14,396 research outputs found
Characterizing and Subsetting Big Data Workloads
Big data benchmark suites must include a diversity of data and workloads to
be useful in fairly evaluating big data systems and architectures. However,
using truly comprehensive benchmarks poses great challenges for the
architecture community. First, we need to thoroughly understand the behaviors
of a variety of workloads. Second, our usual simulation-based research methods
become prohibitively expensive for big data. As big data is an emerging field,
more and more software stacks are being proposed to facilitate the development
of big data applications, which aggravates hese challenges. In this paper, we
first use Principle Component Analysis (PCA) to identify the most important
characteristics from 45 metrics to characterize big data workloads from
BigDataBench, a comprehensive big data benchmark suite. Second, we apply a
clustering technique to the principle components obtained from the PCA to
investigate the similarity among big data workloads, and we verify the
importance of including different software stacks for big data benchmarking.
Third, we select seven representative big data workloads by removing redundant
ones and release the BigDataBench simulation version, which is publicly
available from http://prof.ict.ac.cn/BigDataBench/simulatorversion/.Comment: 11 pages, 6 figures, 2014 IEEE International Symposium on Workload
Characterizatio
Roadmap to Majorana surface codes
Surface codes offer a very promising avenue towards fault-tolerant quantum
computation. We argue that two-dimensional interacting networks of Majorana
bound states in topological superconductor/semiconductor heterostructures hold
several distinct advantages in that direction, both concerning the hardware
realization and the actual operation of the code. We here discuss how
topologically protected logical qubits in this Majorana surface code
architecture can be defined, initialized, manipulated, and read out. All
physical ingredients needed to implement these operations are routinely used in
topologically trivial quantum devices. In particular, we show that by means of
quantum interference terms in linear conductance measurements, composite
single-electron pumping protocols, and gate-tunable tunnel barriers, the full
set of quantum gates required for universal quantum computation can be
implemented.Comment: 23 pages, 8 figure
Cross-verification of independent quantum devices
Quantum computers are on the brink of surpassing the capabilities of even the
most powerful classical computers. This naturally raises the question of how
one can trust the results of a quantum computer when they cannot be compared to
classical simulation. Here we present a verification technique that exploits
the principles of measurement-based quantum computation to link quantum
circuits of different input size, depth, and structure. Our approach enables
consistency checks of quantum computations within a device, as well as between
independent devices. We showcase our protocol by applying it to five
state-of-the-art quantum processors, based on four distinct physical
architectures: nuclear magnetic resonance, superconducting circuits, trapped
ions, and photonics, with up to 6 qubits and 200 distinct circuits
Full-Stack, Real-System Quantum Computer Studies: Architectural Comparisons and Design Insights
In recent years, Quantum Computing (QC) has progressed to the point where
small working prototypes are available for use. Termed Noisy Intermediate-Scale
Quantum (NISQ) computers, these prototypes are too small for large benchmarks
or even for Quantum Error Correction, but they do have sufficient resources to
run small benchmarks, particularly if compiled with optimizations to make use
of scarce qubits and limited operation counts and coherence times. QC has not
yet, however, settled on a particular preferred device implementation
technology, and indeed different NISQ prototypes implement qubits with very
different physical approaches and therefore widely-varying device and machine
characteristics.
Our work performs a full-stack, benchmark-driven hardware-software analysis
of QC systems. We evaluate QC architectural possibilities, software-visible
gates, and software optimizations to tackle fundamental design questions about
gate set choices, communication topology, the factors affecting benchmark
performance and compiler optimizations. In order to answer key cross-technology
and cross-platform design questions, our work has built the first top-to-bottom
toolflow to target different qubit device technologies, including
superconducting and trapped ion qubits which are the current QC front-runners.
We use our toolflow, TriQ, to conduct {\em real-system} measurements on 7
running QC prototypes from 3 different groups, IBM, Rigetti, and University of
Maryland. From these real-system experiences at QC's hardware-software
interface, we make observations about native and software-visible gates for
different QC technologies, communication topologies, and the value of
noise-aware compilation even on lower-noise platforms. This is the largest
cross-platform real-system QC study performed thus far; its results have the
potential to inform both QC device and compiler design going forward.Comment: Preprint of a publication in ISCA 201
Demonstration of Universal Parametric Entangling Gates on a Multi-Qubit Lattice
We show that parametric coupling techniques can be used to generate selective
entangling interactions for multi-qubit processors. By inducing coherent
population exchange between adjacent qubits under frequency modulation, we
implement a universal gateset for a linear array of four superconducting
qubits. An average process fidelity of is estimated for
three two-qubit gates via quantum process tomography. We establish the
suitability of these techniques for computation by preparing a four-qubit
maximally entangled state and comparing the estimated state fidelity against
the expected performance of the individual entangling gates. In addition, we
prepare an eight-qubit register in all possible bitstring permutations and
monitor the fidelity of a two-qubit gate across one pair of these qubits.
Across all such permutations, an average fidelity of
is observed. These results thus offer a path to a scalable architecture with
high selectivity and low crosstalk
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