“Of course you can,” he offers. “Consider where we are.”

“Switzerland.”

“Meyrin, Switzerland,” he specifies.

“The Large Hadron Collider,” she realizes aloud, the words tumbling out in a whisper.

He points at her—exactly—before saying, “My body is now suffused with quantum energy. The process essentially unanchored me from my reality, allowing me to slip into yours.”

Her beer bottle empty, Eva—saucer eyed—reaches forward to drain Jonas’s. “If that’s true”—Jonas can see her mind grasping—“then why aren’t you continuing to . . . ‘slip,’ to use your word? What keeps you in this reality?” But she doesn’t wait for Jonas to answer as her understanding gains momentum. “In fact, what’s to keep you from slipping realities forever?”

“This.” Jonas holds up his hand, showing her his ring. “I call it my ‘tether.’ It’s the only piece of nonorganic matter that can make the trip with me.”

“Nonorganic?”

“Anything synthetic,” Jonas confirms. “I even had to have my fillings taken out and replaced with silver.”

“But why?” she asks.

“Remember, we’re dealing with radiation, essentially. Quantum radiation, yes, but still. Different types of matter absorb and retain radiation differently. When I first started out, all my computer models were . . .” He searches for the word.

“Totally wack?” Eva offers.

“To use the technical term.” This time, they both share a smile. A moment. “In any case, the model results changed when I only factored in organic materials.”

“Except for your ‘tether.’”

Jonas points to it, resting on his finger. “It’s different from everything else because it’s regulating the radiation in question. As long as I’m wearing it, I’m rooted in whichever universe I’m standing in.”

“And if you take it off?”

Jonas flutters his hand upward, fingers wagging. “I move through universes like a feather on the wind.”

“And, what, you land when you put it back on?”

“Actually, it takes a universe or two to settle.”

“Settle?”

“Like a roulette wheel slowly coming to a complete stop.”

Eva furrows her brow. Taking all this in. Turning it over in her mind, examining the whole impossible, incredible situation from all available angles.

“You’re taking this all very well,” Jonas observes.

Eva barely acknowledges the compliment, still thinking, still probing. “What about your clothes? Paul didn’t mention you showing up naked.”

Jonas plucks at his shirt. “All-natural fibers and materials. Even my shoes.”

“So you’re not carrying any money,” she notes.

“Good point. You’re going to have to pay for our drinks.” They share another flash of connection even in the face of a conversation that seems, at best, on the outer edge of sanity.

“So, your tattoo . . .”

Jonas rolls up his sleeve, turning out his forearm. “The collider needed to be calibrated very precisely.”

“I’d imagine.”

“I couldn’t chance leaving all this to memory, and I needed a way to bring my notes, my calculations, with me. I considered keeping them on cotton parchment, writing with something like squid ink, but that would mean risking losing the formulae, so I employed the obvious solution.”

Eva’s gaze flits across the tattoo. Once again, her eyes spark at the Schrödinger equation at the center of the calculations, the cornerstone of the Many Worlds Theory. “If the Jonas Cullen of . . . of my universe wasn’t a Nobel-winning scientist, I don’t think I’d believe any of this.”

Jonas smiles inwardly, taking some small measure of pride in being a Nobel winner in at least two universes. “What did I win for?” he can’t help but ask.

Eva winces, searching her memory. “Something about the control of particles in entangled states?” she grasps. “But forget about that a second.”

“Forget about winning a Nobel Prize? Sure. No problem.”

“I’m serious,” she insists. “This is serious. I have to ask . . .” She pauses, measuring her next words. “I just . . . I don’t understand why you’d go through all that trouble. I mean, you were risking your life to travel to a reality where you and your wife are both dead.”

Jonas breathes out a sigh. “You strike me as much smarter than that, Dr. Stamper.”

“You’re lost.” The conclusion escapes her in a breath. The conspicuous answer, present all along.

Jonas runs a finger along his tattoo, across the arcane mélange of letters and numbers and symbols, feeling like they have betrayed him. “I thought I’d correctly determined how the LHC needed to be calibrated in order to arrive at the universe where Amanda’s still alive.”

“And how does that work, exactly?”

“It’s highly technical,” he demurs.

“Really?” she says sarcastically. “That’s almost hard to imagine.”

Jonas leans forward and parts his hands. Okay. I’ll play. “I altered the Large Hadron Collider so that it would leak out a small amount of quantum radiation. Radiation is nothing more than the emission of energy in the form of waves. Waves have frequencies. Change the frequency, and you alter the quality of the radiation. Alter the quality of the radiation, and you change the effect it has on the cells of the human body. In this case, mine.”

Eva shakes her head. “I’m afraid you lost me.”

“I did warn you,” he chides playfully.

“Yes, you did.” He catches her staring at him. There’s no mistaking the look on her face as attraction, but Jonas compels himself not to dwell on it.

“Bottom line, I intended to use the quantum radiation to untether myself from my home reality, but in a very specific way. Think of it like letting go of a helium balloon with the intention that it floats up through a skylight.”

“And this theoretical ‘skylight’ leads to a reality where your wife is still alive.”

Jonas feels a pang of disappointment. “I thought I’d located a reality where Amanda was still alive and I wasn’t. Clearly, something was lacking in my calculations, because I originally ended up in a reality where she was already dead.”

Eva seems confused. “Originally?”