Particle Weights and their Disintegration I

The notion of Wigner particles is attached to irreducible unitary representations of the Poincare group, characterized by parameters m and s of mass and spin, respectively. However, the Lorentz symmetry is broken in theories with long-range interactions, rendering this approach inapplicable (infraparticle problem). A unified treatment of both particles and infraparticles via the concept of particle weights can be given within the framework of Local Quantum Physics. They arise as temporal limits of physical states in the vacuum sector and describe the asymptotic particle content. In this paper their definition and characteristic properties are worked out in detail. The existence of the temporal limits is established by use of suitably defined seminorms which are also essential in proving the characteristic features of particle weights.Comment: 33 pages, amslatex, mathptm, minor corrections including numbering schem

The Concept of Particle Weights in Local Quantum Field Theory

The concept of particle weights has been introduced by Buchholz and the author in order to obtain a unified treatment of particles as well as (charged) infraparticles which do not permit a definition of mass and spin according to Wigner's theory. Particle weights arise as temporal limits of physical states in the vacuum sector and describe the asymptotic particle content. Following a thorough analysis of the underlying notion of localizing operators, we give a precise definition of this concept and investigate the characteristic properties. The decomposition of particle weights into pure components which are linked to irreducible representations of the quasi-local algebra has been a long-standing desideratum that only recently found its solution. We set out two approaches to this problem by way of disintegration theory, making use of a physically motivated assumption concerning the structure of phase space in quantum field theory. The significance of the pure particle weights ensuing from this disintegration is founded on the fact that they exhibit features of improper energy-momentum eigenstates, analogous to Dirac's conception, and permit a consistent definition of mass and spin even in an infraparticle situation.Comment: PhD thesis, 124 pages, amslatex, mathpt

General Covariance in Algebraic Quantum Field Theory

In this review we report on how the problem of general covariance is treated within the algebraic approach to quantum field theory by use of concepts from category theory. Some new results on net cohomology and superselection structure attained in this framework are included.Comment: 61 pages, 3 figures, LaTe

Local causal structures, Hadamard states and the principle of local covariance in quantum field theory

In the framework of the algebraic formulation, we discuss and analyse some new features of the local structure of a real scalar quantum field theory in a strongly causal spacetime. In particular we use the properties of the exponential map to set up a local version of a bulk-to-boundary correspondence. The bulk is a suitable subset of a geodesic neighbourhood of any but fixed point p of the underlying background, while the boundary is a part of the future light cone having p as its own tip. In this regime, we provide a novel notion for the extended *-algebra of Wick polynomials on the said cone and, on the one hand, we prove that it contains the information of the bulk counterpart via an injective *-homomorphism while, on the other hand, we associate to it a distinguished state whose pull-back in the bulk is of Hadamard form. The main advantage of this point of view arises if one uses the universal properties of the exponential map and of the light cone in order to show that, for any two given backgrounds M and M' and for any two subsets of geodesic neighbourhoods of two arbitrary points, it is possible to engineer the above procedure such that the boundary extended algebras are related via a restriction homomorphism. This allows for the pull-back of boundary states in both spacetimes and, thus, to set up a machinery which permits the comparison of expectation values of local field observables in M and M'.Comment: 42 pages, xy package is used, typos corrected, clarifications adde

Accelerating Hamming Distance Comparisons for Locality Sensitive Hashing (LSH) using FPGAs

Kaiser M, Pilz S, Porrmann F, Hagemeyer J, Porrmann M. Accelerating Hamming Distance Comparisons for Locality Sensitive Hashing (LSH) using FPGAs. In: 12th CeBiTec Symposium - Big Data in Medicine and Biotechnology - Abstract Book. Vol 12. Bielefeld; 2018: 48-49

Accelerating Binary String Comparisons with a Scalable, Streaming-Based System Architecture Based on FPGAs

Pilz S, Porrmann F, Kaiser M, Hagemeyer J, Hogan JM, Rückert U. Accelerating Binary String Comparisons with a Scalable, Streaming-Based System Architecture Based on FPGAs. Algorithms. 2020;13(2): 47.This paper is concerned with Field Programmable Gate Arrays (FPGA)-based systems for energy-efficient high-throughput string comparison. Modern applications which involve comparisons across large data sets—such as large sequence sets in molecular biology—are by their nature computationally intensive. In this work, we present a scalable FPGA-based system architecture to accelerate the comparison of binary strings. The current architecture supports arbitrary lengths in the range 16 to 2048-bit, covering a wide range of possible applications. In our example application, we consider DNA sequences embedded in a binary vector space through Locality Sensitive Hashing (LSH) one of several possible encodings that enable us to avoid more costly character-based operations. Here the resulting encoding is a 512-bit binary signature with comparisons based on the Hamming distance. In this approach, most of the load arises from the calculation of the O ( m ∗ n ) Hamming distances between the signatures, where m is the number of queries and n is the number of signatures contained in the database. Signature generation only needs to be performed once, and we do not consider it further, focusing instead on accelerating the signature comparisons. The proposed FPGA-based architecture is optimized for high-throughput using hundreds of computing elements, arranged in a systolic array. These core computing elements can be adapted to support other string comparison algorithms with little effort, while the other infrastructure stays the same. On a Xilinx Virtex UltraScale+ FPGA (XCVU9P-2), a peak throughput of 75.4 billion comparisons per second—of 512-bit signatures—was achieved, using a design with 384 parallel processing elements and a clock frequency of 200 MHz. This makes our FPGA design 86 times faster than a highly optimized CPU implementation. Compared to a GPU design, executed on an NVIDIA GTX1060, it performs nearly five times faster

Development of Energy Models for Design Space Exploration of Embedded Many-Core Systems

This paper introduces a methodology to develop energy models for the design space exploration of embedded many-core systems. The design process of such systems can benefit from sophisticated models. Software and hardware can be specifically optimized based on comprehensive knowledge about application scenario and hardware behavior. The contribution of our work is an automated framework to estimate the energy consumption at an arbitrary abstraction level without the need to provide further information about the system. We validated our framework with the configurable many-core system CoreVA-MPSoC. Compared to a simulation of the CoreVA-MPSoC on gate level in a 28nm FD-SOI standard cell technology, our framework shows an average estimation error of about 4%.Comment: Presented at HIP3ES, 201

A Reconfigurable Heterogeneous Microserver Architecture for Energy-efficient Computing

Kaiser M, Griessl R, Hagemeyer J, et al. A Reconfigurable Heterogeneous Microserver Architecture for Energy-efficient Computing. In: Third International Workshop on Heterogeneous High-performance Reconfigurable Computing (H2RC'17). Denver, CO; 2017

System-Level Analysis of Network Interfaces for Hierarchical MPSoCs

Ax J, Sievers G, Flasskamp M, Kelly W, Jungeblut T, Porrmann M. System-Level Analysis of Network Interfaces for Hierarchical MPSoCs. In: Proceedings of the 8th International Workshop on Network on Chip Architectures (NoCArc). New York, NY, USA: ACM; 2015: 3-8.Network Interfaces (NIs) are used in Multiprocessor System-on-Chips (MPSoCs) to connect CPUs to a packet switched Network-on-Chip. In this work we introduce a new NI architecture for our hierarchical CoreVA-MPSoC. The CoreVA-MPSoC targets streaming applications in embedded systems. The main contribution of this paper is a system-level analysis of different NI configurations, considering both software and hardware costs for NoC communication. Different configurations of the NI are compared using a benchmark suite of 10 streaming applications. The best performing NI configuration shows an average speedup of 20 for a CoreVA-MPSoC with 32 CPUs compared to a single CPU. Furthermore, we present physical implementation results using a 28 nm FD-SOI standard cell technology. A hierarchical MPSoC with 8 CPU clusters and 4 CPUs in each cluster running at 800 MHz requires an area of 4.56 mm²