Racah Institute of Physics
University of Washington
Ubirajara van Kolck
IPN Orsay/University of Arizona
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INT Program INT-16-1
Nuclear Physics from Lattice QCD
March 21 - May 27, 2016
The last decade has witnessed dramatic progress in three directions: lattice quantum chromodynamics
(LQCD), nuclear effective field theories (NEFT) and ab initio nuclear-structure methods (AIM). All of these research directions aim to fully base nuclear
physics upon the underlying theory of strong interactions, QCD, and to provide predictions for nuclear observables with fully controlled uncertainties. The
INT program "Nuclear Physics from LQCD" will bring together leading experts in these three subdisciplines and plans to build a community that will analyze,
direct and support the LQCD effort. Each of the three subfields mentioned above has specific computational and theoretical problems, such as finite-volume
artifacts and signal-to-noise issues in LQCD, ultraviolet-cutoff dependence in NEFT, and model-space limitations in AIMs. These problems significantly affect
the scope of the results, and, in particular, the uncertainties associated with quantitative calculations of observables of interest. A few of the key questions
that would be addressed include:
input, such as few-body forces, in order to make predictions for nuclei. What observables should LQCD compute beyond the binding energies of light nuclei in order to impact ab initio calculations?
LQCD calculations are simpler and, with the current computational resources, more precise at large unphysical quark masses. How does one extrapolate these results to the physical point using NEFTs, and what is the range of validity of these effective field theories?
The statistical analysis of large data sets and finite-volume methods are technologies common to both LQCD and ab initio nuclear-structure physicists. Are there interesting areas of overlap in these and other technologies that could lead to progress in one or both of these subdisciplines?
In each of the three subdisciplines, ultraviolet and infrared cutoffs are imposed to limit the model spaces where explicit calculations are performed. Can the errors due to these truncations be estimated, and reliable extrapolation methods be developed?
The connection between LQCD calculations of energy eigenvalues and the physical scattering amplitudes is well developed in the two-particle sector by
the use of the Lüscher method. Can we expect to reach the same level of maturity in the three(multi)-particle sector? What are the prospects and practical
limitations of newly-developed formalisms above multi-particle inelastic thresholds?
Theoretical uncertainties in nuclear matrix elements continue to
be a dominant source of error in the program that aims to test the standard model and search for new physics. What are the prospects of first-principles QCD
calculations of nuclear matrix elements, and what role LQCD can play in improving/complementing the NEFT and ab initio many-body calculations of these quantities?
Given the rapid advances in high-performance computing which are allowing for ever-more sophisticated LQCD and ab initio nuclear-structure
it is timely for the community to start taking steps towards overcoming all such conceptual, formal and technical challenges. Such progress would boost
us towards the common goal of making reliable predictions for some of the most important nuclear physics observables from the underlying theory of QCD.
We encourage all the interested scientists in these subfields of nuclear physics to apply. The participation of, and input from, young as well as
underrepresented researchers in these areas are particularly welcome. We plan to follow the standard format of one daily talk with plenty of time for
discussions and collaborations.