The origin of mass is one of the deepest mysteries in science. Neutrons and protons, which account for almost all visible mass in the Universe, emerged from a primordial plasma through a cataclysmic phase transition microseconds after the Big Bang. However, most mass in the Universe is invisible. The existence of dark matter, which interacts with our world so weakly that it is essentially undetectable, has been established from its galactic-scale gravitational effects. Here we describe results from the first truly physical calculations of the cosmic phase transition and a groundbreaking first-principles investigation into composite dark matter, studies impossible with previous state-of-the-art methods and resources. By inventing a powerful new algorithm, "DSDR," and implementing it effectively for contemporary supercomputers, we attain excellent strong scaling, perfect weak scaling to the LLNL BlueGene/Q two million cores, sustained speed of 7.2 petaflops, and time-to-solution speedup of more than 200 over the previous state-of-the-art.

Numerical simulations of the strong nuclear force, known as quantum chromodynamics or QCD, have proven to be a demanding, forefront problem in high-performance computing. In this report, we describe a new computer, QCDOC (QCD On a Chip), designed for optimal price/performance in the study of QCD. QCDOC uses a six-dimensional, low-latency mesh network to connect processing nodes, each of which includes a single custom ASIC, designed by our collaboration and built by IBM, plus DDR SDRAM. Each node has a peak speed of 1Gigaflops and two 12,288node, 10+ Teraflops machines are to be completed in the fall of 2004. Currently, a 512 node machine is running, delivering efficiencies as high as 45% of peak on the conjugate gradient solvers that dominate our calculations and a 4096-node machine with a cost of $1.6M is under construction. This should give us a price/performance less than $1per sustained Megaflops.

We discuss the work of the QCDSP collaboration to build an inexpensive Teraflop scale massively parallel computer suitable for computations in Quantum Chromodynamics (QCD). The computer is a collection of nodes connected in a four dimensional toroidial grid with nearest neighbor bit serial communications. A node is composed of a Texas Instruments Digital Signal Processor (DSP), memory, and a custom made communications and memory controller chip. An 8192 node computer with a peak speed of 0.4 Teraflops is being constructed at Columbia University for a cost of $1.8 Million. A 12,288-node machine with a peak speed of 0.6 Teraflops is being constructed for the RIKEN Brookhaven Research Center. Other computers have been built including a 50 Gigaflop version for Florida State University.

A parallel processor specially designed for an important problem in theoretical physics is described. The final device will contain 256 nodes running in lock-step in a SIMD mode with a computational power of 4 billion 22-bit floating point operations per second. Each node is controlled by an Intel 80286/287 microprocessor, contains 160K bits of memory and has a pipelined, microprogrammable arithmetic unit which performs floating point multiplications and additions. The nodes are interconnected in a two-dimensional rectangular grid so that vectorized arithmetic can be performed using data stored on any two adjacent nodes.