The most complex sustained scientific metaphor in theater history won the Tony for Best Play in 2000, and every regional theater worth its lighting grids has been trying to illuminate it since. Now it’s Trinity Repertory Company’s turn, and each dark corner of Britisher Michael Frayn’s Copenhagen, which is heaped with tangled theories about a mysterious 1941 meeting between physicists Niels Bohr and Werner Heisenberg in the city of the title, gets enthusiastically explored.

Actually, you could treat this production like a foreign film where you get so caught up in expressive interactions that for stretches you stop checking the subtitles. Even physics phobes need have no fear. Trinity artistic director Oskar Eustis has underscored the central component in Frayn’s equation for success: though this is a play of ideas, its main engine is emotions and other felt consequences of ideas.

Copenhagen’s three characters (the third is Bohr’s wife, Margrethe) seethe and trust and shout and suspect in an orgy of arguments, recriminations, and mismatched memories till they all but collapse in a heap. Frayn, author of the impossibly convoluted yet hilarious farce Noises Off, knows full well that whether engaged people are bumping into each other or into each other’s adamant convictions, we won’t be able to take our eyes off them.

The mysterious meeting on which the play focuses was between the two formulators of the Copenhagen Interpretation of quantum mechanics, which is the theoretical underpinning of the atomic bomb. Heisenberg (Stephen Thorne), who’s the secret head of the German atomic program, is visiting his mentor, Bohr (Timothy Crowe), in his home in occupied Denmark. The play asks why Heisenberg came to Copenhagen, and it fields several competing possibilities. Was he trying to pick the brains of Bohr, Europe’s foremost expert on fission — or even recruit him? Was he trying to halt any Allied atomic-bomb work by suggesting both sides make a pact? Was he seeking absolution? Or simply bragging about his new responsibilities?

Frayn has the speculation take place after the characters’ deaths; this provides an Eternal Question perspective and facilitates shifting back and forth in time. The presence of Margrethe (Anne Scurria) induces the physicists to argue " in plain language " ; she’s also a solo Greek chorus expressing mistrust of Heisenberg’s motives.

Eustis realizes that physicalized drama can be as compelling as physical humor, so he has the actors pace like caged tigers, ranging up the aisles even when not addressing us, as they often do. Both physicists were considered reticent, but accuracy would have tuned them into PBS talking heads. So Thorne makes Heisenberg peripatetic, youthfully exuberant, as he tries to . . . what? ingratiate? win over himself, as well as the Bohrs, to the idea of his ethical innocence? (The crowning irony, of course, is that Bohr will soon escape to America and join the Manhattan Project, whereas Heisenberg, whose program failed, was never party to killing a fly.)

Crowe is convincing as an avuncular Bohr, but if he risked more gravitas and sober suspicion, he would charm us less but tighten the tension. Scurria, with fewer lines and more expressions, creates a sly proxy as she reflects our distrust and puzzlement.

And puzzlement — humbling puzzlement — is a nagging fourth character here. Heisenberg’s Uncertainty Principle doesn’t imply that we can’t be sure of anything, just that we must choose what we want to be sure about. If we measure where a particle is, we can’t know where it’s been; to choose what to observe is to decide what you can find. Frayn humbles us with that fact, and Eustis, with his carefully laid pause points, makes sure that it sinks in.

The original Michael Blakemore–directed production of Copenhagen had the audience surround the characters. Eugene Lee’s set design instead takes the physicists’ perspective: chalkboards on which they scribble equations extend across the stage, and Robert Oppenheimer’s ironically egoistic Shiva quote, " I am become death, destroyer of worlds, " glints in gold above the action. Institutional drop lights become teaching aids when Heisenberg explains quantum theory, and they extend through the audience, putting us in a lecture hall.

In 1959, British physicist and novelist C.P. Snow lamented the two conflicting, non-communicating cultures of literary intellectuals and scientists. Later he expressed hope for a third culture in which the domain of art would be " on speaking terms with the scientific one. " I don’t know how many weaponry scientists will see Copenhagen, but if this production doesn’t speak to them, we’re in big trouble.