New approach to the quantum measurement problem

Quantum mechanics is a probabilistic theory that does not describe individual events. Yet when we perform a single measurement, we find a well-defined outcome. This apparent contradiction, known as the measurement problem, has a long history going back to the early days of quantum mechanics. A research collaboration proposes a new approach to this problem.

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Evolution Runs Faster on Short Timescales

Examine evolution over the course of years or centuries, and you’ll find that it progresses much more quickly than it does over geologic time. …

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Ultrashort light pulses for fast ‘lightwave’ computers

Extremely short, configurable ‘femtosecond’ pulses of light demonstrated by an international team could lead to future computers that run up to 100,000 times faster than today’s electronics.

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Solution: ‘Taming Quantum Weirdness’

A simple analogue could offer insights into one of the most astonishing results of quantum mechanics. …

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Single atom memory: The world’s smallest storage medium

One bit of digital information can now be successfully stored in an individual atom. This result is a breakthrough in the miniaturization of storage media and has the potential to serve as a basis for quantum computing.

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‘Blurred times’ in a quantum world

When measuring time, we normally assume that clocks do not affect space and time, and that time can be measured with infinite accuracy at nearby points in space. Combining quantum mechanics and Einstein’s theory of general relativity theoretical physicists have demonstrated a fundamental limitation for our ability to measure time. The more precise a given clock is, the more it ‘blurs’ the flow of time measured by neighboring clocks.

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Estimating the fidelity of T gates using standard interleaved randomized benchmarking

Randomized benchmarking is an important protocol for robustly characterizing the error rates of quantum gates. The technique is typically applied to the Clifford gates since they form a group that satisfies a convenient technical condition of forming a unitary 2-design, in addition to having a tight connection to fault-tolerant quantum computing and an efficient classical simulation. In order to achieve universal quantum computing one must add at least one additional gate such as the T gate (also known as the π /8 gate). Here we propose and analyze a simple variation of the standard interleaved RB protocol that can accurately estimate the average fidelity of the T gate while retaining the many advantages of a unitary 2-design and the fidelity guarantees that such a design delivers, as well as the efficient classical simulation property of the Clifford group. Our work complements prior methods that have succeeded in estimating T gate fidelities, but onl… …

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Scientists create new form of matter, a time crystal

Scientists are reporting on the creation of a phase of matter, dubbed a time crystal, in which atoms move in a pattern that repeats in time rather than in space.

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