An Alternative Picture of Particle Physics

All of nature springs from a handful of components — the fundamental particles — that interact with one another in only a few different ways. In the 1970s, physicists developed a set of equations describing these particles and interactions. Together, the equations formed a succinct theory now known as the Standard Model of particle physics.

The Standard Model is missing a few puzzle pieces (conspicuously absent are the putative particles that make up dark matter, those that convey the force of gravity, and an explanation for the mass of neutrinos), but it provides an extremely accurate picture of almost all other observed phenomena.

Yet for a framework that encapsulates our best understanding of nature’s fundamental order, the Standard Model still lacks a coherent visualization. Most attempts are too simple, or they ignore important interconnections or are jumbled and overwhelming.

A New Approach
Chris Quigg, a particle physicist at the Fermi National Accelerator Laboratory in Illinois, has been thinking about how to visualize the Standard Model for decades, hoping that a more powerful visual representation would help familiarize people with the known particles of nature and prompt them to think about how these particles might fit into a larger, more complete theoretical framework. 

Quigg’s visual representation shows more of the Standard Model’s underlying order and structure. He calls his scheme the “double simplex” representation, because the left-handed and right-handed particles of nature each form a simplex — a generalization of a triangle. We have adopted Quigg’s scheme and made further modifications.   READ MORE...

Quantum Computing 10 Times More Efficient

In the world of quantum error correction, an underdog is coming for the king.

Last week, new simulations from two groups reported that a rising class of quantum error-correcting codes is more efficient by an order of magnitude than the current gold standard, known as the surface code. 

The codes all work by transforming a horde of error-prone qubits into a much smaller band of “protected” qubits that rarely make mistakes. But in the two simulations, low-density parity check — or LDPC — codes could make protected qubits out of 10 to 15 times fewer raw qubits than the surface code. 

Neither group has implemented these simulated leaps in actual hardware, but the experimental blueprints suggest that these codes, or codes like them, could hasten the arrival of more capable quantum devices.

“It really looks like it’s coming to fruition,” said Daniel Gottesman of the University of Maryland, who studies LDPC codes but was not involved in the recent studies. “These [codes] could be practical things that can greatly improve our ability to make quantum computers.”

Classical computers run on bits that rarely misfire. But the particle-like objects — qubits — that power quantum computers lose their quantum mojo when just about anything jostles them out of their delicate state. 

To coax future qubits into usefulness, researchers plan to use quantum error correction, the practice of using extra qubits to redundantly encode information. It’s similar in spirit to protecting a message from static by speaking each word twice, spreading out the information among more characters.

The Canonical King
In 1998, Alexei Kitaev of the California Institute of Technology and Sergey Bravyi, then of the Landau Institute for Theoretical Physics in Russia, introduced the quantum error-correcting surface code. It organizes qubits into a square grid and executes something like a game of Minesweeper: Each qubit connects to four neighbors, so checking designated helper qubits allows you to discreetly snoop on four data-carrying qubits. 

Depending on whether the check returns a 0 or a 1, you can infer whether some of the neighbors have erred. By checking around the board, you can deduce where the errors are and fix them.  READ MORE...