Quantum Complex Matter 2020 will be held in, Rome - Italy at the Bruno Touschek Congress Center Frascati National Laboratories LNF of Istituto Nazionale di Fisica Nucleare (Tor Vergata) which can be reached in 18 minutes from Central railroad Station of Rome (Roma Termini).

You can get detailed information how to reach Frascati Laboratories on the web site

HOW TO REACH the Laboratori Nazionali di Frascati by train from Termini Station in Rome ?
Take a train in "Roma Termini" station going to the "Tor Vergata" railroad station as you can see on the web site:

Frascati Laboratory INFN (Quantum Complex Matter CONFERENCE SITE) is a walking distance from the exit of Tor Vergata railroad station

HOW TO REACH Frascati hotels ?
Hotels located in Frascati downtown could be close to Frascati main railroad station
Hotels located in Frascati downtown are very far from Tor Vergata Station
Conference Hotels located in Frascati could provide a shuttle to the Frascati LNF Laboratories