Database support of detector operation and data analysis in the DEAP-3600 Dark Matter experiment

The DEAP-3600 detector searches for dark matter interactions on a 3.3 tonne liquid argon target. Over nearly a decade, from start of detector construction through the end of the data analysis phase, well over 200 scientists will have contributed to the project. The DEAP-3600 detector will amass in excess of 900 TB of data representing more than 10$^{10}$ particle interactions, a few of which could be from dark matter. At the same time, metadata exceeding 80 GB will be generated. This metadata is crucial for organizing and interpreting the dark matter search data and contains both structured and unstructured information. The scale of the data collected, the important role of metadata in interpreting it, the number of people involved, and the long lifetime of the project necessitate an industrialized approach to metadata management. We describe how the CouchDB and the PostgreSQL database systems were integrated into the DEAP detector operation and analysis workflows. This integration provides unified, distributed access to both structured (PostgreSQL) and unstructured (CouchDB) metadata at runtime of the data analysis software. It also supports operational and reporting requirements

Polyethylene naphthalate film as a wavelength shifter in liquid argon detectors

Liquid argon-based scintillation detectors are important for dark matter searches and neutrino physics. Argon scintillation light is in the vacuum ultraviolet region, making it hard to be detected by conventional means. Polyethylene naphthalate (PEN), an optically transparent thermoplastic polyester commercially available as large area sheets or rolls, is proposed as an alternative wavelength shifter to the commonly-used tetraphenyl butadiene (TPB). By combining the existing literature data and spectrometer measurements relative to TPB, we conclude that the fluorescence yield and timing of both materials may be very close. The evidence collected suggests that PEN is a suitable replacement for TPB in liquid argon neutrino detectors, and is also a promising candidate for dark matter detectors. Advantages of PEN are discussed in the context of scaling-up existing technologies to the next generation of very large ktonne-scale detectors. Its simplicity has a potential to facilitate such scale-ups, revolutionizing the field.Comment: 6 pages, 3 figure

Influence of nonviable lactobacillus fermentation product in artificially reared pigs challenged with e. coli

Two trials were conducted to determine the influence of non viable lactobacillus fermentation product (LFP) in artificially reared pigs removed from sows at 24 to 36 hours postpartum. The pigs were fed a non-medicated milk replacer for 21 days in individual cages in an environmentally controlled room. In Trial I, 5 levels (0, .25, .5, 1.0, and 2.0 ml per pig per day) of LFP were used to determine the dosage rate on growth, feed efficiency, mortality rate, white blood cell count, and hematocrit (8 pigs per treatment). No detectable dosage rate was obvserved in Trial I. In Trial II, a study was conducted to determine the effect of LFP on lactobacill us and coli form (E. coli) counts, histopathology of the small intestine, growth and blood parameters. When pigs were 14 days old they received an inoculum of either a broth containing E. coli (strain K88,91; approximately billion organisms for two days) or broth without E. coli. Pigs were fed three levels of the LFP at 0, .5, and 1.0 ml per day. Pigs were sacrificed five days and seven sections of gastrointestinal tract and feces were excised to enumerate lactobacillus and coliform populations. A dose rate of .5 ml per day increased gain (P\u3c.08) and suppressed E. coli count in the stomach area without affecting lactobacillus populations.- No differences were detected with the pathological evaluation. By challenging the pigs with E. coli, jejunum (section of the small intestine) coliform and white blood cell counts were increased (P\u3c.06). These results suggest that lactobacillus fermentation product suppresses E. coli counts in the stomach and may improve gain in the artificially reared pig.; Swine Day, Manhattan, KS, November 11, 198

Quantum quench in two dimensions using the variational Baeriswyl wave function

By combining the Baeriswyl wave function with equilibrium and time-dependent variational principles, we develop a nonequilibrium formalism to study quantum quenches for two-dimensional spinless fermions with nearest-neighbor hopping and repulsion. The variational ground-state energy, the charge-density wave (CDW) order parameter, and the short-time dynamics agree convincingly with the results of numerically exact simulations. We find that, depending on the initial and final interaction strength, the quenched system either exhibits oscillatory behavior or relaxes to a time-independent steady state. The time-averaged expectation value of the CDW order parameter rises sharply when crossing from the steady-state regime to the oscillating regime, indicating that the system, being nonintegrable, shows signs of thermalization with an effective temperature above or below the equilibrium critical temperature, respectively. © 2016 American Physical Society

Observing non-ergodicity due to kinetic constraints in tilted Fermi-Hubbard chains

The thermalization of isolated quantum many-body systems is deeply related to fundamental questions of quantum information theory. While integrable or many-body localized systems display non-ergodic behavior due to extensively many conserved quantities, recent theoretical studies have identified a rich variety of more exotic phenomena in between these two extreme limits. The tilted one-dimensional Fermi-Hubbard model, which is readily accessible in experiments with ultracold atoms, emerged as an intriguing playground to study non-ergodic behavior in a clean disorder-free system. While non-ergodic behavior was established theoretically in certain limiting cases, there is no complete understanding of the complex thermalization properties of this model. In this work, we experimentally study the relaxation of an initial charge-density wave and find a remarkably long-lived initial-state memory over a wide range of parameters. Our observations are well reproduced by numerical simulations of a clean system. Using analytical calculations we further provide a detailed microscopic understanding of this behavior, which can be attributed to emergent kinetic constraints.Comment: accepted in Nature Communication

Static Holes in the Geometrically Frustrated Bow Tie Ladder

We investigate the doping of a geometrically frustrated spin ladder with static holes by a complementary approach using exact diagonalization and quantum dimers. Results for thermodynamic properties, the singlet density of states, the hole-binding energy and the spin correlations will be presented. For the undoped systems the ground state is non-degenerate, with translationally invariant nearest-neighbor spin correlations. In the doped case, we find that static holes polarize their vicinity by a localization of singlets in order to reduce the frustration. This polarization induces short range repulsive forces between two holes and an oscillatory behavior of the long range two-hole energy. For most quantities investigated, we find very good agreement between the quantum dimer approach and the results from exact diagonalization.Comment: 7 pages, 9 eps figure

Entanglement spectra of critical and near-critical systems in one dimension

The entanglement spectrum of a pure state of a bipartite system is the full set of eigenvalues of the reduced density matrix obtained from tracing out one part. Such spectra are known in several cases to contain important information beyond that in the entanglement entropy. This paper studies the entanglement spectrum for a variety of critical and near-critical quantum lattice models in one dimension, chiefly by the iTEBD numerical method, which enables both integrable and non-integrable models to be studied. We find that the distribution of eigenvalues in the entanglement spectra agrees with an approximate result derived by Calabrese and Lefevre to an accuracy of a few percent for all models studied. This result applies whether the correlation length is intrinsic or generated by the finite matrix size accessible in iTEBD. For the transverse Ising model, the known exact results for the entanglement spectrum are used to confirm the validity of the iTEBD approach. For more general models, no exact result is available but the iTEBD results directly test the hypothesis that all moments of the reduced density matrix are determined by a single parameter.Comment: 6 pages, 5 figure

Interacting internal waves explain global patterns of interior ocean mixing

Across the stable density stratification of the abyssal ocean, deep dense water is slowly propelled upward by sustained, though irregular, turbulent mixing. The resulting mean upwelling is key to setting large-scale oceanic circulation properties, such as heat and carbon transport. It is generally accepted that in the ocean interior, this turbulent mixing is caused mainly by breaking internal waves, which are predominantly generated by winds and tides, interact nonlinearly, thereby fluxing energy down to ever smaller scales, and finally become unstable, break and mix the water column. This paradigm forms the conceptual backbone of the widely used Finescale Parameterization. This formula estimates small-scale mixing from the readily observable internal wave activity at larger scales and theoretical scaling laws for the downscale nonlinear energy flux, but has never been fully explained theoretically. Here, we close this gap using wave-wave interaction theory with input from both localized high-resolution experiments and combined global observational datasets. We find near-ubiquitous agreement between our predictions, derived from first-principles alone, and the observed mixing patterns in the global ocean interior. Our findings lay the foundations for a new type of wave-driven mixing parameterization for ocean general circulation models that is entirely physics-based, which is key to reliably represent climate states that differ substantially from today's

Exact and simple results for the XYZ and strongly interacting fermion chains

We conjecture exact and simple formulas for physical quantities in two quantum chains. A classic result of this type is Onsager, Kaufman and Yang's formula for the spontaneous magnetization in the Ising model, subsequently generalized to the chiral Potts models. We conjecture that analogous results occur in the XYZ chain when the couplings obey J_xJ_y + J_yJ_z + J_x J_z=0, and in a related fermion chain with strong interactions and supersymmetry. We find exact formulas for the magnetization and gap in the former, and the staggered density in the latter, by exploiting the fact that certain quantities are independent of finite-size effects