China

We study the interplay between entanglement and chaos in the time evolution of Bohmian trajectories of a two qubit system, made of coherent states of the quantum harmonic oscillator. This simple quantum system has very rich dynamics from a Bohmian standpoint, since with a proper choice of the physical
parameters one finds ordered (periodic or non-periodic) and chaotic trajectories. We provide strong numerical evidence that the chaotic trajectories of this system are ergodic regardless of the amount of the entanglement and study their impact on the dynamical approximation to Born’s rule when the initial configuration of the quantum particles does not satisfy it.

Quantum 2020

Chaos and entanglement in Bohmian Qubits

qubits

bohmian mechanics

chaos

entanglement

**BQIT is a three day annual workshop** aimed at enabling leading UK and international academics and industrial partners to come together; to explore and discuss future ambitions and challenges in the field of **Quantum Information Technologies.** Since our conception in 2014 we have had 230 speakers and panellists who have presented their work and opinions on a range of topics, from quantum theory to innovation in industry.


### Welcome Message
The BQIT:21 team welcomes you to the eighth Bristol Quantum Information Technologies workshop! 

Last year was the first time in our workshop's history that we had gone fully virtual. The global circumstances that continue to impact us all professionally and personally have forced BQIT once again to be delivered as an all-virtual workshop for 2021. The access this creates to colleagues across the world who would otherwise be unable to join us, as well as being able to make the workshop free for all attendees due to the lower costs involved in delivering an online workshop, are just a couple of the extraordinary benefits of meeting online. This also means that we can welcome three times as many attendees to BQIT than previous years.   

We take this opportunity to thank each of our speakers and poster presenters for contributing their technical content, this year's sponsors, whose support this year enabled BQIT:21 to be free to all attendees, and to all of our attendees for joining us online this year. We recognise the extra energy required to stay connected and motivated during these difficult times, and are hugely encouraged to see so many of you willing to continue to connect with us on an online platform. 

It is our hope that you have a productive and enjoyable time while you engage and interact with BQIT:21, and to everyone that has helped take BQIT:21 online, thank you! 

**The BQIT board and organisation team **


![](https://assets.underline.io/uploads/markdown_image/1/image/a12e0c1ad3410144cb48557690e4ecaf.png)
### This year's workshop agenda is available here: [Virtual BQIT:21](https://drive.google.com/file/d/1QwsSM0ztnxC_lgUKf3TbO3GvnI44AQkY/view?usp=sharing)
For further information, please contact us at: **bqit-admin@bristol.ac.uk**

![](https://assets.underline.io/uploads/markdown_image/1/image/a12e0c1ad3410144cb48557690e4ecaf.png)

Bristol Quantum Information Technologies Workshop

poster

The Institute of Physics and IOP Publishing, in partnership with the Chinese Physical Society (CPS) and the University of Science and Technology of China (USTC) are proud to have brought together the international quantum science community online for this inaugural conference.


Early career and leading researchers from universities, industry and government worldwide came together to share, learn and collaborate on the latest research and emerging areas of high interest across quantum science and technology. The broad themes covered by Quantum 2020 included:

Quantum communication;
Quantum computing and quantum simulation;
Quantum sensing, metrology and imaging;
Quantum information theory, software and algorithms;
Quantum foundations;
Quantum technology in industry.
The four-day event featured talks from world-renowned scientists, interactive poster sessions and two exciting panel discussions on the themes of Quantum Technology in Industry and Quantum Technology Programmes Around the World.


You will need to [register](https://www.iopconferences.org/iop/frontend/reg/tRegisterEmailNew.csp?pageID=978403&eventID=1552&tempPersonID=536224) to obtain a ticket. . If you have already registered you should have been sent an email from Underline (to the email address that you registered with) with the subject line ‘Welcome to Quantum 2020’. This email includes your ticket for the event. 

If you have a ticket and are experiencing problems in accessing the event, please contact us. 

The Institute of Physics and IOP Publishing, in partnership with the Chinese Physical Society (CPS) and the University of Science and Technology of China (USTC) are proud to have brought together the international quantum science community online for this inaugural conference.

Early career and leading researchers from universities, industry and government worldwide came together to share, learn and collaborate on the latest research and emerging areas of high interest across quantum science and technology. 

"One of the promising technical solutions to improve qubit lifetimes is a logical qubit comprised of a Josephson junction located inside of a high Q-factor 3D superconducting cavity. Niobium superconducting cavities used in particle accelerators are able to reach quality factors of ~1e10, potentially enabling storage times approaching seconds. RadiaBeam is presently developing a 3D quarter-wave resonator (QWR) with shape optimized for operation in the quantum regime. This program includes several important steps: development of a QWR cavity with the optimal shape to increase the Q-factor by adopting surface treatment techniques from accelerating cavities; demonstration of the performance of a multi-qubit system with Josephson junctions, and improvement of fabrication techniques to reduce the complexity and costs of the system. The activities for most of the objectives are already ongoing. For example, we recently developed a resonator with the improved shape, machined it out of niobium, and tested it at a temperature of 10 mK. Other ongoing work includes the study of niobium surface treatments, and the use of advanced fabrication techniques such as additive manufacturing (AM), stamping, and hydro- or electro-hydraulic forming. In this paper, we will discuss the current and future fabrication activities of qubit cavities at RadiaBeam.
"
![](https://assets.underline.io/uploads/markdown_image/1/image/7f2315a9324b7f771d2b010b7639c22a.png)

Fabrication approaches to 3D superconducting qubit resonators with a high Q-factor

Alkali and Alkaline Earth Metal Salts of cyclic N4x– Anions, where x = 1, 2 and 3: a First-Principles Crystal Structure Prediction Sergey V. Bondarchuk A recent study of binary MgxNy systems proved that nature is much more inventive than any human imagination [1]. It was found that N4 species can be recovered to ambient conditions in the form of syn-N44– anions in Mg2N4. We have studied recoverability of other similar anions, including syn- and anti-N42–, and found that these are unstable at ambient conditions. Meanwhile, the cyclic form of N4 (tetrazete, c-N4), appeared to be dynamically, mechanically and thermally stable in crystalline form at ambient conditions, that follows from our first-principles crystal structure prediction and ab initio molecular dynamics simulations. Moreover, metal salts of c-N4x– with several alkali and alkaline earth metals are found to be stable in a wide range of oxidation states (x = 1, 2 and 3). Thus, crystal structures of the following salts were predicted and their properties were studied. Depending on both nature of the metal cation and stoichiometry, these demonstrate a wide scattering in properties, namely, band gap, bulk modulus, enthalpy of formation, etc. Thus, further study of such salts is of great importance. References: [1] Laniel D, Winkler B, Koemets E, Fedotenko T, Bykov M, Bykova E, Dubrovinsky L and Dubrovinskaia N 2019 Nat. Commun. 10 451.

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