Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Donald Sinclair Project Name: Lattice-QCD Division: HEP Project title: Lattice simulations of Conformal and Walking Technicolor. Associated funding: DOE Other Systems: NERSC Cray XC30, "Edison" NERSC Cray XT6, "Hopper" NERSC Cluster, "Carver" Current NERSC allocation: 35,000,000 MPP hours TACC cluster, Stampede. Allocation 3,000,000 core-hours. Science: We are using our simulation methods developed for lattice QCD to study extensions of the standard model of High Energy Physics, in which the Higgs sector is strongly interacting, and the Higgs fields are composites. This has become all the more relevant with the discovery of a Higgs-like particle at the LHC at CERN. We are particularly interested in QCD-like theories whose pions play the role of the Higgs field in giving masses to the W and Z weak vector bosons. Such theories are called Technicolor theories. We are particularly interested in Walking Technicolor theories, whose slowly evolving couplings evade some of the technical difficulties associated with the phenomenology of Technicolor and Extended Technicolor theories. Our initial studies are of the thermodynamics of such theories, since these provide a simple way of measuring the scales of confinement and of chiral symmetry breaking. From such simulations, we can determine if confinement and chiral-symmetry b reaking survive the continuum limit. In this case, our chosen theory is QCD-like. If not the theory is a conformal field theory. We choose theories which 2-loop perturbation theory suggests have an infrared fixed point and are thus conformal. If chiral symmetry breaks spontaneously before this fixed point is reached, the fixed point is avoided and the theory is ultimately QCD-like. However, the close proximity of the fixed point means that there is a region where the running coupling constant evolves very slowly, i.e. the theory walks. The candidate Walking-Technicolor theory which we are studying is 'scaled up' QCD with 2 colour-sextet quarks. QCD with 2 sextet quarks has just the right number of Goldstone 'pions' (3) to give masses to the Ws and Z. It remains an open question as to whether it has a light Higgs. Because it is difficult to determine the nature of this theory, it is useful to study a closely related theory with known behaviour. We study QCD with 3 sextet quarks which is almost certainly conformal for comparison. We have a second project starting this year, namely simulations of Lattice QCD at finite quark-number chemical potential mu, using Complex Langevin methods. This is relevant to the understanding of the phases of nuclear-matter at zero and finite temperature. Cold nuclear matter is found in neutron stars. Hot nuclear matter (quark-gluon matter/plasma) is believed to be produced in relativistic heavy-ion colliders, and was certainly present in the early universe, Since the integrand of the partition function, which describes the quantum dynamics of QCD at finite mu, is complex, standard simulation methods which rely on importance sampling fail and we turn to complex Langevin simulations. Because these require using a non-compact extension of the gauge group, runaway solutions are common, and these caused earlier use of this method to fail. Recent advances indicate that at least some of these problems were associated with large gauge excursions from well-behaved gauge configura tions, and can be circumvented by judicious choice of gauge (gauge-cooling) after each field update. Project description: We perform simulations to evaluate the functional integrals of QCD-like theories formulated on a discrete space-time lattice, to enable determination of the non-perturbative aspects these theories. These include the properties of these theories at non-zero temperature, including the scales of confinement and chiral symmetry breaking, and such zero temperature properties as spectra (including the Higgs mass), decay constants and the running of the gauge coupling constant. We are particularly interested in those theories where the coupling constant evolves very slowly, since these are candidate 'Walking Technicolor' theories. Related to these are theories with an infrared fixed point (conformal field theories). Our first goal is to differentiate between these two different types of behaviour for candidate theories. We are performing simulations of QCD-like theories which are models for Walking or Conformal Technicolor. We have been studying theories which are essentially QCD but with colour-sextet rather than colour-triplet quarks. We hope to measure the running of the QCD coupling constant. For 2 or 3 flavours, 2-loop perturbation theory predicts an infrared fixed point. For 2 flavours, it is possible that a chiral condensate forms before this fixed point is reached. If so, the fixed point is avoided, the theory is confining, and chiral symmetry breaks spontaneously. However, there is a region where the coupling constant evolves very slowly. These are the properties required for a walking technicolor theory. Simulations we have performed so far at finite temperature suggest that this theory might walk. So far the results are inconclusive. For 3 flavours we know that the theory should be conformal. Simulations at N_t=6 (12^3 X 6 lattice) and N_t=8 (16^3 X 8 lattice), some of which used Fusion, did not yet show evidence of conformality. We are thus moving to N_t=12 (24^3 X 12 lattice). We started these simulations on Blues, and intend to continue them in FY2015 on Blues, while performing lower mass simulations on Edison at NERSC. Our sextet quark codes are based on our earlier triplet quark codes and use the RHMC simulation method. The Rational Hybrid Monte Carlo (RHMC) is a stochastic molecular dynamics algorithm. The functional integral of QCD is written as a partition function of a classical field theory evolving in a fictitious time. The determinant of the Dirac operator raised to a fractional power is calculated by introducing bosonic fields (pseudofermions), and sandwiching this Dirac operator raised to minus said fractional power between them. This fractional power of the Dirac operator is approximated to machine accuracy by a rational approximation. After defining this this theory on a discrete space-time lattice, the inversions required by the partial-fraction expansion of the rational approximation are performed using Krylov space methods, in particular a multi-shift extension of the conjugate gradient algorithm. A global Metropolis Monte-Carlo accept/reject step applied at the end of each trajectory removes discretization errors introduced by the numerical integration of these stochastic equations of motion. We parallelize the code by assigning a fixed number of adjacent lattice sites to each MPI task. Network bandwidth ultimately limits how small a chunk of the lattice can be assigned to each task. Our 24^3 X 12 runs will be performed on 288 cores (18 nodes) of Blues. A short benchmark run of the 24^3 X 12 code yielded 667 Gflops or 2.3 Gflops/core. Since we have seen performances of > 3 Gflops/core on machines with similar processors, we suspect that at least 3 Gflops/core should be achievable on this machine. Since we have exhausted our allocation on Blues, we cannot perform more extensive tests. Scaling tests on Fusion and on Edison at NERSC for numbers of cores from 24 up to 288 cores indicate that the per core performance increases up to 144 or 288 cores, which we believe to be related to cache usage. Our new project, simulating QCD at finite mu using Complex Langevin with Gauge Cooling, will require some code development. Our old codes do not as yet have gauge cooling and our parallel code uses SHMEM rather than MPI for communication. Since the real Langevin is the limit of our Hybrid Molecular Dynamics code (the forerunner of the RHMC method) in which there is a single update per trajectory, most of what we have discussed for the RHMC applies, and will not be repeated here. We plan to use Blues and Carver at NERSC for the early, small-lattice simulations, 8^3 X 4 on 32 cores and 8^4 on 64 cores. Because of the smaller memory requirements, allowing more efficient cache usage, we expect to get a minimum performance of 3-4 Gflops/core for this code. Our requested allocation is based on running 1 288 core job half of the time at times when the NERSC machines are experiencing slowdowns for amall jobs. Industry partnership: Project URL: http://www.hep.anl.gov/dks Current FY Hours Used: undetermined amount New FY Requested allocation: 1200000 Q1: 300000 Q2: 300000 Q3: 300000 Q4: 300000 Justification: We have not yet performed a detailed scaling analysis on Blues, however, we have such analyses performed on Fusion as well as Edison at NERSC. For Fusion, for our QCD with sextet quarks code on a 24^3 X 12 lattice running on Fusion we observed the following performances: 24 cores = 45 Gflops = 1.9 Gflops/core 48 cores = 95 Gflops = 2.0 Gflops/core 72 cores = 148 Gflops = 2.1 Gflops/core 96 cores = 220 Gflops = 2.3 Gflops/core 144 cores = 369 Gflops = 2.6 Gflops/core 288 cores = 784 Gflops = 2.7 Gflops/core For the same code and lattice size running on Edison at NERSC we observed the following performances. 24 cores = 53 Gflops = 2.2 Gflops/core 48 cores = 115 Gflops = 2.4 Gflops/core 72 cores = 191 Gflops = 2.7 Gflops/core 96 cores = 245 Gflops = 2.6 Gflops/core 144 cores = 510 Gflops = 3.5 Gflops/core 288 cores = 959 Gflops = 3.3 Gflops/core We use a custom assignment of tasks to nodes in order to minimize communications. Earlier recoding reduced the number of global reductions in the routines, which use most of the CPU time, by a factor of 2. The node codes are transparently vectorizable, to allow use of SSE instructions. Storage requirements: Thank You, The LCRC Accounts System