Jeff Cassman

Eugenio Calabi was known to his colleagues as an inventive mathematician — “transformatively original,” as his former student Xiuxiong Chen put it. In 1953, Calabi began to contemplate a class of shapes that nobody had ever envisioned before. Other mathematicians thought their existence was impossible. But a couple of decades later, these same shapes became… Continue reading The Mathematician Who Shaped String Theory

Finding Factors Quantum computers derive their power from the peculiar way they process information. Classical computers use bits, each of which must always be in one of two states, labeled 0 and 1. Quantum bits, or “qubits,” can additionally be in combinations of their 0 and 1 states — a phenomenon called superposition. It’s also… Continue reading Thirty Years Later, a Speed Boost for Quantum Factoring

A brain is nothing if not communicative. Neurons are the chatterboxes of this conversational organ, and they speak with one another by exchanging pulses of electricity using chemical messengers called neurotransmitters. By repeating this process billions of times per second, a brain converts clusters of chemicals into coordinated actions, memories and thoughts. Researchers study how… Continue reading These Cells Spark Electricity in the Brain. They’re Not Neurons.

In other words, he showed that an entanglement-free quantum circuit was easy to simulate on a classical computer. In a computational sense, the circuit wasn’t intrinsically quantum. The collection of all such non-entangling circuits (or, equivalently, all arrangements of qubits that might come out of these non-entangling circuits) formed something of a classically simulable island… Continue reading The Quest to Quantify Quantumness