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Category: quantum physics – Page 921

String Theory’s Weirdest Ideas Finally Make Sense—Thanks to VR

The robot is building a tesseract. He motions at a glowing cube floating before him, and an identical cube emerges. He drags it to the left, but the two cubes stay connected, strung together by glowing lines radiating from their corners. The robot lowers its hands, and the cubes coalesce into a single shape—with 24 square faces, 16 vertices, and eight connected cubes existing in four dimensions. A tesseract.

This isn’t a video game. It’s a classroom. And the robot is Brian Greene, a physicist at Columbia University and bestselling author of several popular science books. His robot avatar teaches a semicircle of student robots, each wearing a shoulder badge of their home country’s flag. The classroom is outer space: Greene and the arc of student-robots orbit Earth. After he shows the students the tesseract, Greene directs his class to try making four, five, even six dimension objects. This is a virtual reality course on string theory; the lesson happens to be about objects with more than three dimensions.

In real life, Greene is wearing a dark blue shirt, black jeans, and boots, and his normal, non-hovering chair is sitting in a concrete-floored VR business called Step Into the Light planted firmly on Earth’s surface—Manhattan’s Lower East Side. An HTC Vive headset covers his face, and he gestures effusively—he’s a New York native—with the controllers.

Scientists Have an Experiment to See If the Human Mind Is Bound to the Physical World

Theoretical physicist Lucien Hardy is pushing wants to push the boundaries of quantum physics by performing a Bell test using humans as links. This could potentially shed light on the existence of human consciousness and just what it is made of.

Perhaps one of the most intriguing and interesting phenomena in quantum physics is what Einstein referred to as a “spooky action at a distance” — also known as quantum entanglement. This quantum effect is behind what makes quantum computers work, as quantum bits (qubits) generally rely on entanglement to process data and information. It’s also the working theory behind the possibility of quantum teleportation.

Scientists discover all quantum particles can travel BACKWARD

In the study, researchers from the Universities of York, Munich, and Cardiff explored the phenomenon known as backflow in particles that are not ‘free.’

Free quantum particles exist without any external forces, but the researchers note that this setting is idealized.

Through the new analysis, the researchers estimated the strength of backflow and found that it applies to all quantum particles, not just free ones.

Pushing Particles Forwards Might Make Them Go Backwards Because Quantum Physics Is Bonkers

You are very lucky that you ended up about the size that you are today, somewhere between one and ten feet tall and weighing somewhere between one and one thousand pounds. This is a very good size. Not to body shame, but if you were, say, a quadrillion times shorter and weighed a nonillion times less (that’s one followed by 30 zeros), that would be very inconvenient for you. Everything would be very inconvenient for you.

One thing you take for granted as a human-sized thing, for example, is that when you push things, they move forward. But a team of researchers realized that this is not necessarily the case if you zoom into the quantum world, where particles might decide to go backwards, no matter what kind of outside force you put on them.

Scientists Just Teleported a Photon from Earth to Orbit for the First Time

Researchers from China successfully teleported a photon from Earth to a satellite 500 km away. The work is an essential step towards establishing a global-scale quantum internet.

Not long ago, in the early 1990s, scientists only speculated that teleportation using quantum physics could be possible. Since then, the process has become a standard operation in quantum optics labs around the world. In fact, just last year, two separate teams conducted the world’s first quantum teleportation outside of a laboratory.

Quantum back-action-evading measurement of motion in a negative mass reference frame

Interesting…

Quantum mechanics dictates that a continuous measurement of the position of an object imposes a random quantum back-action (QBA) perturbation on its momentum. This randomness translates with time into position uncertainty, thus leading to the well known uncertainty on the measurement of motion1, 2. As a consequence of this randomness, and in accordance with the Heisenberg uncertainty principle, the QBA3, 4 puts a limitation—the so-called standard quantum limit—on the precision of sensing of position, velocity and acceleration. Here we show that QBA on a macroscopic mechanical oscillator can be evaded if the measurement of motion is conducted in the reference frame of an atomic spin oscillator6, 7. The collective quantum measurement on this hybrid system of two distant and disparate oscillators is performed with light. The mechanical oscillator is a vibrational ‘drum’ mode of a millimetre-sized dielectric membrane, and the spin oscillator is an atomic ensemble in a magnetic field9, 10. The spin oriented along the field corresponds to an energetically inverted spin population and realizes a negative-effective-mass oscillator, while the opposite orientation corresponds to an oscillator with positive effective mass. The QBA is suppressed by −1.8 decibels in the negative-mass setting and enhanced by 2.4 decibels in the positive-mass case. This hybrid quantum system paves the way to entanglement generation and distant quantum communication between mechanical and spin systems and to sensing of force, motion and gravity beyond the standard quantum limit.

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