БЛОГ

Archive for the ‘quantum physics’ category: Page 5

Jun 7, 2019

Quantum chemistry on quantum computers

Posted by in categories: chemistry, computing, particle physics, quantum physics

The special properties of quantum computers should make them ideal for accurately modelling chemical systems, Philip Ball discovers.

‘If you want to make a simulation of nature,’ the legendary physicist Richard Feynman advised in 1981, ‘you’d better make it quantum-mechanical.’ By ‘nature’, Feynman meant ‘stuff’: the particles and atoms and molecules we’re made from. His comment came in a talk published the following year, and is generally regarded as the founding text of quantum computing. It now looks even more prophetic than ever.

For although we are constantly told that the unique selling point of quantum computers is their enormous speed compared with the classical devices we currently use – a speed-up that exploits the counterintuitive laws of quantum mechanics – it seems that the most immediate benefit will be the one Feynman identified in the first place: we’ll be able to simulate nature better.

Continue reading “Quantum chemistry on quantum computers” »

Jun 7, 2019

How to build a teleportation machine: Teleportation protocol

Posted by in categories: quantum physics, time travel

I was hoping to post this earlier, but a heavy dose of writer’s block set in (I met a girl, and no, this blog didn’t help — but she is a physicist!) I also got lost in the rabbit hole that is quantum teleportation. My initial intention with this series of posts was simply to clarify common misconceptions and to introduce basic concepts in quantum information. However, while doing so, I started a whirlwind tour of deep questions in physics which become unavoidable as you think harder and deeper about quantum teleportation. I’ve only just begun this journey, but using quantum teleportation as a springboard has already led me to contemplate crazy things such as time-travel via coupling postselection with quantum teleportation and the subtleties of entanglement. In other words, quantum teleportation may not be the instantaneous Stargate style teleportation you had in mind, but it’s incredibly powerful in its own right. Personally, I think we’ve barely begun to understand the full extent of its ramifications.

Read more

Jun 7, 2019

To catch and reverse a quantum jump mid-flight

Posted by in categories: evolution, particle physics, quantum physics

In quantum physics, measurements can fundamentally yield discrete and random results. Emblematic of this feature is Bohr’s 1913 proposal of quantum jumps between two discrete energy levels of an atom. Experimentally, quantum jumps were first observed in an atomic ion driven by a weak deterministic force while under strong continuous energy measurement2,3,4. The times at which the discontinuous jump transitions occur are reputed to be fundamentally unpredictable. Despite the non-deterministic character of quantum physics, is it possible to know if a quantum jump is about to occur? Here we answer this question affirmatively: we experimentally demonstrate that the jump from the ground state to an excited state of a superconducting artificial three-level atom can be tracked as it follows a predictable ‘flight’, by monitoring the population of an auxiliary energy level coupled to the ground state. The experimental results demonstrate that the evolution of each completed jump is continuous, coherent and deterministic. We exploit these features, using real-time monitoring and feedback, to catch and reverse quantum jumps mid-flight—thus deterministically preventing their completion. Our findings, which agree with theoretical predictions essentially without adjustable parameters, support the modern quantum trajectory theory5,6,7,8,9 and should provide new ground for the exploration of real-time intervention techniques in the control of quantum systems, such as the early detection of error syndromes in quantum error correction.

Read more

Jun 7, 2019

AI Course with Sebastian Thrun and Peter Norvig: Udacity Course

Posted by in categories: biotech/medical, education, finance, quantum physics, robotics/AI

Artificial Intelligence (AI) is a field that has a long history but is still constantly and actively growing and changing. Artificial Intelligence (AI) technology is increasingly prevalent in our everyday lives. It has uses in a variety of industries from gaming, journalism/media, to finance, as well as in the state-of-the-art research fields from robotics, medical diagnosis, and quantum science.


Udacity was born out of a Stanford University experiment in which Sebastian Thrun and Peter Norvig offered their “Introduction to Artificial Intelligence” course online to anyone, for free. Over 160,000 students in more than 190 countries enrolled and not much later, Udacity was born.

Continue reading “AI Course with Sebastian Thrun and Peter Norvig: Udacity Course” »

Jun 6, 2019

Spacetime Geometry near Rotating Black Holes Acts Like Quantum Computer, Physicist Says

Posted by in categories: computing, cosmology, quantum physics

According to a theoretical paper published in the Annals of Physics, by Dr. Ovidiu Racorean from the General Direction of Information Technology in Bucharest, Romania, the geometry of spacetime around a rapidly spinning black hole (Kerr black hole) behaves like a quantum computer, and it can encode photons with quantum messages.

Read more

Jun 6, 2019

Single-spin system breaks quantum symmetry

Posted by in category: quantum physics

“Dilation” technique could allow researchers to study exotic physics in non-classical Hamiltonians.

Read more

Jun 6, 2019

How Peter Shor’s Algorithm is Destined to Put an End to Modern Encryption

Posted by in categories: computing, encryption, information science, internet, quantum physics

RSA Encryption is an essential safeguard for our online communications. It was also destined to fail even before the Internet made RSA necessary, thanks the work of Peter Shor, whose algorithm in 1994 proved quantum computers could actually be used to solve problems classical computers could not.

Read more

Jun 5, 2019

Fault-tolerant detection of a quantum error

Posted by in category: quantum physics

Noise and imperfections in a quantum system can result in the presence and propagation of errors through the system. A reliable quantum processor will need to be able to correct for these errors and error syndromes. Rosenblum et al. used higher quantum states of a superconducting-based quantum circuit to demonstrate a method for the fault-tolerant measurement of an error-correctable logical qubit. Such fault-tolerant measurements will allow more frequent interrogations of the state of the logical qubit, ultimately leading to the implementation of more quantum operations and more complex entangled quantum circuits.

Science, this issue p. 266

A critical component of any quantum error–correcting scheme is detection of errors by using an ancilla system. However, errors occurring in the ancilla can propagate onto the logical qubit, irreversibly corrupting the encoded information. We demonstrate a fault-tolerant error-detection scheme that suppresses spreading of ancilla errors by a factor of 5, while maintaining the assignment fidelity. The same method is used to prevent propagation of ancilla excitations, increasing the logical qubit dephasing time by an order of magnitude. Our approach is hardware-efficient, as it uses a single multilevel transmon ancilla and a cavity-encoded logical qubit, whose interaction is engineered in situ by using an off-resonant sideband drive. The results demonstrate that hardware-efficient approaches that exploit system-specific error models can yield advances toward fault-tolerant quantum computation.

Continue reading “Fault-tolerant detection of a quantum error” »

Jun 5, 2019

The Quatron Transistor

Posted by in categories: computing, engineering, particle physics, quantum physics

Atomic BECs were first achieved in 1995. Although it has become easier to realize atomic BECs since their discovery, they still require very low temperatures for operation. For most purposes, this is too expensive and impractical. Alternatively, negatively charged quatrons are quasi-particles composed of a hole and three electrons which form a stable BEC when coupled to light in triple quantum layer structures in semiconductor microcavities. This allows for both the greater experimental control found in quantum optics, and the benefits of matter wave systems, such as superconductivity and coherence. Moreover, due to the extremely small effective mass of the quasi-particles, quatrons can be used to achieve superconducting BECs at room temperature.


The Create the Future Design Contest was launched in 2002 by the publishers of NASA Tech Briefs magazine to help stimulate and reward engineering innovation. The annual event has attracted more than 8,000 product design ideas from engineers, entrepreneurs, and students worldwide.

Read more

Jun 5, 2019

Holographic Quantum Error Correcting Codes

Posted by in category: quantum physics

Exploring the intersection of quantum gravity in the theory of quantum error correction.

Read more

Page 5 of 220First23456789Last