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Tensor network methods are becoming increasingly important for high-energy physics, condensed matter physics and quantum information science (QIS). We discuss the impact of tensor network methods on lattice field theory, quantum gravity and QIS in the context of High Energy Physics (HEP). These tools will target calculations for strongly interacting systems that are made difficult by sign problems when conventional Monte Carlo and other importance sampling methods are used. Further development of methods and software will be needed to make a significant impact in HEP. We discuss the roadmap to perform quantum chromodynamics (QCD) related calculations in the coming years. The research is labor intensive and requires state of the art computational science and computer science input for its development and validation. We briefly discuss the overlap with other science domains and industry., Comment: Contribution to Snowmass 2021, preliminary version

Since 2005 ESO has been working with its community and industry to develop an extremely large optical/infrared telescope. ESO's Extremely Large Telescope, or ELT for short, is a revolutionary ground-based telescope that will have a 39-metre main mirror and will be the largest visible and infrared light telescope in the world. To address specific topics that are needed for the science operations and calibrations of the telescope, thirteen specific working groups were created to coordinate the effort between ESO, the instrument consortia, and the wider community. We describe here the goals of these working groups as well as their achievements so far., Comment: 8 pages, 4 figures

This whitepaper is an outcome of the workshop Intersections between Nuclear Physics and Quantum Information held at Argonne National Laboratory on 28-30 March 2018 [www.phy.anl.gov/npqi2018/]. The workshop brought together 116 national and international experts in nuclear physics and quantum information science to explore opportunities for the two fields to collaborate on topics of interest to the U.S. Department of Energy (DOE) Office of Science, Office of Nuclear Physics, and more broadly to U.S. society and industry. The workshop consisted of 22 invited and 10 contributed talks, as well as three panel discussion sessions. Topics discussed included quantum computation, quantum simulation, quantum sensing, nuclear physics detectors, nuclear many-body problem, entanglement at collider energies, and lattice gauge theories., 22 pages, Outcome of the workshop: Intersections between Nuclear Physics and Quantum Information

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Improvements in brightness and coherent flux of about two orders of magnitude over operational storage ring based light sources are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source, making use of the existing infrastructure, thereby reducing cost and time needed to reach full scientific productivity on a large number of beamlines. An R&D program was started at LBNL to further develop the technologies necessary for diffraction-limited storage rings. It involves many areas, and focuses on the specific needs of soft x-ray facilities: NEG coating of small chambers, swap-out injection, bunch lengthening, magnets/radiation production, x-ray optics, and beam physics design optimization. Hardware prototypes have been built and concepts and equipment was tested in beam tests on the existing ALS., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

Current Laser Guide Star (LGS) Adaptive Optics (AO) systems disregard all tip-tilt wavefront information received from the LGS Wavefront Sensors (WFS), as it is considered irretrievably entangled with the up-link turbulence that the laser encounters as it passes through the atmosphere to form a guide star. Consequently, they must still observe a Natural Guide Star (NGS) in order to correct for tip-tilt aberrations.A method has recently been presented that use the tomographic capabilities of centre-launched, multi-LGS AO systems to predict the LGS uplink turbulence and hence allow correction with a reduced requirement on the NGS, or potentially no NGS requirement at all for some scientific applications. This method is summarised here, and its limitations discussed. Due to the increased separation of the laser beams at higher altitude, the method is more effective for correction of tip-tilt from high altitude turbulence, with performance approaching that of tomographic LGS AO with a tip-tilt NGS. The method is less successful for correcting tip-tilt contributions from low altitudes, though potential mitigation of this is considered.We finally discuss the methods potential for ELT scale operation. Due to the large aperture size, and large LGS separation, it is expected that the method would be more effective for larger telescopes.

Improvements in brightness and coherent flux of about two orders of magnitude over operational storage ring based light sources are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source, making use of the existing infrastructure, thereby reducing cost and time needed to reach full scientific productivity on a large number of beamlines. An R&D program funded by internal laboratory funds was started at LBNL to further develop the technologies necessary for diffraction-limited storage rings (DLSR). It initially involves five areas, and focuses on the specific needs of soft x-ray facilities: vacuum system/NEG coating of small chambers, injection/pulsed magnets, RF systems/bunch lengthening, magnets/radiation production with advanced radiation devices, and beam physics design optimization. Some hardware prototypes have been built. The work will expand in the future to demonstrate necessary key technologies at the subsystem level or in beam tests and include new areas like photon beamline optics., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

We present the spectrum of baryons in a new SU(4) gauge theory with fundamental fermion constituents. The spectrum of these bosonic baryons is of significant interest for composite dark matter theories. Here, we compare the spectrum and properties of SU(3) and SU(4) baryons, and then compute the dark-matter direct detection cross section via Higgs boson exchange for TeV-scale composite dark matter arising from a confining SU(4) gauge sector. Comparison with the latest LUX results leads to tight bounds on the fraction of the constituent-fermion mass that may arise from electroweak symmetry breaking. Lattice calculations of the dark matter mass spectrum and the Higgs-dark matter coupling are performed on quenched $16^{3} \times 32$, $32^{3} \times 64$, $48^{3} \times 96$, and $64^{3} \times128$ lattices with three different lattice spacings, using Wilson fermions with moderate to heavy pseudoscalar meson masses. Our results lay a foundation for future analytic and numerical study of composite baryonic dark matter., Comment: 18 pages, 18 figures

Quasi-static speckles are a current limitation to faint companion imaging of bright stars. Here we show through simulation and theory that an adaptive pupil mask can be used to reduce these speckles and increase the visibility of faint companions. This is achieved by placing an adaptive mask in the conjugate pupil plane of the telescope. The mask consists of a number of independently controllable elements which can either allow the light in the subaperture to pass or block it. This actively changes the shape of the telescope pupil and hence the diffraction pattern in the focal plane. By randomly blocking subapertures we force the quasi-static speckles to become dynamic. The long exposure PSF is then smooth, absent of quasi-static speckles. However, as the PSF will now contain a larger halo due to the blocking, the signal to noise ratio (SNR) is reduced requiring longer exposure times to detect the companion. For example, in the specific case of a faint companion at 5xlambda/D the exposure time to achieve the same SNR will be increased by a factor of 1.35. In addition, we show that the visibility of companions can be greatly enhanced in comparison to long-exposures, when the dark speckle method is applied to short exposure images taken with the adaptive pupil mask. We show that the contrast ratio between PSF peak and the halo is then increased by a factor of approximately 100 (5 magnitudes), and we detect companions 11 magnitudes fainter than the star at 5xlambda/D and up to 18 magnitudes fainter at 22.5xlambda/D., Comment: 8 pages, 9 figures, MNRAS, accepted 25th May 2012

We discuss methods for the calculation of disconnected diagrams and their application to various form factors of the nucleon. In particular, we present preliminary results for the strange contribution to the scalar and axial form factors, calculated with N_f=2 dynamical flavors of Wilson fermions on an anisotropic lattice., Comment: 7 pages, 5 figures, presented at Lattice 2007, Regensburg, Germany, 30 July - 4 August 2007

We study the effects of discretization on the U(1) symmetric XY model in two dimensions using the Higher Order Tensor Renormalization Group (HOTRG) approach. Regarding the $Z_N$ symmetric clock models as specific discretizations of the XY model, we compare those discretizations to ones from truncations of the tensor network formulation of the XY model based on a character expansion, and focus on the differences in their phase structure at low temperatures. We also divide the tensor network formulations into core and interaction tensors and show that the core tensor has the dominant influence on the phase structure. Lastly, we examine a perturbed form of the XY model that continuously interpolates between the XY and clock models. We examine the behavior of the additional phase transition caused by the perturbation as the magnitude of perturbation is taken to zero. We find that this additional transition has a non-zero critical temperature as the perturbation vanishes, suggesting that even small perturbations can have a significant effect on the phase structure of the theory., 12 pages, 14 figures

The Advanced Light Source (ALS) at Berkeley Lab has been updated many times and remains as one of the brightest sources for soft x-rays worldwide. However, recent developments in technology, accelerator physics and simulation techniques open the door to much larger future brightness improvements. Similar to proposals at several other 3rd generation sources, this could be achieved by reducing the horizontal emittance with a new ring based on a multi-bend achromat lattice, reusing the existing tunnel, as well as much of the infrastructure and beamlines. After studying candidate lattice designs, development efforts in the last year have concentrated on technology and physics challenges in four main areas: Injection, Vacuum Systems, Magnets and Insertion Devices, as well as main and harmonic RF systems., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

This whitepaper is an outcome of the workshop Intersections between Nuclear Physics and Quantum Information held at Argonne National Laboratory on 28-30 March 2018 [www.phy.anl.gov/npqi2018/]. The workshop brought together 116 national and international experts in nuclear physics and quantum information science to explore opportunities for the two fields to collaborate on topics of interest to the U.S. Department of Energy (DOE) Office of Science, Office of Nuclear Physics, and more broadly to U.S. society and industry. The workshop consisted of 22 invited and 10 contributed talks, as well as three panel discussion sessions. Topics discussed included quantum computation, quantum simulation, quantum sensing, nuclear physics detectors, nuclear many-body problem, entanglement at collider energies, and lattice gauge theories., Comment: 22 pages, Outcome of the workshop: Intersections between Nuclear Physics and Quantum Information