Determination of Lattice QCD Equation of State at a Finite Chemical Potential

Mitra, S (2024) Determination of Lattice QCD Equation of State at a Finite Chemical Potential. In: 25th DAE-BRNS High Energy Physics Symposium, HEPS 2022, 12 December 2022through 16 December 2022, IISER Mohali, pp. 209-212.

PDF Spr_pro_phy_304_HEPS_2024.pdf - Published Version Restricted to Registered users only Download (440kB) | Request a copy

Abstract

The Taylor expansion of thermodynamic observables at a finite baryon chemical potential μB is a well-known approach to circumvent the fermion sign problem. The reliability of a Taylor estimate is determined by the radius of convergence, a reasonable estimate of which requires sufficiently higher order calculations in μB. But, owing to the associated difficulty and limitations of precision in calculating these higher-order Taylor coefficients, it becomes essential to look for various alternative expansion schemes. Exponential Resummation to all orders in μB is one such promising alternative scheme, which has been recently proposed in Phys. Rev. Lett. 128, 022001 (2022). Unfortunately, the resummation formulation gets affected by the appearance of biased estimates. The effects from these estimates can become very drastic and can radically misdirect the calculations for higher values and orders of μ and also with increasing order of μ derivatives of free energy. In this work, we present a cumulant expansion procedure that allows to investigate and regulate these biased estimates at different orders in baryon chemical potential μB. We find that the unbiased estimates in the cumulant expansion can truly capture the genuine higher order stochastic fluctuations of the higher order correlation functions, which got suppressed in exponential resummation. Finally, we discuss an unbiased formalism of the exponential resummation, which when expanded in form of a series, can exactly replicate the Taylor series up to a desired power in μB. This enables us to regain the knowledge of reweighting factor and most importantly, retrieve back the partition function and many of its important properties, which got entirely lost while implementing the cumulant expansion scheme. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

Item Type:	Conference Paper
Publication:	Springer Proceedings in Physics
Publisher:	Springer Science and Business Media Deutschland GmbH
Additional Information:	The copyright for this article belongs to the Springer Science and Business Media Deutschland GmbH.
Keywords:	Chemical potential; Equations of state; Expansion; Hadrons; Lattice theory; Quantum theory; Stochastic systems; Taylor series, Baryon chemical potential; Biased estimates; Cumulant expansion; Equation-of-state; Exponentials; High-order; Higher-order; Lattice QCD; Resummation; Taylor's expansion, Free energy
Department/Centre:	Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited:	10 Sep 2024 09:16
Last Modified:	10 Sep 2024 09:16
URI:	http://eprints.iisc.ac.in/id/eprint/86044

Actions (login required)

View Item