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Why Large Hadron Collider predictions can miss the mark, and a new way to fix it

Estimating things that exist is generally easy, but when it comes to estimating things that do not exist, it’s more difficult. This is something physicists from Poland and the UK are well aware of. To improve current simulations of high-energy particle collisions, they have developed a more accurate method for estimating the impact of calculations that are not performed.

Prediction can be difficult, especially when it comes to the future, as Niels Bohr—one of the fathers of quantum mechanics—once said. The fundamental problem with predicting the future lies in the simple fact that we just do not know it. A somewhat similar challenge arises in the calculations used to model high-energy particle collisions: For them to be useful, one must be able to estimate the impact of calculations that are not performed.

Physicists Matthew A. Lim from the University of Sussex in Brighton and Dr. Rene Poncelet from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow have presented a new approach to this issue in the journal Physical Review D.

Quantum Memory Isn’t What We Thought: Physicists Reveal a Hidden Duality

An international team of scientists has taken a closer look at how memory functions in quantum systems and their time evolution. Their study reveals that whether a quantum process appears to have memory depends on how it is examined. From one angle, the process may seem completely memoryless. From another, traces of past behavior remain visible. The findings open new paths for research in quantum science and emerging technologies.

In classical physics, memory is defined in a straightforward way. If a system’s future behavior depends only on its current condition, it is considered memoryless. If earlier states continue to influence what happens next, the system is said to have memory.

Quantum physics complicates this picture. Quantum systems can store and transmit information in ways that have no counterpart in classical science. In addition, measurement is not just a passive observation. It plays an active and fundamental role in how quantum systems evolve.

What’s going on inside quantum computers? New method simplifies process tomography

Quantum computers work by applying quantum operations, such as quantum gates, to delicate quantum states. Ideally, quantum computers can solve complex equations at staggeringly fast speeds that vastly outpace regular computers. In real hardware, the operations of quantum computers often deviate from the ideal behavior because of device imperfections and unwanted noise from the environment. To build reliable quantum machines, researchers need a way to accurately determine what a quantum device is actually doing.

Quantum process tomography (QPT) is a standard method for this. However, traditional QPT becomes very costly as the system grows, because the number of required measurements and calculations increases rapidly with the number of qubits.

To address this challenge, a research team from Tohoku University, the Nara Institute of Science and Technology (NAIST), and the University of Information Technology (Vietnam National University, Ho Chi Minh City) has introduced a new framework called compilation-based quantum process tomography (CQPT). The work is published in Advanced Quantum Technologies.

Debugging a quantum processor: New method pinpoints qubit errors during logical operations

Researchers at the University of Innsbruck, together with partners from Sydney and Waterloo, have presented a new diagnostic method for quantum computers. It makes errors in individual quantum bits visible during logical calculation and evaluates them. The new method was demonstrated on an ion trap quantum processor in Innsbruck. It can be used to identify critical error sources—a key to developing more robust, fault-tolerant quantum processors.

In Physical Review X, the researchers present a scalable method that can be used to reliably characterize logical quantum operations at the level of the underlying quantum bits. Cycle error reconstruction identifies which physical errors influence the performance of logically encoded gates.

“With cycle error reconstruction, we can quantitatively capture the error structure and clearly distinguish between correctable and uncorrectable contributions,” says first author Robert Freund from the Department of Experimental Physics.

Mysteries of Math and the Langlands Program — Episode 1

The first in a series of 4 lectures by Edward Frenkel filmed at MSRI, Berkeley and broadcast on the Japanese TV channel NHK in the Fall of 2015 in the “Luminous Classroom” series. The lectures went from elementary topics such as Pythagoras theorem, prime numbers and symmetries to Fermat’s last theorem and the general Langlands conjectures, and to the recent work connecting the Langlands Program to Quantum Physics. Even though the Intro is in Japanese, the lecture itself is in English.

Encryption: A Key Guardian of Our Digital Future

By Chuck Brooks and Bill Bowers.


Every time you send a text, pay for groceries with your phone, or use your health site, you are relying on encryption. It’s an invisible shield that protects your data from prying eyes. Encryption is more than just a technological protection; it is the basis for digital trust.

Encryption is more than just safeguarding data; it is also about protecting people. It helps ensure privacy by protecting persons from spying and exploitation. And it is widely adopted to help ensure digital transaction security. For National Security it serves to protect key infrastructure and government communications. And it has a human rights function by providing citizens with peace of mind by ensuring the safety of their personal information. In places where surveillance is widespread, encryption can even defend free expression and opposition. It is a human right in this digital age.

In my book Inside Cyber: How AI, 5G, IoT, and Quantum Computing Will Transform Privacy and Security, I referred to encryption as the “linchpin of privacy and commerce in a connected society.” Without it, the digital economy would crumble under the strain of criminality, fraud, and spying.

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