Clusters of atoms have remarkable optical properties that were exploited since the antiquity. It was only during the late 20th century though that their production was better controlled and opened the door to a better understanding of matter. Lasers are the tool of choice to study these nanoscopic objects so scientists have been blowing clusters […]

July 28, 2014 by hgpu

Diagrammatic Determinantal Quantum Monte Carlo (DDQMC) algorithms are used to solve quantum impurity models such as the Anderson model. The calculation of acceptance rates and observables during the Monte Carlo walk involves linear algebra operations whose computational expense increases with decreasing temperature. Thus, the lower boundary of the treatable temperature range is limited by the […]

April 2, 2014 by hgpu

Adiabatic techniques offer some of the most promising tools to achieve high-fidelity control of the centre-of-mass degree of freedom of single atoms. As their main requirement is to follow an eigenstate of the system, constraints on timing and field strength stability are usually low, especially for trapped systems. In this paper we present a detailed […]

September 11, 2013 by hgpu

We present a General-purpose computing on graphics processing units (GPGPU) based computational program and framework for the electronic dynamics of atomic systems under intense laser fields. We present our results using the case of hydrogen, however the code is trivially extensible to tackle problems within the single-active electron (SAE) approximation. Building on our previous work, […]

August 9, 2013 by hgpu

The resolution of dynamics in out of equilibrium quantum spin systems relies at the heart of fundamental questions among Quantum Information Processing, Statistical Mechanics and Nano-Technologies. Efficient computational simulations of interacting many-spin systems are extremely valuable tools for tackling such questions. Here, we use the Trotter-Suzuki (TS) algorithm, a well-known strategy that provides the evolution […]

May 2, 2013 by hgpu

One of the most striking features of quantum mechanics is the exponential growth of resources, required to find the states of a composite system, with the size of the system. This also is the origin of the two main bottlenecks in numerical studies of complex quantum systems, that are (i) diagonalizations of big matrices and […]

April 7, 2013 by hgpu

The Trotter-Suzuki approximation leads to an efficient algorithm for solving the time-dependent Schroedinger equation. Using existing highly optimized CPU and GPU kernels, we developed a distributed version of the algorithm that runs efficiently on a cluster. Our implementation also improves single node performance, and is able to use multiple GPUs within a node. The scaling […]

August 14, 2012 by hgpu

This MATLAB program calculates the dynamics of the reduced density matrix of an open quantum system modeled by the Feynman-Vernon model. The user gives the program a vector describing the coordinate of an open quantum system, a hamiltonian matrix describing its energy, and a spectral distribution function and temperature describing the environment’s influence on it, […]

June 1, 2012 by hgpu

We study the use of polar codes for both discrete and continuous variables Quantum Key Distribution (QKD). Although very large blocks must be used to obtain the efficiency required by quantum key distribution, and especially continuous variables quantum key distribution, their implementation on generic x86 CPUs is practical. Thanks to recursive decoding, they exhibit excellent […]

May 3, 2012 by hgpu

Open Computing Language (OpenCL) is a parallel processing language that is ideally suited for running parallel algorithms on Graphical Processing Units (GPUs). In the present work we report the development of a generic parallel single-GPU code for the numerical solution of a system of first-order ordinary differential equations (ODEs) based on the openCL model. We […]

January 31, 2012 by hgpu

It has been experimentally proven that realizing universal quantum gates using higher-radices logic is practically and technologically possible. We developed a Parallel Genetic Algorithm that synthesizes Boolean reversible circuits realized with a variety of quantum gates on qudits with various radices. In order to allow synthesizing circuits of medium sizes in the higher radix quantum […]

July 19, 2011 by hgpu

Although the need for heterogeneous chips in high performance numerical computing was identified by Chillemi and co-authors in 2001 it is only over the past five years that it has emerged as the new frontier for HPC. In this environment one or more accelerators works symbiotically, on each node, with a multi-core CPU. Two such […]

May 5, 2011 by hgpu