History is replete with tales of scientists behaving badly, particularly when one of them dares to challenge the theories of another. Faraday battled with Ampère about the finer points of electromagnetic theory. Einstein sharply disagreed with his colleagues about the emerging field of quantum mechanics, famously declaring that “God does not play dice with the universe”. And Newton fought with everybody, including Huygens, Hooke, Flamsteed and, of course, Leibniz.

Readers who do not understand the passionate intensity of scientific arguments may find the events in Juli Zeh’s novel Dark Matter perplexing. But those who do will feel an instant affinity for the book’s central characters Sebastian and Oskar, two physicists who “were said to love physics even more than they loved each other, and [who] fought over it with the passion of rivals”. As their story shows, the opposite of love is not hate; it is indifference. Unfortunately, their shared intellectual love affair takes a destructive turn that reverberates throughout the narrative.

Zeh tells her story in bits and pieces, allowing these to accumulate slowly until they form a dazzling whole. In the beginning, we see two lifelong friends bitterly debating the philosophical implications of a physics theory that invokes the possibility of parallel worlds. Then a young boy is kidnapped and a diabolical ransom demanded. An anaesthesiologist meets a grisly end. A loyal wife loses faith in her husband. A scientist’s carefully structured life unravels. And eventually an unorthodox detective with a love of physics and an inoperable brain tumour steps in to solve his final case by connecting these seemingly random events.

A bestseller in Germany when it first appeared in 2007 under the title Schilf, this new English translation of Dark Matter (published as In Free Fall in the US) follows in the footsteps of other novels by authors who have found inspiration in esoteric physics, notably Jeannette Winterson’s Gut Symmetries and Jonathan Lethem’s As She Crawled Across the Table. But where Winterson embraced string theory and Lethem mined the mother lode of wormholes and extra dimensions, Zeh finds her muse in the “many worlds” interpretation of quantum mechanics.

First proposed in the 1950s by the physicist Hugh Everett III, the premise of the controversial “many worlds” hypothesis is straightforward enough. In any quantum system, every possible outcome for an experiment is present simultaneously in a superposition of states. The sum of all those outcomes is described by the wavefunction. It is only when we observe the system by making a measurement that the wavefunction collapses and all of those possibilities reduce to a single “real” event: the outcome of our observation.

But what happens to those other possibilities once the wavefunction has collapsed? The strictest interpretation of quantum theory simply assumes that by necessity all the other potential outcomes vanish once a measurement is made. Everett offered an alternative: perhaps the wavefunction continues to evolve, forever splitting into other wavefunctions in a never-ending tree, with every branch becoming an entire universe. In this way, every potential outcome contained in the wavefunction – a photon appearing as a particle or wave; a boy being kidnapped or not kidnapped – is realized in its own separate universe. Perhaps, as Sebastian puts it, “Everything that is possible happens.”

In Zeh’s novel, “many worlds” becomes a richly complex metaphor for regret over the road not taken. As in physics, so in life: our choices collapse our wavefunction and set us on a certain course. Sebastian’s wife, Maike, exists in a nebulous superposition of states until one day she meets her future husband on the street and her wavefunction collapses into marriage and motherhood. But perhaps there exists a parallel universe where she made a different choice, with a very different outcome.

Dark Matter is filled with split universes. Inseparable back in their university days, Sebastian quarrels with Oskar out of jealousy, and their personal and professional paths diverge. Yet even though he has chosen a rather sedate, traditional life as a happily married academic, Sebastian is filled with regret at what he has lost: those heady, passionate early days with Oskar, his intellectual soul mate. He clings to the notion of many worlds, reasoning that “[T]here must be other universes in which things went differently… In which Oskar [and I] would never lose each other.”

For his part, Oskar is equally bent on forcing his friend to confront the reality of the break, with an eye toward winning him back. It is a strategy with tragic consequences. But by far the most compelling character is Detective Schilf, whose world diverged into “before” and “after” following the loss of his wife and child. And now his mind is splitting, too, thanks to a brain tumour that he nicknames “the Observer”.

Zeh skilfully pulls together these disparate threads into a compelling intellectual thriller, in which the “villain” turns out to be as mysteriously elusive as the quantum theory of gravity Oskar pursues so single-mindedly. She only stumbles once, with the inexplicable inclusion of a ham-fisted chapter that consists of little more than Sebastian’s monologue detailing his thoughts about time, causality, coincidence, free will and the multiverse. It is overly didactic and jolts the reader out of the story just as the narrative reaches its climax. Zeh’s prose is most effective when she lets her big ideas lurk in the background, rather than take centre stage.

That quibble aside, Dark Matter admirably showcases Zeh’s meticulous plotting, skilful foreshadowing and lyrical turns of phrase; Christine Lo’s translation is sparsely elegant. Perhaps in a different novel, the motives of Zeh’s characters, and their wildly irrational responses to events as they unfold, would strike the reader as highly improbable, straining the willing suspension of disbelief to a breaking point. But in a fictional world where “everything that is possible happens”, these are just other branches in the wavefunction.