[a] https://www.youtube.com/watch?v=ZCzSnFOV6Pw -> Could be useful

[b] https://www.dwavesys.com/ -> Could be useful

We are still trying to hack the secrets behind Quantum Computing -> as of now I am doing only theoretical investigations with available tools.Takes time.It is too early to predict anything.Let us see.Thanks for asking this question.Appreciate it. Rgds - Nirmal.

it is not in my field, but good to know

Prof. Jose Risomar Sousa: Could you please clarify the phrase "(which are possible)" in your sentence:

"If Quantum computers can solve problems impossible for classical computers (which are possible), then it must mean quantum computers are impossible to develop."?

Yes, such a question has a right to exist. For different reasons. First, too much time and effort has already been spent on creating a quantum computer, and so far there has been no significant success. Personally, I have physical ideas that are not implemented quickly enough, that is, during the active creative life of one generation of scientists, cause great skepticism. Comparison in this context with thermonuclear fusion is quite appropriate. Second, in my opinion, the theoretical basis for the creation of quantum computers should not be quantum mechanics, but quantum-classical mechanics. Therefore, these computers, if they are ever created, will be called quantum-classical computers.

I did so in the enunciate, Nidhal Kamel Taha El-Omari

Dear Jose:

Based on IBM we can say the following: Quantum computing harnesses the phenomena of quantum mechanics to deliver a huge leap forward in computation to solve certain problems.

IBM designed quantum computers to solve complex problems that today's most powerful supercomputers cannot solve, and never will.

Progress has been swift. In a few short years we now have over 20 of the world's most powerful quantum computers, accessible for free on the IBM Cloud

As a developer, you can join the world's largest quantum developer community.

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here's a simple explanation of quantum computing.

For some problems, supercomputers aren’t that super

Until now, we’ve relied on supercomputers to solve most problems. These are very large classical computers, often with thousands of classical CPU and GPU cores. However, supercomputers aren’t very good at solving certain types of problems, which seem easy at first glance. This is why we need quantum computers.

Imagine you want to seat 10 fussy people at a dinner party, where there is only one optimal seating plan out of all the different possible combinations. How many different combinations would you have to explore to find the optimal?

Can you guess how many combinations?

The answer is over 3 million and that's just 10 people around a table.

Larger versions of these kinds of problems stump our most powerful supercomputers, because:

Supercomputers don't have the working memory to hold the myriad combinations of real world problems.

Supercomputers have to analyze each combination one after another, which can take a long time.

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Since 2017 IBM Quantum has been working with clients and partners to solve problems like these. Here are real life quantum computing applications.

Here are some examples:

1- A new generation of electric vehicles through quantum battery technology.

2-Reducing atmospheric carbon emissions using quantum computing aided material discovery.

3-Searching for Higgs events and the origins of the universe.

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Why quantum computers are faster

For over two decades, IBM has been pioneering the development of quantum computer systems to solve these sorts of problems in fundamentally news ways, making use of these two approaches.

Quantum computers can create vast multidimensional spaces in which to represent these very large problems. Classical supercomputers cannot do this.

Algorithms that employ quantum wave interference are then used to find solutions in this space, and translate them back into forms we can use and understand.

Here’s why it matters

One promising quantum algorithm that uses these techniques is called Grover's Search. Suppose you need to find one item from a list of N items. On a classical computer you'd have to check N/2 items on average, and in the worst case you would need to check all N.

Using Grover's search on a quantum computer you would find the item after checking roughly √N of them. This represents a remarkable increase in processing efficiency and time saved. For example, if you wanted to find one item in a list of 1 trillion, and each item took 1 microsecond to check:

Classical computer About 1 week.

Quantum computer About 1 second.

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-- Superfluids:

First we use superfluids to chill superconductors. We get these superconductors very cold – about a hundredth of a degree Celsius above absolute zero: the theoretically lowest temperature allowed by the laws of physics.

-- Superconductors:

When we put electrons through superconductors they pair up into something called Cooper pairs that quantum tunnel through something called a Josephson junction.

Control:

Essentially, this is a superconducting qubit. By firing photons at the qubit, we can control its behavior and get it to hold, change, and read out information.

Superposition:

A qubit itself isn’t very useful. However, by creating many and connecting them in a state called superposition we can create vast computational spaces. We then represent complex problems in this space using programmable gates.

-- Entanglement:

Quantum entanglement allows qubits, which behave randomly, to be perfectly correlated with each other. Using quantum algorithms that exploit quantum entanglement, specific complex problems can be solved more efficiently than on classical computers.

-- Learn quantum computing programming:

You can explore the world of quantum computing for free on the IBM Cloud, and learn to write quantum code – starting with absolute zero experience.

IBM's quantum computers are programmed using Qiskit, a software development kit in Python. Qiskit is free, open source, and accompanied with a comprehensive textbook and semester-long course.

I agree with @Vladimir Valentinovich Egorov

maybe!

As my primary research area is ion traps, I invite you to watch a seminar held in the autumn of 2021 (within the Seminar Series "Virtual Seminar on Precision Physics and Fundamental Symmetries", hosted by CERN) by C. Monroe from Duke University. At the current moment IonQ delivers commercial versions of a QC where you select the desired number of qubits and the experiment is fully controlled by means of a user interface based on Python. Taking into account the vivid interest and the funds globally invested in quantum computing, I am confident that in the near future quantum computers will represent a commercially available technology. Moreover, besides IonQ in the USA, the University of Innsbruck produces quantum computers for the car industry and for financial applications.

This is the link, enjoy!

https://www.youtube.com/watch?v=LEqPlDrMXjs

And a most recent paper on quantum computing with atomic mixtures

Article Universal quantum computation and quantum error correction w...

From general considerations, it follows that these computers, let's call them cautiously computers based on new physical principles, should be a much more productive analogue of the human brain. Therefore, work on the creation of new computers and scientific research on the principles of the functioning of the human brain should be carried out in parallel. This is of course very difficult to do. But difficult does not mean impossible. At the very least, this is a worthy goal for human civilization. Among other things, the setting by mankind of goals that are difficult to achieve will distract it, for example, from destructive wars and contribute to its self-preservation, even if this goal looks like a chimera at first.