April 2024 Qruiseletter
Hey!
Here’s the April edition of the Qruise newsletter - the Qruiseletter! Providing you all the latest Qruise news & updates from the last month.
This edition covers:
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OPTIMAL CONTROL OF TRAPPED IONS
At Qruise, our mission is to make quantum optimal control as quick and easy as possible. This is evidenced in our latest work on trapped ions, where we enhanced the fidelity of a simulated 2-qubit entangling gate from 96.48% to 99.99% in the presence of realistic classical control imperfections.
We firstly set up our model of the trapped ions system, including the control electronics limitations, such as bandwidth constraints, that distort the quantum dynamics and result in an increased of unwanted phonon-ion entanglement after each pulse.
As demonstrated in the figure above, we then enhanced the fidelity in only 3 simple steps:
1. Starting with an unoptimized square control pulse, we identified unexpected dynamics: after 4 pulses, the qubits did not return to the ground state.
2. Using Qruise’s advanced optimal control algorithms, which are a key feature of our flagship product QruiseOS, we were able to reshape the control pulse to correct for this issue.
3. With these optimized control pulses, our system exhibited the expected dynamics, i.e. the qubits returned to the ground state after 4 pulses!
The versatility of this technique means it can be applied to any type of quantum system. And this is just one feature of QruiseOS that allows researchers to rapidly enhance their fidelities and accelerate their quantum progress!
You can learn more about QruiseOS here!
HAMILTONIAN HOPPING IN TRANSMON QUBITS
One of Qruise’s current focuses is enhancing our Model Learning algorithms in QruiseML. Lately, we’d been having trouble modeling our transmon qubits: no matter how we tuned the qubit frequency, anharmonicity, T1, and T2* knobs of our model, the predictions of the expected state populations of a given circuit were off. Then we realized the qubits don’t just drift continuously but also hop between discrete modes.
In our circuit, we determine the qubit state by sending a measurement pulse to a resonator coupled to the qubit and integrating the in-phase (I) and quadrature (Q) components of the signal. By repeating the measurement many times, we end up with a collection of (I,Q) points, which can be plotted as clouds (top image), with each cloud cluster corresponding to a different state of the qubit, |0>, |1> and |2>.???
IQ clouds, however, lack temporal information, and when we plotted I or Q using a density gradient as a function of time (middle images), we noticed telegraphic noise signatures characteristic of two-level systems. This suddenly explained why our model wouldn’t fit: we were trying to model a system switching between 2 distinct modes as if it was only in 1! ?
And while we can’t prevent this “Hamiltonian hopping”, splitting the data into 2 different modes (bottom image) will allow us to model each independently and gain a better understanding of the system. ?
Stay tuned to find out how this insight enhanced our Model Learning efforts!?
In the meantime, you can learn more about QruiseML here.
PASQuans2.1 1st ANNUAL PROGRESS MEETING
We had a great time at the 1st Annual Progress Meeting of the PASQuanS2.1 project in Castelldefels, Spain. As part of PASQuanS2.1’s mission to develop scalable Rydberg and ion-trapping systems for quantum simulation, Qruise have been creating extremely detailed Digital Twins to assist our experimental partners in modelling their quantum systems.
It was fantastic to connect in-person with our project partners, and we can’t wait to get started on the next phase, which will focus on uniting the hardware and software stacks to create scalable platforms for quantum simulation.
You can read more about the meeting here!
QUANTUMatter 2024
Join us in San Sebastián, Spain for this year’s International Quantum Matter Conference!
From 7-10th May, Qruise will be at Booth #1 - you can swing by any time during the week or book a live demo by sending an email to [email protected].
We look forward to seeing you there!
Interested in our software but can’t attend QUANTUMatter 2024?
Then get in touch with us at [email protected] or book an online demo now!
Qruise GmbH
Am H?lzersbach 7
D-66113 Saarbrücken
+49(0)2244-8414886