Lifeboat Foundation

As hardware makers continue to work on ways of making wide-scale quantum computing a reality, a startup out of Australia that is building software to help reduce noise and errors on quantum computing machines has raised a round of funding to fuel its U.S. expansion.

Q-CTRL is designing firmware for computers and other machines (such as quantum sensors) that perform quantum calculations, firmware to identify the potential for errors to make the machines more resistant and able to stay working for longer (the Q in its name is a reference to qubits, the basic building block of quantum computing).

The startup is today announcing that it has raised $15 million, money that it plans to use to double its team (currently numbering 25) and set up shop on the West Coast, specifically Los Angeles.

Machine learning techniques have so far proved to be very promising for the analysis of data in several fields, with many potential applications. However, researchers have found that applying these methods to quantum physics problems is far more challenging due to the exponential complexity of many-body systems.

The fabric of space-time may get its robustness from a network of quantum particles, according to a principle called quantum error correction.

There are many different ways to think about probability. Quantum mechanics embodies them all.

Physicists are trying to rewrite the axioms of quantum theory from scratch in an effort to understand what it all means. The problem? They’ve been almost too successful.

Abstract: In this review-article, we discuss the consequences of the introduction of a quantum of time tau_0 in the formalism of non-relativistic quantum mechanics (QM) by referring ourselves in particular to the theory of the “chronon” as proposed by P.Caldirola. Such an interesting “finite difference” theory, forwards —at the classical level— a solution for the motion of a particle endowed with a non-negligible charge in an external electromagnetic field, overcoming all the known difficulties met by Abraham-Lorentz’s and Dirac’s approaches (and even allowing a clear answer to the question whether a free falling charged particle does or does not emit radiation), and —at the quantum level— yields a remarkable mass spectrum for leptons. After having briefly reviewed Caldirola’s approach, we compare one another the new Schroedinger, Heisenberg and density-operator (Liouville-von Neumann) pictures resulting from it. Moreover, for each representation, three (retarded, symmetric and advanced) formulations are possible, which refer either to times t and t-tau_0, or to times t-tau_0/2 and t+tau_0/2, or to times t and t+tau_0, respectively. It is interesting to notice that, e.g., the “retarded” QM does naturally appear to describe QM with friction, i.e., to describe dissipative quantum systems (like a particle moving in an absorbing medium). In this sense, discretized QM is much richer than the ordinary one. When the density matrix formalism is applied to the solution of the measurement problem in QM, very interesting results are met, so as a natural explication of “decoherence”.

From: [view email].

PDF | The introduction of quantum of time, called Chronon, and its consequences for the electron in quantum and classical physics is presented. The most impressive achievement related to the introduction of the chronon hypothesis in the realm of QM comes from the description of a…

An exotic physical phenomenon, involving optical waves, synthetic magnetic fields, and time reversal, has been directly observed for the first time, following decades of attempts. The new finding could lead to realizations of what are known as topological phases, and eventually to advances toward fault-tolerant quantum computers, the researchers say.

The new finding involves the non-Abelian Aharonov-Bohm Effect and is published in the journal Science by MIT graduate student Yi Yang, MIT visiting scholar Chao Peng (a professor at Peking University), MIT graduate student Di Zhu, Professor Hrvoje Buljan at University of Zagreb in Croatia, Francis Wright Davis Professor of Physics John Joannopoulos at MIT, Professor Bo Zhen at the University of Pennsylvania, and MIT professor of physics Marin Soljačić.

The finding relates to gauge fields, which describe transformations that particles undergo. Gauge fields fall into two classes, known as Abelian and non-Abelian. The Aharonov-Bohm Effect, named after the theorists who predicted it in 1959, confirmed that gauge fields — beyond being a pure mathematical aid — have physical consequences.

A talk by Dave Bacon during the Industry session of the 14th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2019), Day 3. TQC 2019 was hosted June 3–5, 2019 by the Joint Center for Quantum Information and Computer Science at the University of Maryland (QuICS). More information about TQC can be found at https://www.tqcconference.org.