SOLVED. Sci Fi. Read in the early 2000's. Everyone in America has vanished. Set in futre of alternate-history where Nazis won. Parallel dimensions, quantum computers, virtual reality all plot points. Spoilers ahead. [s]

[Tadd]

** Potential Spoilers **
Since I'm giving all the details I remember, some of it might be considered a spoiler, but it's unintentional.

I think I read this in the early 2000's. I don't think the book was new at the time.

Everyone in America has vanished. I think the main character is tasked with finding out why. The world has become the 3rd Reich since, in this alternate reality, the Germans won WWII and conquered the world. There are some sparse comments about there not being any more Jewish people around, I think someone says "and we all know what happened to them".

There is individual space travel, I think more like stratospheric travel for quickly traversing Earth. People launch their small space-craft by accelerating over the ocean. The main character makes a quip about how annoying and controlling the German's are since they require the use of the auto-pilot during takeoff and re-entry, and he is relieved when he reaches space and can take the manual control.

The main characters enter the US in a school bus via Mexico. They find everyone gone, skeletons of infants in their cribs.

Americans had been addicted to Virtual Reality.

One of the sci-fi elements was quantum computers

**SPOILER**: In the end it is discovered that the quantum computers have a side effect of making people jump dimensions, without knowing it, explaining many anomalies that the characters acknowledge through the story.

Pulling my hair out here, I want to recommend it to someone.

Thanks for any help.

[Tadd]

Yep, still don't know what it is.

[Kris]

Tadd, is this a novel or possibly a short story in a Sci Fi anthology?

[Andy]

This is Finity, by John Barnes Finity

[Andy]

Quote from a review:

"According to Iphwin, since the introduction of quantum computing devices, every time someone uses a phone, or switches on a computer, he or she jumps into another reality, of which there are an infinite number. Iphwin himself is a human avatar of a “cyberphage,” an artificial intelligence patrolling the realities as a sort of super System Administrator. Even more puzzling, America has disappeared from every reality: just trying to think about it causes pain and confusion. "

[Andy]

The Amazon review mentions the ballistic/stratospheric travel

"Earth in 2063 is filled with intelligent cars and personal ballistic transports, but the United States has vanished from humanity's collective memory. Like everyone else, Lyle Peripart isn't even aware that he's forgotten about the U.S., until the enigmatic tycoon Geoffrey Iphwin offers him a job and tries to bring it up in conversation. "

[Andy]

This thread on ScifiStackExchange has a lot of the elements mentioned in the OP and also ids the book as Finity https://scifi.stackexchange.com/quest...

[Andy]

I dropped a line to Tadd - I really think this is Finity

[Tadd]

Hi all,

Yeah, I'm pretty sure it IS Finity. Awesome. Thanks, Andy.

[Andy]

Great! Glad to help.