Berry phase tagged posts

Magnetic Switch Turns Strange Quantum Property Berry Phase On and Off

These images show the orbital paths of electrons trapped within a circular region within graphene. In the classical orbit (top image), an electron that travels in a complete circuit has the same physical state as when it started on the path. However, when an applied magnetic field reaches a critical value, (bottom image), an electron completing a circuit has a different physical state its original one. The change is called a Berry phase, and the magnetic field acts as a switch to turn the Berry phase on. The result is that the electron is raised to a higher energy level. Credit: Christopher Gutiérrez, Daniel Walkup/NIST

These images show the orbital paths of electrons trapped within a circular region within graphene. In the classical orbit (top image), an electron that travels in a complete circuit has the same physical state as when it started on the path. However, when an applied magnetic field reaches a critical value, (bottom image), an electron completing a circuit has a different physical state its original one. The change is called a Berry phase, and the magnetic field acts as a switch to turn the Berry phase on. The result is that the electron is raised to a higher energy level.
Credit: Christopher Gutiérrez, Daniel Walkup/NIST

The discovery promises new insight into quantum theory and may lead to new quantum electronic devices...

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Moving Electrons around Loops with Light: A Quantum Device based on Geometry

Moving electrons around loops with light: A quantum device based on geometry

This artist’s rendition shows a laser light guiding the evolution of an electronic spin within an atomic-scale defect in diamond. These light-driven loops give rise to a geometric phase, a quantum logic operation that shows remarkable resilience to noise. Credit: Peter Allen

The quantum bit ie ‘qubit’ is represented by a vector, pointing to a simultaneous combination of the 1 and 0 states. To fully implement a qubit, it is necessary to control the direction of this qubit’s vector, which is generally done using fine-tuned and noise-isolated procedures. Researchers have demonstrated the ability to generate a quantum logic operation, or rotation of the qubit, that – surprisingly—is intrinsically resilient to noise as well as to variations in the strength or duration of the control...

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