213 research outputs found
Investigating the Feasibility of Integrating Pavement Friction and Texture Depth Data in Modeling for INDOT PMS
Under INDOT’s current friction testing program, the friction is measured annually on interstates but only once every three years on non-interstate roadways. The state’s Pavement Management System, however, would require current data if friction were to be included in the PMS. During routine pavement condition monitoring for the PMS, texture data is collected annually. This study explored the feasibility of using this pavement texture data to estimate the friction during those years when friction is not measured directly. After multi0ple approaches and a wide variety of ways of examining the currently available data and texture measuring technologies, it was determined that it is not currently feasible to use the texture data as a surrogate for friction testing. This is likely because the lasers used at this time are not capable of capturing the small-scale pavement microtexture. This situation may change, however, with advances in laser or photo interpretation technologies and improved access to materials data throughout the INDOT pavement network
Sub-system self-consistency in coupled cluster theory
In this Communication, we provide numerical evidence indicating that the
standard single-reference coupled-cluster (CC) energies can be calculated
alternatively to its copybook definition. We demonstrate that the CC energies
can be reconstructed by diagonalizing the effective Hamiltonians describing
correlated sub-systems of the many-body system. In the extreme case, we provide
numerical evidence that the CC energy can be reproduced through the
diagonalization of the effective Hamiltonian describing sub-system composed of
a single electron. These properties of CC formalism can be exploited to design
protocols to define effective interactions in sub-systems used as a probe to
calculate the energy of the entire system and introduce a new type of
self-consistency for approximate CC approaches.Comment: arXiv admin note: text overlap with arXiv:2111.0321
Mapping renormalized coupled cluster methods to quantum computers through a compact unitary representation of non-unitary operators
Non-unitary theories are commonly seen in the classical simulations of
quantum systems. Among these theories, the method of moments of coupled-cluster
equations (MMCCs) and the ensuing classes of the renormalized coupled-cluster
(CC) approaches have evolved into one of the most accurate approaches to
describe correlation effects in various quantum systems. The MMCC formalism
provides an effective way for correcting energies of approximate CC
formulations (parent theories) using moments, or CC equations, that are not
used to determine approximate cluster amplitudes. In this paper, we propose a
quantum algorithm for computing MMCC ground-state energies that provide two
main advantages over classical computing or other quantum algorithms: (i) the
possibility of forming superpositions of CC moments of arbitrary ranks in the
entire Hilbert space and using an arbitrary form of the parent cluster operator
for MMCC expansion; and (ii) significant reduction in the number of
measurements in quantum simulation through a compact unitary representation for
a generally non-unitary operator. We illustrate the robustness of our approach
over a broad class of test cases, including ~40 molecular systems with varying
basis sets encoded using 4~40 qubits, and exhibit the detailed MMCC analysis
for the 8-qubit half-filled, four-site, single impurity Anderson model and
12-qubit hydrogen fluoride molecular system from the corresponding noise-free
and noisy MMCC quantum computations. We also outline the extension of MMCC
formalism to the case of unitary CC wave function ansatz
Integrating Subsystem Embedding Subalgebras and Coupled Cluster Green's Function: A Theoretical Foundation for Quantum Embedding in Excitation Manifold
In this study, we introduce a novel approach to coupled-cluster Green's
function (CCGF) embedding by seamlessly integrating conventional CCGF theory
with the state-of-the-art sub-system embedding sub-algebras coupled cluster
(SES-CC) formalism. This integration focuses primarily on delineating the
characteristics of the sub-system and the corresponding segments of the Green's
function, defined explicitly by active orbitals. Crucially, our work involves
the adaptation of the SES-CC paradigm, addressing the left eigenvalue problem
through a distinct form of Hamiltonian similarity transformation. This
advancement not only facilitates a comprehensive representation of the
interaction between the embedded sub-system and its surrounding environment but
also paves the way for the quantum mechanical description of multiple embedded
domains, particularly by employing the emergent quantum flow algorithms. Our
theoretical underpinnings further set the stage for a generalization to
multiple embedded sub-systems. This expansion holds significant promise for the
exploration and application of non-equilibrium quantum systems, enhancing the
understanding of system-environment interactions. In doing so, the research
underscores the potential of SES-CC embedding within the realm of quantum
computations and multi-scale simulations, promising a good balance between
accuracy and computational efficiency
Quantum flow algorithms for simulating many-body systems on quantum computers
We conducted quantum simulations of strongly correlated systems using the
quantum flow (QFlow) approach, which enables sampling large sub-spaces of the
Hilbert space through coupled eigenvalue problems in reduced dimensionality
active spaces. Our QFlow algorithms significantly reduce circuit complexity and
pave the way for scalable and constant-circuit-depth quantum computing. Our
simulations show that QFlow can optimize the collective number of wave function
parameters without increasing the required qubits using active spaces having an
order of magnitude fewer number of parameters
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