The Deutsch-Jozsa algorithm is a quantum algorithm, proposed by David Deutsch and Richard Jozsa in It was one of first examples of a. Ideas for quantum algorithm. ▫ Quantum parallelism. ▫ Deutsch-Jozsa algorithm. ▫ Deutsch’s problem. ▫ Implementation of DJ algrorithm. The Deutsch-Jozsa algorithm can determine whether a function mapping all bitstrings to a single bit is constant or balanced, provided that it is one of the two.

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Specifically we were given a boolean function whose input is 1 bit, f: Retrieved from ” https: Archived from the original on Rapid solutions of problems by quantum computation.

This matrix is exponentially large, and thus even generating the program will take exponential time. All articles lacking reliable references Articles lacking reliable references from May All articles with dead external links Articles with dead external links from September Articles with permanently dead external links. A constant function always maps to either 1 or 0, and a balanced function maps to 1 for half of the inputs and maps to 0 for the other half.

Further improvements to the Deutsch—Jozsa algorithm were made by Cleve et al. First, do Hadamard transformations on n 0s, forming all possible inputs, and a single 1, which will be the answer qubit. In the Deutsch-Jozsa problem, we are given a black box quantum computer known as an oracle that implements some function f: Skip to main content. The Deutsch-Jozsa algorithm can determine whether a function mapping all bitstrings to a single bit is constant or balanced, provided that it is one of the two.

It preceded other quantum algorithms such as Shor’s algorithm and Grover’s algorithm. The algorithm is as follows. Applying the quantum oracle gives.

Deutsch–Jozsa algorithm – Wikipedia

The Deutsch—Jozsa Algorithm generalizes earlier work by David Deutsch, which provided a solution for the simple case.

A Hadamard transform is applied dsutsch each bit to obtain the state.

Constant means all inputs map to the same value, balanced means half of the inputs maps to one value, and half to the other.


Deutsch’s algorithm is a special case of the dwutsch Deutsch—Jozsa algorithm. We apply a Hadamard transform to each qubit to obtain.

Deutsch–Jozsa algorithm

The algorithm was successful with a probability of one half. Proceedings of the Royal Society of London A. It was one of first examples of a quantum algorithm, which is a class of algorithms designed for execution on Quantum computers and have the potential to be more efficient than conventional, classical, algorithms by taking advantage of the quantum superposition and entanglement principles.

At this point the last qubit may be ignored. From Wikipedia, the free encyclopedia. Testing these two possibilities, we see the above deutsh is equal to. We know that the function in the black box is either constant 0 on all inputs or 1 on all inputs or balanced returns 1 for half the domain and 0 for the other half.

By using this site, you agree to the Terms of Use and Privacy Policy. Unlike Deutsch’s Algorithm, this algorithm required two function evaluations instead of only one. This page was last edited on 10 Decemberat More formally, it yields an oracle relative to which EQPthe class of problems that can be solved exactly in polynomial time on a quantum computer, and P are different.

Universal quantum simulator Deutsch—Jozsa algorithm Grover’s algorithm Quantum Fourier transform Shor’s algorithm Simon’s problem Quantum phase estimation algorithm Quantum counting algorithm Quantum annealing Quantum algorithm for algoriyhm systems of equations Amplitude amplification. The algorithm as Deutsch had originally proposed it was not, in fact, deterministic. Since the problem is easy to solve on a algoritthm classical computer, it does not yield an oracle separation with BPPthe class of problems that can be solved with bounded error in reutsch time on a probabilistic classical computer.

The task is to determine whether f is constant or balanced. References David Deutsch, Richard Jozsa. Applying this function to our current state we obtain. For a conventional randomized algorithma constant number of evaluation suffices to produce the correct answer with a high probability but 2n-1 evaluations are still required if we want an answer that is always correct.


If it is 0, the function is constant, otherwise the function is balanced. It is also a deterministic deutsvhmeaning that it always produces an answer, and that answer is always correct. Some but not all of these transformations involve a scratch qubit, so room for one is always provided.

The motivation is to show a black box problem that can be solved efficiently by a quantum computer with no error, whereas a deterministic classical computer would need a large number of queries to the black box to solve the problem.

This is partially based on the public domain information found here: Next, run the function once; this XORs the result with the answer qubit.

In Deutsch-Jozsa problem, we are given a black box computing a valued function f x1, x2, Quantum circuit Quantum logic gate One-way quantum computer cluster state Adiabatic quantum computation Topological quantum computer.

The algorithm builds on an earlier work by David Deutsch which gave a similar algorithm for the special case when the function f x1 has one valued variable instead of n. It was one of the first known quantum algorithms that showed an exponential speedup, albeit against a deterministic non-probabilistic classical compuetwr, and with access to a blackbox function that can evaluate inputs to the chosen function. Unlike any deterministic classical algorithm, the Deutsch-Jozsa Algorithm can solve this problem with a single iteration, regardless of the input size.

For a conventional deterministic algorithm, 2n-1 evaluations of f will be required in the worst case. Views Read Edit View history. Nielsen and Isaac L. In layman’s terms, it takes n-digit binary values as input and produces either a 0 or a 1 as output for each such value.

The Deutsch-Jozsa quantum algorithm produces an answer that is always correct with just 1 evaluation of f. Charge qubit Flux qubit Phase qubit Transmon.