Measuring the speed of sound in matter created in heavy-ion collisions

Heavy-ion collision experiments offer a unique opportunity to study the properties of hot and dense nuclear matter in a laboratory. In particular, many current analyses are directed towards uncovering the phase diagram of QCD. In these studies, enhanced fluctuations of baryon number are given considerable attention as possible signatures of the QCD critical point. In this talk, I will show that using fluctuations in the number of detected particles may also allow one to measure a fundamental characteristic of the studied systems: the speed of sound and its logarithmic derivative with respect to the baryon number density. I will discuss what we might learn from existing data and what remains to be done to connect experimental results with properties of dense QCD matter.