasse, Anna V and Naderlinger, Elisabeth and Hilbe, Christian and Cremer, Sylvia},
  publisher    = {Dryad},
  title        = {{Social immunity modulates competition between coinfecting pathogens}},
  doi          = {10.5061/DRYAD.CRJDFN318},
  year         = {2020},
}

@misc{13065,
  abstract     = {Domestication is a human-induced selection process that imprints the genomes of domesticated populations over a short evolutionary time scale, and that occurs in a given demographic context. Reconstructing historical gene flow, effective population size changes and their timing is therefore of fundamental interest to understand how plant demography and human selection jointly shape genomic divergence during domestication. Yet, the comparison under a single statistical framework of independent domestication histories across different crop species has been little evaluated so far. Thus, it is unclear whether domestication leads to convergent demographic changes that similarly affect crop genomes. To address this question, we used existing and new transcriptome data on three crop species of Solanaceae (eggplant, pepper and tomato), together with their close wild relatives. We fitted twelve demographic models of increasing complexity on the unfolded joint allele frequency spectrum for each wild/crop pair, and we found evidence for both shared and species-specific demographic processes between species. A convergent history of domestication with gene-flow was inferred for all three species, along with evidence of strong reduction in the effective population size during the cultivation stage of tomato and pepper. The absence of any reduction in size of the crop in eggplant stands out from the classical view of the domestication process; as does the existence of a “protracted period” of management before cultivation. Our results also suggest divergent management strategies of modern cultivars among species as their current demography substantially differs. Finally, the timing of domestication is species-specific and supported by the few historical records available.},
  author       = {Arnoux, Stephanie and Fraisse, Christelle and Sauvage, Christopher},
  publisher    = {Dryad},
  title        = {{VCF files of synonymous SNPs related to: Genomic inference of complex domestication histories in three Solanaceae species}},
  doi          = {10.5061/DRYAD.Q2BVQ83HD},
  year         = {2020},
}

@misc{13070,
  abstract     = {This dataset comprises all data shown in the figures of the submitted article "Surpassing the resistance quantum with a geometric superinductor". Additional raw data are available from the corresponding author on reasonable request.},
  author       = {Peruzzo, Matilda and Trioni, Andrea and Hassani, Farid and Zemlicka, Martin and Fink, Johannes M},
  publisher    = {Zenodo},
  title        = {{Surpassing the resistance quantum with a geometric superinductor}},
  doi          = {10.5281/ZENODO.4052882},
  year         = {2020},
}

@misc{13071,
  abstract     = {This dataset comprises all data shown in the plots of the main part of the submitted article "Bidirectional Electro-Optic Wavelength Conversion in the Quantum Ground State". Additional raw data are available from the corresponding author on reasonable request.},
  author       = {Hease, William J and Rueda Sanchez, Alfredo R and Sahu, Rishabh and Wulf, Matthias and Arnold, Georg M and Schwefel, Harald and Fink, Johannes M},
  publisher    = {Zenodo},
  title        = {{Bidirectional electro-optic wavelength conversion in the quantum ground state}},
  doi          = {10.5281/ZENODO.4266025},
  year         = {2020},
}

@misc{13073,
  abstract     = {The Mytilus complex of marine mussel species forms a mosaic of hybrid zones, found across temperate regions of the globe. This allows us to study "replicated" instances of secondary contact between closely-related species. Previous work on this complex has shown that local introgression is both widespread and highly heterogeneous, and has identified SNPs that are outliers of differentiation between lineages. Here, we developed an ancestry-informative panel of such SNPs. We then compared their frequencies in newly-sampled populations, including samples from within the hybrid zones, and parental populations at different distances from the contact. Results show that close to the hybrid zones, some outlier loci are near to fixation for the heterospecific allele, suggesting enhanced local introgression, or the local sweep of a shared ancestral allele. Conversely, genomic cline analyses, treating local parental populations as the reference, reveal a globally high concordance among loci, albeit with a few signals of asymmetric introgression. Enhanced local introgression at specific loci is consistent with the early transfer of adaptive variants after contact, possibly including asymmetric bi-stable variants (Dobzhansky-Muller incompatibilities), or haplotypes loaded with fewer deleterious mutations. Having escaped one barrier, however, these variants can be trapped or delayed at the next barrier, confining the introgression locally. These results shed light on the decay of species barriers during phases of contact.},
  author       = {Simon, Alexis and Fraisse, Christelle and El Ayari, Tahani and Liautard-Haag, Cathy and Strelkov, Petr and Welch, John and Bierne, Nicolas},
  publisher    = {Dryad},
  title        = {{How do species barriers decay? concordance and local introgression in mosaic hybrid zones of mussels}},
  doi          = {10.5061/DRYAD.R4XGXD29N},
  year         = {2020},
}

@article{13341,
  abstract     = {Scanning nanoscale superconducting quantum interference devices (nanoSQUIDs)
are of growing interest for highly sensitive quantitative imaging of magnetic,
spintronic, and transport properties of low-dimensional systems. Utilizing
specifically designed grooved quartz capillaries pulled into a sharp pipette,
we have fabricated the smallest SQUID-on-tip (SOT) devices with effective
diameters down to 39 nm. Integration of a resistive shunt in close proximity to
the pipette apex combined with self-aligned deposition of In and Sn, have
resulted in SOT with a flux noise of 42 n$\Phi_0$Hz$^{-1/2}$, yielding a record
low spin noise of 0.29 $\mu_B$Hz$^{-1/2}$. In addition, the new SOTs function
at sub-Kelvin temperatures and in high magnetic fields of over 2.5 T.
Integrating the SOTs into a scanning probe microscope allowed us to image the
stray field of a single Fe$_3$O$_4$ nanocube at 300 mK. Our results show that
the easy magnetization axis direction undergoes a transition from the (111)
direction at room temperature to an in-plane orientation, which could be
attributed to the Verwey phase transition in Fe$_3$O$_4$.},
  author       = {Anahory, Y. and Naren, H. R. and Lachman, E. O. and Sinai, S. Buhbut and Uri, A. and Embon, L. and Yaakobi, E. and Myasoedov, Y. and Huber, M. E. and Klajn, Rafal and Zeldov, E.},
  issn         = {2040-3372},
  journal      = {Nanoscale},
  number       = {5},
  pages        = {3174--3182},
  publisher    = {Royal Society of Chemistry},
  title        = {{SQUID-on-tip with single-electron spin sensitivity for high-field and ultra-low temperature nanomagnetic imaging}},
  doi          = {10.1039/C9NR08578E},
  volume       = {12},
  year         = {2020},
}

@article{21083,
  abstract     = {Helically folded aromatic oligoamide foldamers have a size and geometrical parameters very distinct from those of α‐helices and are not obvious candidates for α‐helix mimicry. Nevertheless, they offer multiple sites for attaching side chains. It was found that some arrays of side chains at the surface of an aromatic helix make it possible to mimic extended α‐helical surfaces. Synthetic methods were developed to produce quinoline monomers suitably functionalized for solid phase synthesis. A dodecamer was prepared. Its crystal structure validated the initial design and showed helix bundling involving the α‐helix‐like interface. These results open up new uses of aromatic helices to recognize protein surfaces and to program helix bundling in water.},
  author       = {Zwillinger, Márton and Reddy, Post Sai and Wicher, Barbara and Mandal, Pradeep K and Csékei, Márton and Fischer, Lucile and Kotschy, András and Huc, Ivan},
  issn         = {1521-3765},
  journal      = {Chemistry – A European Journal},
  number       = {72},
  pages        = {17366--17370},
  publisher    = {Wiley},
  title        = {{Aromatic foldamer helices as α‐helix extended surface mimetics}},
  doi          = {10.1002/chem.202004064},
  volume       = {26},
  year         = {2020},
}

@article{21084,
  abstract     = {Self-assembly is a powerful method to obtain large discrete functional molecular architectures. When using a single building block, self-assembly generally yields symmetrical objects in which all the subunits relate similarly to their neighbours. Here we report the discovery of a family of self-constructing cyclic macromolecules with stable folded conformations of low symmetry, which include some with a prime number (13, 17 and 23) of units, despite being formed from a single component. The formation of these objects amounts to the production of polymers with a perfectly uniform length. Design rules for the spontaneous emergence of such macromolecules include endowing monomers with a strong potential for non-covalent interactions that remain frustrated in competing entropically favoured yet conformationally restrained smaller cycles. The process can also be templated by a guest molecule that itself has an asymmetrical structure, which paves the way to molecular imprinting techniques at the level of single polymer chains.},
  author       = {Pappas, Charalampos G. and Mandal, Pradeep K and Liu, Bin and Kauffmann, Brice and Miao, Xiaoming and Komáromy, Dávid and Hoffmann, Waldemar and Manz, Christian and Chang, Rayoon and Liu, Kai and Pagel, Kevin and Huc, Ivan and Otto, Sijbren},
  issn         = {1755-4349},
  journal      = {Nature Chemistry},
  number       = {12},
  pages        = {1180--1186},
  publisher    = {Springer Nature},
  title        = {{Emergence of low-symmetry foldamers from single monomers}},
  doi          = {10.1038/s41557-020-00565-2},
  volume       = {12},
  year         = {2020},
}

@article{21085,
  abstract     = {Foldamers combining aliphatic and aromatic main-chain units often produce atypical structures that cannot easily be accessed from purely aromatic or aliphatic sequences. We report solid-state evidence that sequences comprising α-amino acids and quinoline-based monomers adopt conformations that combine the folding propensities of both components. Foldamers 2 and 3 having an XQQ repeat motif (X=α-amino acid, Q=quinoline) were synthesized. Crystals of 2 (X=Phe, Q with an anionic side chain) obtained from water revealed an aromatic helix where amide groups belonging to the α-amino acids created a hydrogen-bond array typical of peptidic helices. Crystals of 3 (X=Ser, Q with a lipophilic side chain) obtained from organic solvents revealed a helix-turn-helix structure in which α-amino acid side chains interfere with main-chain hydrogen bonding. High sequence-dependency of the conformation is typical of peptides but is shown here to include aromatic folding features.},
  author       = {Hu, Xiaobo and Mandal, Pradeep K and Kauffmann, Brice and Huc, Ivan},
  issn         = {2192-6506},
  journal      = {ChemPlusChem},
  number       = {7},
  pages        = {1580--1586},
  publisher    = {Wiley},
  title        = {{Hybrid sequences that express both aromatic amide and α‐peptidic folding features}},
  doi          = {10.1002/cplu.202000416},
  volume       = {85},
  year         = {2020},
}

@article{21525,
  abstract     = {We present a novel design for an ultracompact, passive light source capable of generating ultraviolet and X-ray radiation, based on the interaction of free electrons with the magnetic near-field of a ferromagnet. Our design is motivated by recent advances in the fabrication of nanostructures, which allow the confinement of large magnetic fields at the surface of ferromagnetic nanogratings. Using ab initio simulations and a complementary analytical theory, we show that highly directional, tunable, monochromatic radiation at high frequencies could be produced from relatively low-energy electrons within a tabletop design. The output frequency is tunable in the extreme ultraviolet to hard X-ray range via electron kinetic energies from 1 keV to 5 MeV and nanograting periods from 1 μm to 5 nm. The proposed radiation source can achieve the tunability and monochromaticity of current free-electron-driven sources (free-electron lasers, synchrotrons, and laser-driven undulators), yet with a significantly reduced scale, cost, and complexity. Our design could help realize the next generation of tabletop or on-chip X-ray sources.},
  author       = {Fisher, Sophie and Roques-Carmes, Charles and Rivera, Nicholas and Wong, Liang Jie and Kaminer, Ido and Soljačić, Marin},
  issn         = {2330-4022},
  journal      = {ACS Photonics},
  keywords     = {X-ray sources, free electrons, nanostructure, undulator, synchrotron, free-electron laser},
  number       = {5},
  pages        = {1096--1103},
  publisher    = {American Chemical Society },
  title        = {{Monochromatic X-ray source based on scattering from a magnetic nanoundulator}},
  doi          = {10.1021/acsphotonics.0c00121},
  volume       = {7},
  year         = {2020},
}

@article{21539,
  abstract     = {The inability of conventional electronic architectures to efficiently solve large combinatorial problems motivates the development of novel computational hardware. There has been much effort toward developing application-specific hardware across many different fields of engineering, such as integrated circuits, memristors, and photonics. However, unleashing the potential of such architectures requires the development of algorithms which optimally exploit their fundamental properties. Here, we present the Photonic Recurrent Ising Sampler (PRIS), a heuristic method tailored for parallel architectures allowing fast and efficient sampling from distributions of arbitrary Ising problems. Since the PRIS relies on vector-to-fixed matrix multiplications, we suggest the implementation of the PRIS in photonic parallel networks, which realize these operations at an unprecedented speed. The PRIS provides sample solutions to the ground state of Ising models, by converging in probability to their associated Gibbs distribution. The PRIS also relies on intrinsic dynamic noise and eigenvalue dropout to find ground states more efficiently. Our work suggests speedups in heuristic methods via photonic implementations of the PRIS.},
  author       = {Roques-Carmes, Charles and Shen, Yichen and Zanoci, Cristian and Prabhu, Mihika and Atieh, Fadi and Jing, Li and Dubček, Tena and Mao, Chenkai and Johnson, Miles R. and Čeperić, Vladimir and Joannopoulos, John D. and Englund, Dirk and Soljačić, Marin},
  issn         = {2041-1723},
  journal      = {Nature Communications},
  publisher    = {Springer Nature},
  title        = {{Heuristic recurrent algorithms for photonic Ising machines}},
  doi          = {10.1038/s41467-019-14096-z},
  volume       = {11},
  year         = {2020},
}

@article{21554,
  abstract     = {Recent progress in artificial intelligence is largely attributed to the rapid development of machine learning, especially in the algorithm and neural network models. However, it is the performance of the hardware, in particular the energy efficiency of a computing system that sets the fundamental limit of the capability of machine learning. Data-centric computing requires a revolution in hardware systems, since traditional digital computers based on transistors and the von Neumann architecture were not purposely designed for neuromorphic computing. A hardware platform based on emerging devices and new architecture is the hope for future computing with dramatically improved throughput and energy efficiency. Building such a system, nevertheless, faces a number of challenges, ranging from materials selection, device optimization, circuit fabrication and system integration, to name a few. The aim of this Roadmap is to present a snapshot of emerging hardware technologies that are potentially beneficial for machine learning, providing the Nanotechnology readers with a perspective of challenges and opportunities in this burgeoning field.},
  author       = {Berggren, Karl and Xia, Qiangfei and Likharev, Konstantin K and Strukov, Dmitri B and Jiang, Hao and Mikolajick, Thomas and Querlioz, Damien and Salinga, Martin and Erickson, John R and Pi, Shuang and Xiong, Feng and Lin, Peng and Li, Can and Chen, Yu and Xiong, Shisheng and Hoskins, Brian D and Daniels, Matthew W and Madhavan, Advait and Liddle, James A and McClelland, Jabez J and Yang, Yuchao and Rupp, Jennifer and Nonnenmann, Stephen S and Cheng, Kwang-Ting and Gong, Nanbo and Lastras-Montaño, Miguel Angel and Talin, A Alec and Salleo, Alberto and Shastri, Bhavin J and de Lima, Thomas Ferreira and Prucnal, Paul and Tait, Alexander N and Shen, Yichen and Meng, Huaiyu and Roques-Carmes, Charles and Cheng, Zengguang and Bhaskaran, Harish and Jariwala, Deep and Wang, Han and Shainline, Jeffrey M and Segall, Kenneth and Yang, J Joshua and Roy, Kaushik and Datta, Suman and Raychowdhury, Arijit},
  issn         = {1361-6528},
  journal      = {Nanotechnology},
  number       = {1},
  publisher    = {IOP Publishing},
  title        = {{Roadmap on emerging hardware and technology for machine learning}},
  doi          = {10.1088/1361-6528/aba70f},
  volume       = {32},
  year         = {2020},
}

@inproceedings{21621,
  abstract     = {We show that nanophotonic structures enable the possibility of realizing lasers based on stimulated emission by free electrons. The associated threshold beam currents are in the nanoampere range, and could be realized in electron microscopes.},
  author       = {Rivera, Nicholas and Roques-Carmes, Charles and Kaminer, Ido and Soljačić, Marin},
  booktitle    = {Conference on Lasers and Electro-Optics},
  location     = {Washington, DC, United States},
  publisher    = {Optica Publishing Group},
  title        = {{Toward nanophotonic free-electron lasers}},
  doi          = {10.1364/cleo_qels.2020.fm2q.3},
  year         = {2020},
}

@article{21637,
  abstract     = {We demonstrate new axisymmetric inverse-design techniques that can solve problems radically different from traditional lenses, including reconfigurable lenses (that shift a multi-frequency focal spot in response to refractive-index changes) and widely separated multi-wavelength lenses (λ = 1 µm and 10 µm). We also present experimental validation for an axisymmetric inverse-designed monochrome lens in the near-infrared fabricated via two-photon polymerization. Axisymmetry allows fullwave Maxwell solvers to be scaled up to structures hundreds or even thousands of wavelengths in diameter before requiring domain-decomposition approximations, while multilayer topology optimization with ∼105 degrees of freedom can tackle challenging design problems even when restricted to axisymmetric structures.},
  author       = {Christiansen, Rasmus E. and Lin, Zin and Roques-Carmes, Charles and Salamin, Yannick and Kooi, Steven E. and Joannopoulos, John D. and Soljačić, Marin and Johnson, Steven G.},
  issn         = {1094-4087},
  journal      = {Optics Express},
  number       = {23},
  pages        = {33854--33868},
  publisher    = {Optica Publishing Group},
  title        = {{Fullwave Maxwell inverse design of axisymmetric, tunable, and multi-scale multi-wavelength metalenses}},
  doi          = {10.1364/oe.403192},
  volume       = {28},
  year         = {2020},
}

@article{21640,
  abstract     = {Conventional computing architectures have no known efficient algorithms for combinatorial optimization tasks such
as the Ising problem, which requires finding the ground state spin configuration of an arbitrary Ising graph. Physical
Ising machines have recently been developed as an alternative to conventional exact and heuristic solvers; however,
these machines typically suffer from decreased ground state convergence probability or universality for high edge-
density graphs or arbitrary graph weights, respectively. We experimentally demonstrate a proof-of-principle integrated
nanophotonic recurrent Ising sampler (INPRIS), using a hybrid scheme combining electronics and silicon-on-insulator
photonics, that is capable of converging to the ground state of various four-spin graphs with high probability. The
INPRIS results indicate that noise may be used as a resource to speed up the ground state search and to explore larger
regions of the phase space, thus allowing one to probe noise-dependent physical observables. Since the recurrent pho-
tonic transformation that our machine imparts is a fixed function of the graph problem and therefore compatible with
optoelectronic architectures that support GHz clock rates (such as passive or non-volatile photonic circuits that do not
require reprogramming at each iteration), this work suggests the potential for future systems that could achieve orders-
of-magnitude speedups in exploring the solution space of combinatorially hard problems. },
  author       = {Prabhu, Mihika and Roques-Carmes, Charles and Shen, Yichen and Harris, Nicholas and Jing, Li and Carolan, Jacques and Hamerly, Ryan and Baehr-Jones, Tom and Hochberg, Michael and Čeperić, Vladimir and Joannopoulos, John D. and Englund, Dirk R. and Soljačić, Marin},
  issn         = {2334-2536},
  journal      = {Optica},
  number       = {5},
  pages        = {551--558},
  publisher    = {Optica Publishing Group},
  title        = {{Accelerating recurrent Ising machines in photonic integrated circuits}},
  doi          = {10.1364/optica.386613},
  volume       = {7},
  year         = {2020},
}

@article{21642,
  abstract     = {By codesigning a metaoptical front end in conjunction with an image‐processing back end, we demonstrate noise sensitivity and compactness substantially superior to either an optics‐only or a computation‐only approach, illustrated by two examples: subwavelength imaging and reconstruction of the full polarization coherence matrices of multiple light sources. Our end‐to‐end inverse designs couple the solution of the full Maxwell equations—exploiting all aspects of wave physics arising in subwavelength scatterers—with inverse‐scattering algorithms in a single large‐scale optimization involving  degrees of freedom. The resulting structures scatter light in a way that is radically different from either a conventional lens or a random microstructure, and suppress the noise sensitivity of the inverse‐scattering computation by several orders of magnitude. Incorporating the full wave physics is especially crucial for detecting spectral and polarization information that is discarded by geometric optics and scalar diffraction theory.},
  author       = {Lin, Zin and Roques-Carmes, Charles and Pestourie, Raphaël and Soljačić, Marin and Majumdar, Arka and Johnson, Steven G.},
  issn         = {2192-8614},
  journal      = {Nanophotonics},
  keywords     = {computational imaging, end-to-end photonic inverse design, inverse scattering, meta-optics, polarimetry},
  number       = {3},
  pages        = {1177--1187},
  publisher    = {Wiley},
  title        = {{End‐to‐end nanophotonic inverse design for imaging and polarimetry}},
  doi          = {10.1515/nanoph-2020-0579},
  volume       = {10},
  year         = {2020},
}

