When I need to concentrate, I listen to Bach's Cello Suites, a set of pieces written for a solo cello about three hundred years ago. I'm doing a PhD in chemistry in Leeds, and I'm originally from Lahore, so I spend an enormous amount of time writing and analysing data.
I started listening to them during my master's degree, when I was writing my thesis in a very noisy shared house. I'd tried pop music, but I found myself singing along and losing focus. Then my supervisor, Dr Evans, mentioned that he always wrote papers listening to the Cello Suites, so I tried a recording one evening and it just clicked. I've used them ever since, so that's about four years now.
I usually listen through noise-cancelling headphones, at quite a low volume. There are six suites, and together they last around two hours, which is conveniently the length of a good work session. When the last suite finishes, I know it's time for a break.
I think it helps me concentrate for a few reasons. Firstly, there are no words, so there's nothing competing with the words I'm reading or writing. Secondly, it's one instrument, so it's calm but not boring. The music moves forward steadily, almost like a person walking, and somehow it carries my thinking along with it. And thirdly, it's become a kind of signal. Because I only play it when I work, as soon as the first notes start, my brain seems to switch into work mode. My friends think it's a strange choice for someone my age, but it's become an essential part of my routine.