NEW YORK — Don’t be frightened off by the title of the Broadway play “Heisenberg.” There’s no need to brush up on any quantum physics or mathematical inequalities. All you need to know is a simple idea: The whole is more than the sum of its parts.

“Heisenberg” is as stripped down as theater can get — two chairs, two tables, two actors, one slender script. But Simon Stephens’ play also is as sumptuous an experience as theater gets.

Quirky, lovely, funny, powerful and special, “Heisenberg” opened Thursday at the Samuel J. Friedman Theatre starring Mary-Louise Parker and Denis Arndt as unconventional lovers who, it turns out, might be perfect for each other.

Whether this fragile play would successfully make the leap from its perch at a 150-seat off-Broadway space where it made its debut last year to its new home in a 660-seat Broadway theater was a big question.

Have no fear: Director Mark Brokaw upped the intimacy level by putting bleacher seats on much of the stage, making the venue into a poor man’s theater-in-the-round. Then he let Parker and Arndt do what they do best.

In the play, babble-mouthed 42-year-old Georgie from New Jersey randomly meets a bored 75-year-old Irish butcher, Alex, in a London train station and the two begin a strange courtship. Georgie reveals she is somewhat broken and Alex must endure plenty of lies before the real Georgie is revealed.

Both are lonely souls and Georgie benefits from Alex’s quiet patience, while Alex comes alive with fresh wonder around Georgie. Their age gap is commented on, but not as important as you might think.

Stephens sides with love — in whatever way it comes — and he embraces human mutability. Of personalities, Alex says: “They’re never fixed. They can always change. They mean nothing.” Later, he turns to Georgie: “We hold very different perspectives on experiences we imagine we’re sharing, don’t we?”

The title comes from a strange aspect of quantum physics called the Heisenberg Uncertainty Principle, which says it is impossible to measure both the speed and position of an object at the same time.

Georgie nicely reduces it down to this: “If you watch something closely enough you realize you have no possible way of telling where it’s going or how fast it’s getting there.” It fits naturally into a script that celebrates randomness and predictability.

Stephens, who adapted “The Curious Incident of the Dog in the Night-Time” for the stage, does nothing less than alchemy here. He captures new love and old love at the same time, hope and fear, the new world and the old. He’s turned the simplest of tales — boy meets girl — into an unexpectedly rich thing with just two chairs, two tables and two actors.


Mark Kennedy on Twitter at