# If the universe is a turing machine, must it be one without an oracle?

Contents

## Is the universe a Turing machine?

Digital physics

All known laws of physics have consequences that are computable by a series of approximations on a digital computer. A hypothesis called digital physics states that this is no accident because the universe itself is computable on a universal Turing machine.

## Does a Turing machine only have one accept state?

The number of states required depends on your Turing machine model; a multi-tape machine could probably use fewer states, but a one-tape machine will probably require 201.

## Can a Turing machine not have an accept state?

Turing machines are defined to have only a finite number of states. Since every accepting state is a state, it’s impossible to have infinitely many accepting states.

## Can a Turing machine run infinitely?

In particular, a TM can run forever. Definitions: Let L⊆Σ∗ be a language. If there exists a TM M such that for all x∈L, M halts and accepts x, and for all x∉L, M halts and rejects x, then M decides L (and L is said to be “decidable”).

## Is quantum physics Turing complete?

The quantum computing gate model is not Turing complete. (Rea- son: quantum gates compute only total functions, functions defined everywhere.)

## Is life Turing complete?

This has the same computational power as a universal Turing machine, so the Game of Life is theoretically as powerful as any computer with unlimited memory and no time constraints; it is Turing complete.

## How does a Turing machine reject?

How does a Turing machine reject? M rejects a string w if it enters the reject state when run on w. M loops infinitely (or just loops) on a string w if when run on w it enters neither the accept or reject state. M does not accept w if it either rejects w or loops infinitely on w.

## How many final states can a Turing machine have?

It depends on how you’re defining Turing Machines – these are theoretical things where the definitions can vary based on what conventions you like to adopt – but you can think of a Turing machine as having accepting states like, e.g., DFAs and PDAs, or as having two fixed states named “halt accept” and “halt reject”.

## Can Turing machines have more than 1 final state?

There is no restriction that states how many accepting states a particular Turing machine must have. The machines will differ from problem to problem. Nor is there any statement that states having a single accepting state is the best, and that other accepting states are “unnecessary.”

## Are quantum computers more powerful than Turing machines?

It is known that Turing machines are not so efficient, though they polynomially simulate classical computers. Quantum computers are believed to be exponentially more efficient than Turing machines. In this sense, you can beat Turing machines (if you could only build a scalable quantum computer).

## Can a classical computer simulate a quantum computer?

Classical computers can efficiently simulate the behavior of quantum computers if the quantum computer is imperfect enough.

## Are quantum computers nondeterministic?

Quantum mechanics is usually described as being “not deterministic”, but the word “nondeterministic” is used in a specialized way in theoretical computer science. One meaning, which applies to quantum mechanics, is just ‘not deterministic’.

## Is a quantum computer a Turing machine?

Quantum computer is a non-Turing machine in principle. Any quantum computing can be interpreted as an infinite classical computational process of a Turing machine. Quantum computer introduces the notion of “actually infinite computational process”.

## Do non-deterministic Turing machines exist?

The concept of Non Deterministic Turing Machine is purely theoretical – there is no non-deterministic turing machine available.

## Can a Turing machine simulate a non-deterministic Turing machine?

Any nondeterministic Turing machine N can also be simulated by a deterministic machine M with two inputs: the user input string w ∈ Σ∗ , and a so-called advice string x ∈ Ω∗ , where Ω is another finite alphabet. Only the first input string w is actually given by the user.

## Which one is not a type of Turing machine?

Discussion Forum

Que. Which of the following a turing machine does not consist of?
c. state register
d. none of the mentioned

## Which is more powerful deterministic Turing machine or non-deterministic Turing machine?

Non-determinism is more powerful than determinism for pushdown automata. But it makes no difference for finite automata. Quite surprisingly, the deterministic and non-deterministic Turing machines are the same in power.

## What is universal Turing machine in automata?

In computer science, a universal Turing machine (UTM) is a Turing machine that simulates an arbitrary Turing machine on arbitrary input. The universal machine essentially achieves this by reading both the description of the machine to be simulated as well as the input to that machine from its own tape.

## Can universal Turing machine simulate itself?

So Turing machines can have themselves as input. So they can simulate themselves(this technique have been used in many proofs i saw).

## What is the difference between Turing machine and universal Turing machine?

A Turing machine is (a formal model of) a computer. A universal Turing machine is a specific program. Or, more precisely, a computer on which someone programmed a Turing machine simulator. You can do any algorithmic computation if I let you use my computer.

## Can a universal Turing machine simulate any Turing machine?

The Universal Turing machine can go on then to simulate M on the rest of the content of the input tape. A Universal Turing machine can thus simulate any other machine.