Jul 28, 2022 02:20 AM
https://www.scientificamerican.com/artic...dimension/
EXCERPT: . . . Opening a portal to an extra time dimension—even just a theoretical one—sounds thrilling, but it was not the physicists’ original plan. “We were very much motivated to see what new types of phases could be created,” says study co-author Andrew Potter, a quantum physicist at the University of British Columbia. Only after envisioning their proposed new phase did the team members realize it could help protect data being processed in quantum computers from errors.
Standard classical computers encode information as strings of bits—0’s or 1’s—while the predicted power of quantum computers derives from the ability of quantum bits, or qubits, to store values of either 0 or 1, or both simultaneously (think Schrödinger’s cat, which can be both dead and alive). Most quantum computers encode information in the state of each qubit, for instance in an internal quantum property of a particle called spin, which can point up or down, corresponding to a 0 or 1, or both at the same time. But any noise—a stray magnetic field, say—could wreak havoc on a carefully prepared system by flipping spins willy-nilly and even destroying quantum effects entirely, thereby halting calculations.
Potter likens this vulnerability to conveying a message using pieces of string, with each string arranged in the shape of an individual letter and laid out on the floor. “You could read it fine until a small breeze comes along and blows a letter away,” he says. To create the more error-proof quantum material, Potter’s team looked to topological phases. In a quantum computer that exploits topology, information is not encoded locally in the state of each qubit but is woven across the material globally. “It’s like a knot that’s hard to undo—like quipu,” the Incas’ mechanism for storing census and other data, Potter says.
“Topological phases are intriguing because they offer a way to protect against errors that’s built into the material,” adds study co-author Justin Bohnet, a quantum physicist at the company Quantinuum in Broomfield, Colo., where the experiments were carried out. “This is different to traditional error-correcting protocols, where you are constantly doing measurements on a small piece of the system to check if errors are there and then going in and correcting them.”
Quantinuum’s H1 quantum processor is made up of a strand of 10 qubits—10 ytterbium ions—in a vacuum chamber, with lasers tightly controlling their positions and states. Such an “ion trap” is a standard technique used by physicists to manipulate ions. In their first attempt to create a topological phase that would be stable against errors. . . (MORE - missing details)
EXCERPT: . . . Opening a portal to an extra time dimension—even just a theoretical one—sounds thrilling, but it was not the physicists’ original plan. “We were very much motivated to see what new types of phases could be created,” says study co-author Andrew Potter, a quantum physicist at the University of British Columbia. Only after envisioning their proposed new phase did the team members realize it could help protect data being processed in quantum computers from errors.
Standard classical computers encode information as strings of bits—0’s or 1’s—while the predicted power of quantum computers derives from the ability of quantum bits, or qubits, to store values of either 0 or 1, or both simultaneously (think Schrödinger’s cat, which can be both dead and alive). Most quantum computers encode information in the state of each qubit, for instance in an internal quantum property of a particle called spin, which can point up or down, corresponding to a 0 or 1, or both at the same time. But any noise—a stray magnetic field, say—could wreak havoc on a carefully prepared system by flipping spins willy-nilly and even destroying quantum effects entirely, thereby halting calculations.
Potter likens this vulnerability to conveying a message using pieces of string, with each string arranged in the shape of an individual letter and laid out on the floor. “You could read it fine until a small breeze comes along and blows a letter away,” he says. To create the more error-proof quantum material, Potter’s team looked to topological phases. In a quantum computer that exploits topology, information is not encoded locally in the state of each qubit but is woven across the material globally. “It’s like a knot that’s hard to undo—like quipu,” the Incas’ mechanism for storing census and other data, Potter says.
“Topological phases are intriguing because they offer a way to protect against errors that’s built into the material,” adds study co-author Justin Bohnet, a quantum physicist at the company Quantinuum in Broomfield, Colo., where the experiments were carried out. “This is different to traditional error-correcting protocols, where you are constantly doing measurements on a small piece of the system to check if errors are there and then going in and correcting them.”
Quantinuum’s H1 quantum processor is made up of a strand of 10 qubits—10 ytterbium ions—in a vacuum chamber, with lasers tightly controlling their positions and states. Such an “ion trap” is a standard technique used by physicists to manipulate ions. In their first attempt to create a topological phase that would be stable against errors. . . (MORE - missing details)