quantum computer is a device that performs quantum computing. Such a computer is different from binary digital electronic computers based on transistors.
Whereas common digital computing requires that the data be encoded into binary digits (bits), each of which is always in one of two definite states (0 or 1), quantum computation uses quantum bits or qubits, which can be in superpositions of states.
A quantum Turing machine is a theoretical model of such a computer and is also known as the universal quantum computer. The field of quantum computing was initiated by the work of Paul Benioff[2] and Yuri Manin in 1980,[3] Richard Feynman in 1982,[4] and David Deutsch in 1985.[5]
As of 2018, the development of actual quantum computers is still in its infancy, but experiments have been carried out in which quantum computational operations were executed on a very small number of quantum bits.[6]
Both practical and theoretical research continues, and many national governments and military agencies are funding quantum computing research in additional effort to develop quantum computers for civilian, business, trade, environmental and national security purposes, such as cryptanalysis.[7]
A small 20-qubit quantum computer exists and is available for experiments via the IBM Quantum Experience project. D-Wave Systems has been developing their own version of a quantum computer that uses annealing.[8]
Large-scale quantum computers would theoretically be able to solve certain problems much more quickly than any classical computers that use even the best currently known algorithms, like integer factorization using Shor’s algorithm (which is a quantum algorithm) and the simulation of quantum many-body systems.
There exist quantum algorithms, such as Simon’s algorithm, that run faster than any possible probabilistic classical algorithm.[9]
A classical computer could in principle (with exponential resources) simulate a quantum algorithm, as quantum computation does not violate the Church–Turing thesis.[10]:202
On the other hand, quantum computers may be able to efficiently solve problems which are not practically feasible on classical computers.
But can it kill Schrodinger’s cat?..................
Love the Landauer quote at the end. I’ve seen so many basic new product programs (forget about the quantum aspects) that have run into significant issues because of this:
“...does not in its current form take into account all possible sources of noise, unreliability and manufacturing error, and probably will not work.”
Your summation sounds MUCH more positive about the future of quantum computing than the author’s.
He seems quite bitter against quantum computing :)
Maybe he lost a girl over it
He urged proponents of quantum computing to include in their publications a disclaimer along these lines: “This scheme, like all other schemes for quantum computation, relies on speculative technology, does not in its current form take into account all possible sources of noise, unreliability and manufacturing error, and probably will not work.”
He should check with the Chinese who claim to have a working quantum computer and the quantum communications tech to go with it.
Is that too much to ask?
If you really want to make progress in Quantum Computing, convince the Sex Industry it is in their best interest to apply it.
In contrast to a classical bit, which can only be in one of its two basic states, a qubit can be in any of a continuum of possible states, as defined by the values of the quantum amplitudes α and β. This property is often described by the rather mystical and intimidating statement that a qubit can exist simultaneously in both of its ↑ and ↓ states.
Yes, quantum mechanics often defies intuition. But this concept shouldn’t be couched in such perplexing language. Instead, think of a vector positioned in the x-y plane and canted at 45 degrees to the x-axis. Somebody might say that this vector simultaneously points in both the x- and y-directions. That statement is true in some sense, but it’s not really a useful description. Describing a qubit as being simultaneously in both ↑ and ↓ states is, in my view, similarly unhelpful. And yet, it’s become almost de rigueur for journalists to describe it as such.
In a system with two qubits, there are 22 or 4 basic states, which can be written (↑↑), (↑↓), (↓↑), and (↓↓). Naturally enough, the two qubits can be described by a quantum-mechanical wave function that involves four complex numbers. In the general case of N qubits, the state of the system is described by 2N complex numbers, which are restricted by the condition that their squared magnitudes must all add up to 1.
While a conventional computer with N bits at any given moment must be in one of its 2N possible states, the state of a quantum computer with N qubits is described by the values of the 2N quantum amplitudes, which are continuous parameters (ones that can take on any value, not just a 0 or a 1). This is the origin of the supposed power of the quantum computer, but it is also the reason for its great fragility and vulnerability.
...
That's the first quantum computing explanation I've read that I understand.
It has gotten to the point where many researchers in various fields of physics feel obliged to justify whatever work they are doing by claiming that it has some relevance to quantum computing.
...
The same goes for climate change and graphene.
Quantum computing...Fusion power stations...
Two peas from the same pod. IMHO
A hard-headed engineer:
Like my father, who designed jets and rockets for a living. Yep, he would have lost interest (if he ever had it) - and he was on the Today Show once for his acclaimed work.
This was a good article on an over-hyped concept.