8

They have different error rates because they are two different physical devices! This relates to the manufacturing processes of these chips. Every device is unique and will have its own fingerprint meaning its own error rate. Of course this is not something that manufactures do on purpose, but a side effect of making these qubit devices. It’s very difficult ...


5

What follows turned out to be a rather technical explanation, so I'll start with the main point: The qubit state can change the resonator's state, and the resonator's state can be easily measured only if there is a large different in frequencies between the qubit and the resonator. Let's model a qubit as a two-level system and a resonator as a harmonic ...


4

At Xanadu, we're using integrated quantum photonics to build our photonic quantum computing chips. In this case, we have integrated chips containing waveguides --- these are coupled to lasers to generate input resource states, undergo manipulation on the chip, and then are measured via a variety of detectors available in quantum optics. These can include ...


4

I am going to try to give guesses that can make sense: More qubits does not mean better machines. They may be less noise-tolerant and with less connectivity between qubits. That is why, when you benchmark them (with or without error-correction), you look first at the simplest implementations of state of art algorithms. Plus, you may change some calibrations ...


3

By coincidence, this article just came out on Ars Technica which might answer some of your questions. (This is not an endorsement of everything written in that article. But the author basically asked, and researched, the same question that you're asking.) The TL;DR answer is that superconducting qubits are manufactured and allow for better control over ...


3

Although it doesn't explicitly say it in the paper from Google, the diagrams in the paper are missing a qubit along the top edge. Most likely this is the "bad" qubit that wasn't used.


3

When I visited the Google Hardware Lab, they were extremely secretive about everything. It is unlikely anyone will be able to answer this question except for the narrow range of Google Hardware Lab employees, and the ones I know are not very open about what Google is doing. What I can do is answer what a different superconducting-qubit hardware company (D-...


2

This is an extension of the Anin Post above (I have not been able to access the Anin account again, so have created a new one under the tag 'systematic'. Quantum biology cannot simply solve the practical concerns of quantum computing as they stand - as biology is not simply a form of semiconductor or quantum computer. I note that leading scholars such ...


2

According to comment provided by user gIS, there was no progress in implementing qRAM as proposed in the paper. However, some additional information on qRAM physical implementation can be found on this forum here.


2

I would add that thermic noise, radiocative background (mainly cosmic rays) can play role in different error rate as those noise sources are different for each quantum processor. Moreover, as a user of IBM Q, you probably know that quantum processors are sometimes under maintenance. Since each processor is maintained in different time, their runtime is ...


1

I know this isn't really what you're thinking of with your question, but measurement-based quantum computing is pretty well studied. Under the many-worlds interpretation, the system counts as open for that protocol, because every time you perform a measurement you're becoming entangled with the system.


1

Quantum computers are susceptible to these errors/noise because of physical disturbances. An example of this is if some molecule in the surrounding air were to bump or approach the qubit it would transfer some kinetic energy and maybe affect the state. Another example is if a qubit interferes with any adjacent qubit, if they "bump" into one another their ...


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