Rajan Plumley

All Publications

• An agentic artificially intelligent X-ray scientist NATURE MACHINE INTELLIGENCE Chen, Z., Petsch, A. N., Israelski, A. J., Plumley, R., Shen, L., Wang, C., Peng, C., Bansil, A., Ni, Y., Chowdhury, S., Li, M., Thayer, J. B., Thampy, V., Turner, J. J. 2026

  View details for DOI 10.1038/s42256-026-01261-5

  View details for Web of Science ID 001808431400001

• Measurement of turbulent velocity and bounds for thermal diffusivity in laser shock compressed foams by x-ray photon correlation spectroscopy. Physical review. E Heaton, C., Yin, H., Khaghani, D., Lee, H. J., Poole, H., Blackman, E., Boiadjieva, N., Chen, X. M., Crepisson, C., Collins, G. W., Descamps, A., Gleason, A. E., Gutt, C., Petsch, A. N., Randolph, L., Nelson, S., McGehee, P., Plumley, R., Spindloe, C., Stevens, T., Stuart, C., Turner, J. J., Aluie, H., Shang, J. K., Gregori, G. 2025; 112 (4-2): 045218

  Abstract

  Experimental benchmarking of transport coefficients under extreme conditions is required for validation of differing theoretical models. To date, measurement of transport properties of dynamically compressed samples remains a challenge with only a limited number of studies able to quantify transport in high pressure and temperature matter. x-ray photon correlation spectroscopy utilizes coherent x-ray sources to measure time correlations of density fluctuations, thus providing measurements of length and timescale-dependent transport properties. Here, we present a first-of-a-kind experiment to conduct x-ray photon correlation spectroscopy in laser shock compression experiments. We report measurement of the turbulent velocity in the wake of a laser driven supersonic shock and place an upper bound on thermal diffusivity in a solid density plasma on nanosecond timescales.

  View details for DOI 10.1103/lff9-f3c1

  View details for PubMedID 41250372

• femto-PIXAR: a self-supervised neural network method for reconstructing femtosecond X-ray free electron laser pulses OPTICS EXPRESS Goetzke, G., Plumley, R., Hartmann, G., Maxwell, T., Decker, F., Lutman, A., Dunne, M., Ratner, D., Turner, J. 2025; 33 (15): 31235-31243

  Abstract

  X-ray free electron lasers (X-FELs) produce ultrafast pulses in a wide range of lasing configurations, supporting a wide variety of scientific applications, including structural biology, materials science, and atomic and molecular physics. Shot-by-shot characterization of the X-FEL pulses is crucial for the analysis of experiments as well as for tuning the X-FEL performance. However, for the weak pulses found in advanced configurations, e.g., those needed for monochromatic, two-pulse studies of quantum materials, there is no current method for reliably resolving pulse profiles. Here, we show that an interpretable neural network (NN) model can reconstruct the individual pulse power profiles for sub-picosecond pulse separation without the need for simulations. Using experimental data from low-signal X-FEL pulse pairs, we demonstrate a NN can learn the pulse characteristics on a shot-by-shot basis when conventional methods fail. This new method enables the characterization of weak pulses-a condition expected to dominate future experimental configurations such as at the Linac Coherent Light Source-II-and opens the door to a wide range of new experiments.

  View details for DOI 10.1364/OE.562798

  View details for Web of Science ID 001542177100006

  View details for PubMedID 40733904

• On ultrafast x-ray scattering methods for magnetism ADVANCES IN PHYSICS-X Plumley, R., Chitturi, S. R., Peng, C., Assefa, T. A., Burdet, N., Shen, L., Chen, Z., Reid, A. H., Dakovski, G. L., Seaberg, M. H., O'Dowd, F., Montoya, S. A., Chen, H., Okullo, A., Mardanya, S., Kevan, S. D., Fischer, P., Fullerton, E. E., Sinha, S. K., Colocho, W., Lutman, A., Decker, F., Roy, S., Fujioka, J., Tokura, Y., Minitti, M. P., Johnson, J. A., Hoffmann, M., Amoo, M. E., Feiguin, A., Yoon, C., Thayer, J., Nashed, Y., Jia, C., Bansil, A., Chowdhury, S., Lindenberg, A. M., Dunne, M., Blackburn, E., Turner, J. J. 2024; 9 (1)

  View details for DOI 10.1080/23746149.2024.2423935

  View details for Web of Science ID 001361792300001

• Understanding the superconductivity and charge density wave interaction through quasi-static lattice fluctuations. Proceedings of the National Academy of Sciences of the United States of America Porter, Z., Shen, L., Plumley, R., Burdet, N. G., Petsch, A. N., Wen, J., Drucker, N. C., Peng, C., Chen, X. M., Fluerasu, A., Blackburn, E., Coslovich, G., Hawthorn, D. G., Turner, J. J. 2024; 121 (50): e2412182121

  Abstract

  In unconventional superconductors, coupled charge and lattice degrees of freedom can manifest in ordered phases of matter that are intertwined. In the cuprate family, fluctuating short-range charge correlations can coalesce into a longer-range charge density wave (CDW) order which is thought to intertwine with superconductivity, yet the nature of the interaction is still poorly understood. Here, by measuring subtle lattice fluctuations in underdoped YBa2Cu3O6+y on quasi-static timescales (thousands of seconds) through X-ray photon correlation spectroscopy, we report sensitivity to both superconductivity and CDW. The atomic lattice shows remarkably faster relaxational dynamics upon approaching the superconducting transition at Tc ≈ 65 K. By tracking the momentum dependence, we show that the intermediate scattering function almost monotonically scales with the relaxation distance of atoms away from their average positions above Tc and in the presence of the CDW state, while this peculiar trend is reversed for other temperatures. These observations are consistent with an incipient CDW stabilized by local strain. This work provides insights into the crucial role of relaxational atomic fluctuations for understanding the electronic physics cuprates, which are inherently disordered due to carrier doping.

  View details for DOI 10.1073/pnas.2412182121

  View details for PubMedID 39630858

• 3D Heisenberg universality in the van der Waals antiferromagnet NiPS₃ NPJ QUANTUM MATERIALS Plumley, R., Mardanya, S., Peng, C., Nokelainen, J., Assefa, T., Shen, L., Burdet, N., Porter, Z., Petsch, A., Israelski, A., Chen, H., Lee, J., Morley, S., Roy, S., Fabbris, G., Blackburn, E., Feiguin, A., Bansil, A., Lee, W., Lindenberg, A. M., Chowdhury, S., Dunne, M., Turner, J. J. 2024; 9 (1)

  View details for DOI 10.1038/s41535-024-00696-6

  View details for Web of Science ID 001366178200001

• Capturing dynamical correlations using implicit neural representations. Nature communications Chitturi, S. R., Ji, Z., Petsch, A. N., Peng, C., Chen, Z., Plumley, R., Dunne, M., Mardanya, S., Chowdhury, S., Chen, H., Bansil, A., Feiguin, A., Kolesnikov, A. I., Prabhakaran, D., Hayden, S. M., Ratner, D., Jia, C., Nashed, Y., Turner, J. J. 2023; 14 (1): 5852

  Abstract

  Understanding the nature and origin of collective excitations in materials is of fundamental importance for unraveling the underlying physics of a many-body system. Excitation spectra are usually obtained by measuring the dynamical structure factor, S(Q, ω), using inelastic neutron or x-ray scattering techniques and are analyzed by comparing the experimental results against calculated predictions. We introduce a data-driven analysis tool which leverages 'neural implicit representations' that are specifically tailored for handling spectrographic measurements and are able to efficiently obtain unknown parameters from experimental data via automatic differentiation. In this work, we employ linear spin wave theory simulations to train a machine learning platform, enabling precise exchange parameter extraction from inelastic neutron scattering data on the square-lattice spin-1 antiferromagnet La2NiO4, showcasing a viable pathway towards automatic refinement of advanced models for ordered magnetic systems.

  View details for DOI 10.1038/s41467-023-41378-4

  View details for PubMedID 37730824

  View details for PubMedCentralID 8662964

• Testing the data framework for an AI algorithm in preparation for high data rate X-ray facilities Chen, H., Chitturi, S. R., Plumley, R., Shen, L., Drucker, N. C., Burdet, N., Peng, C., Mardanya, S., Ratner, D., Mishra, A., Yoon, C., Song, S., Chollet, M., Fabbris, G., Dunne, M., Nelson, S., Li, M., Lindenberg, A., Jia, C., Nashed, Y., Bansil, A., Chowdhury, S., Feiguin, A. E., Turner, J. J., Thayer, J. B., IEEE IEEE. 2022: 1-9

  View details for DOI 10.1109/XLOOP56614.2022.00006

  View details for Web of Science ID 000968746500001

• Speckle correlation as a monitor of X-ray free-electron laser induced crystal lattice deformation. Journal of synchrotron radiation Plumley, R. n., Sun, Y. n., Teitelbaum, S. n., Song, S. n., Sato, T. n., Chollet, M. n., Nelson, S. n., Wang, N. n., Sun, P. n., Robert, A. n., Fuoss, P. n., Sutton, M. n., Zhu, D. n. 2020; 27 (Pt 6): 1470–76

  Abstract

  X-ray free-electron lasers (X-FELs) present new opportunities to study ultrafast lattice dynamics in complex materials. While the unprecedented source brilliance enables high fidelity measurement of structural dynamics, it also raises experimental challenges related to the understanding and control of beam-induced irreversible structural changes in samples that can ultimately impact the interpretation of experimental results. This is also important for designing reliable high performance X-ray optical components. In this work, X-FEL beam-induced lattice alterations are investigated by measuring the shot-to-shot evolution of near-Bragg coherent scattering from a single crystalline germanium sample. It is shown that X-ray photon correlation analysis of sequential speckle patterns measurements can be used to monitor the nature and extent of lattice rearrangements. Abrupt, irreversible changes are observed following intermittent high-fluence monochromatic X-ray pulses, thus revealing the existence of a threshold response to X-FEL pulse intensity.

  View details for DOI 10.1107/S1600577520011509

  View details for PubMedID 33147171

• Compact hard x-ray split-delay system based on variable-gap channel-cut crystals OPTICS LETTERS Sun, Y., Wang, N., Song, S., Sun, P., Chollet, M., Sato, T., van Driel, T. B., Nelson, S., Plumley, R., Montana-Lopez, J., Teitelbaum, S. W., Haber, J., Hastings, J. B., Baron, A. Q. R., Sutton, M., Fuoss, P. H., Robert, A., Zhu, D. 2019; 44 (10): 2582–85

  Abstract

  We present the concept and a prototypical implementation of a compact x-ray split-delay system that is capable of performing continuous on-the-fly delay scans over a range of ∼10  ps with sub-100 nanoradian pointing stability. The system consists of four channel-cut silicon crystals, two of which have gradually varying gap sizes from intentional 5 deg asymmetric cuts. The delay adjustment is realized by linear motions of these two monolithic varying-gap channel cuts, where the x-ray beam experiences pairs of anti-parallel reflections, and thus becomes less sensitive in output beam pointing to motion imperfections of the translation stages. The beam splitting is accomplished by polished crystal edges. A high degree of mutual coherence between the two branches at the focus is observed by analyzing small-angle coherent x-ray scattering patterns. We envision a wide range of applications including single-shot x-ray pulse temporal diagnostics, studies of high-intensity x-ray-matter interactions, as well as measurement of dynamics in disordered material systems using split-pulse x-ray photon correlation spectroscopy.

  View details for DOI 10.1364/OL.44.002582

  View details for Web of Science ID 000467906400050

  View details for PubMedID 31090737