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Archive for the ‘mathematics’ category: Page 116

Aug 11, 2020

Time-reversal of an unknown quantum state

Posted by in categories: computing, engineering, information science, mathematics, quantum physics

Physicists have long sought to understand the irreversibility of the surrounding world and have credited its emergence to the time-symmetric, fundamental laws of physics. According to quantum mechanics, the final irreversibility of conceptual time reversal requires extremely intricate and implausible scenarios that are unlikely to spontaneously occur in nature. Physicists had previously shown that while time-reversibility is exponentially improbable in a natural environment—it is possible to design an algorithm to artificially reverse a time arrow to a known or given state within an IBM quantum computer. However, this version of the reversed arrow-of-time only embraced a known quantum state and is therefore compared to the quantum version of pressing rewind on a video to “reverse the flow of time.”

In a new report now published in Communications Physics, Physicists A.V. Lebedev and V.M. Vinokur and colleagues in materials, physics and advanced engineering in the U.S. and Russia, built on their previous work to develop a technical method to reverse the temporal evolution of an arbitrary unknown . The technical work will open new routes for general universal algorithms to send the temporal evolution of an arbitrary system backward in time. This work only outlined the mathematical process of time reversal without experimental implementations.

Aug 5, 2020

The mathematician who helped to reshape physics

Posted by in categories: mathematics, physics

Barry Simon linked a phenomenon that had shocked physicists to topology, the branch of mathematics that studies shapes.

Aug 4, 2020

Casimir force used to control and manipulate objects

Posted by in categories: computing, mathematics, quantum physics

A collaboration between researchers from the University of Western Australia and the University of California Merced has provided a new way to measure tiny forces and use them to control objects.

The research, published today in Nature Physics, was jointly led by Professor Michael Tobar, from UWA’s School of Physics, Mathematics and Computing and Chief Investigator at the Australian Research Council Centre of Excellence for Engineered Quantum Systems and Dr. Jacob Pate from the University of Merced.

Professor Tobar said that the result is a new way to manipulate and control in a non-contacting way, allowing enhanced sensitivity without adding loss.

Aug 1, 2020

Did Scientists Actually Spot Evidence Of Another Universe?

Posted by in categories: cosmology, mathematics, physics

In a study published earlier this month, a team of theoretical physicists is claiming to have discovered the remnants of previous universes hidden within the leftover radiation from the Big Bang. Our universe is a vast collection of observable matter, like gas, dust, stars, etc., in addition to the ever-elusive dark matter and dark energy. In some sense, this universe is all we know, and even then, we can only directly study about 5% of it, leaving 95% a mystery that scientists are actively working to solve. However, this group of physicists is arguing that our universe isn’t alone; it’s just one in a long line of universes that are born, grow, and die. Among these scientists is mathematical physicist Roger Penrose, who worked closely with Stephen Hawking and currently is the Emeritus Rouse Ball Professor of Mathematics at Oxford University. Penrose and his collaborators follow a cosmological theory called conformal cyclic cosmology (CCC) in which universes, much like human beings, come into existence, expand, and then perish.

Jul 30, 2020

The Two Forms of Mathematical Beauty

Posted by in categories: mathematics, space

Mathematicians typically appreciate either generic or exceptional beauty in their work, but one type is more useful in describing the universe.

Jul 30, 2020

How Physics Found a Geometric Structure for Math to Play With

Posted by in categories: mathematics, physics

Symplectic geometry is a relatively new field with implications for much of modern mathematics. Here’s what it’s all about.

Jul 29, 2020

The quantum Hall effect continues to reveal its secrets to mathematicians and physicists

Posted by in categories: mathematics, quantum physics

A transformative experiment is yielding fresh insights 40 years after the effect’s discovery — and energizing transdisciplinary collaborations.

Jul 28, 2020

Man creates new Led Zeppelin song using the power of artificial intelligence

Posted by in categories: mathematics, robotics/AI

There have been many landmarks in the history of artificial intelligence, from the formulation of the mathematical theory that inspired neural networks back in 1943, to IBM’s famous Watson AI beating two champion Jeopardy! contestants in 2011 to win a million dollar prize.

Future historians may look back at 2020 as a similarly important checkpoint on the road to AI dominance. Why? Because YouTuber Funk Turkey has created a new Led Zeppelin song using the power of AI.

Jul 23, 2020

Scientists discover a topological magnet that exhibits exotic quantum effects

Posted by in categories: engineering, mathematics, quantum physics

An international team led by researchers at Princeton University has uncovered a new class of magnet that exhibits novel quantum effects that extend to room temperature.

The researchers discovered a quantized topological phase in a pristine magnet. Their findings provide insights into a 30-year-old theory of how electrons spontaneously quantize and demonstrate a proof-of-principle method to discover new topological magnets. Quantum magnets are promising platforms for dissipationless current, high storage capacity and future green technologies. The study was published in the journal Nature this week.

The discovery’s roots lie in the workings of the quantum Hall effect- a form of topological effect which was the subject of the Nobel Prize in Physics in 1985. This was the first time that a branch of theoretical mathematics, called topology, would start to fundamentally change how we describe and classify matter that makes up the world around us. Ever since, topological phases have been intensely studied in science and engineering. Many new classes of quantum materials with topological electronic structures have been found, including topological insulators and Weyl semimetals. However, while some of the most exciting theoretical ideas require , most materials explored have been nonmagnetic and show no quantization, leaving many tantalizing possibilities unfulfilled.

Jul 21, 2020

Temporal aiming with temporal metamaterials

Posted by in categories: mathematics, physics, space travel

Tailoring and manipulating electromagnetic wave propagation has been of great interest within the scientific community for many decades. In this context, wave propagation has been engineered by properly introducing spatial inhomogeneities along the path where the wave is traveling. Antennas and communications systems in general have greatly benefited from this wave-matter control. For instance, if one needs to re-direct the radiated field (information) from an antenna (transmitter) to a desired direction and reach a receiving antenna placed at a different location, one can simply place the former in a translation stage and mechanically steer the propagation of the emitted electromagnetic wave.

Such beam steering techniques have greatly contributed to the spatial aiming of targets in applications such as radars and point-to-point communication systems. Beam steering can also be achieved using metamaterials and metasurfaces by means of spatially controlling the effective electromagnetic parameters of a designed meta-lens antenna system and/or using reconfigurable meta-surfaces. The next question to ask: Could we push the limits of current beam steering applications by controlling electromagnetic properties of media not only in space but also in time (i.e., 4D metamaterials x, y,z, t)? In order words, would it be possible to achieve temporal aiming of electromagnetic waves?

In a new paper published in Light Science & Applications, Victor Pacheco-Peña from the School of Mathematics, Statistics and Physics of Newcastle University in UK and Nader Engheta from and Department of Electrical and Systems Engineering of the University of Pennsylvania, USA have answered this question by proposing the idea of temporal metamaterials that change from an isotropic to an anisotropic permittivity tensor. In this concept, the authors consider a rapid change of the permittivity of the whole medium where the wave is traveling and demonstrated both numerically and analytically the effects of such a temporal boundary caused by the rapid temporal change of permittivity. In so doing, forward and backward waves are produced with wave vector k preserved through the whole process while frequency is changed, depending on the values of the permittivity tensor before and after the temporal change of permittivity.