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Questions tagged [q#]

Q# is a domain-specific programming language used to express quantum algorithms. This tag should be used for questions related to creating/programming quantum algorithms using the 'Q#' language. If the question is unrelated to, or arising from some non-quantum aspect of Q#, it might be better to ask on StackOverflow. If appropriate, also use the [programming] tag.

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How many logical qubits are needed to run Shor's algorithm efficiently on large integers ($n > 2^{1024}$)?

First, I know there are differences in logical qubits and physical qubits. It takes more physical qubits for each logical qubit due to quantum error. Wikipedia states that it takes quantum gates of ...
LeWoody's user avatar
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12 votes
3 answers
4k views

Big Endian vs. Little Endian in Qiskit

I've noticed that Q# favors Little Endian. Meaning that most operations are designed for this type of encoding. Is is it the same with Qiskit?
Sorin Bolos's user avatar
9 votes
1 answer
1k views

Ground state energy estimation - VQE vs. Ising vs. Trotter–Suzuki

Disclaimer: I am a software engineer who is curious about quantum computing. Although I understand some basic concepts, theory and math behind it, I am by no means experienced in this domain. I am ...
Anurag Bhandari's user avatar
8 votes
2 answers
272 views

How does one obtain amplitude information in Q#?

Is it possible to obtain amplitude information (in lexicographic ordering) for a particular qubit register in Q#? For example, in the following code: ...
jman's user avatar
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8 votes
2 answers
285 views

Can we perform quantum mechanical simulations using a quantum computer?

I'm a computer science major who's really keen on physics and quantum mechanics. I have started learning about Q# and D-Wave, but I just wanted to know if it's possible to test quantum mechanical ...
Yashank's user avatar
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7 votes
2 answers
2k views

How to construct the "Inversion About the Mean" operator?

It seems like it should be simple, based on how Nielsen and Chuang talk about it, but I cannot seem to correctly implement the Inversion About the Mean operator ($2|\psi\rangle \langle\psi| - \mathcal{...
nikojpapa's user avatar
  • 501
7 votes
3 answers
1k views

How do you send an array of qubits to an operation in Q#?

I have the following operation in my .qs files: operation myOp(qubits: Qubit[]) : () { // uses elements from the qubit array } How do I send an ...
Mahathi Vempati's user avatar
7 votes
2 answers
1k views

From Q# measurements to Bloch sphere

I would like to represent the state of a qubit on a Bloch sphere from the measurements made with Q#. According the documentation, it is possible to measure a qubit in the different Pauli bases (...
JRial95's user avatar
  • 93
7 votes
1 answer
219 views

Q# Simulation Behavior

I am attempting to run a series of tests on a Q# program I'm running on the local simulator, but I'm not seeing any way to use >1 shot and collect the results of those shots at once, as in ...
Xavier McCaig's user avatar
6 votes
3 answers
107 views

Simulator-dependent implementations in Q#

I have a Q# operation: ...
Craig Gidney's user avatar
  • 37.1k
6 votes
2 answers
488 views

Quantum counting in Q#

I cannot seem to get an estimate for the number of solutions using the quantum counting algorithm described in Nielsen and Chuang, i.e. phase estimation with the Grover iteration acting as $U$. I try ...
nikojpapa's user avatar
  • 501
5 votes
2 answers
154 views

How do I produce circuit diagrams from a Q# program?

If I implement an adder operation in Q#, I'd like to see a quantum circuit diagram of what that adder is doing in order to check that it looks right. Is there a built-in way to do this?
Craig Gidney's user avatar
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5 votes
2 answers
1k views

Measuring entanglement entropy using a stabilizer circuit simulator

I'm trying to simulate stabilizer circuits using the Clifford tableau formalism that lets you scale up to hundreds of qubits. What I want to do is find the entanglement entropy on by splitting my ...
Germ's user avatar
  • 315
5 votes
3 answers
5k views

Overview of Cirq, qiskit, q#, ibmq(circuit board), other [closed]

What is the difference between these frameworks or languages? What are the pros and cons of each of these? Do you know any similar framework/platform/language that gives some more advantages?
Rishwi binnu's user avatar
5 votes
1 answer
361 views

How to see the QASM code corresponding to compiled Q# function?

I'm learning Q#. Is there any way to see the QASM code of a Q# function I write, the same way I can see the disassembly of a C# function?
GideonMax's user avatar
  • 153
5 votes
1 answer
208 views

Q# factorization Method Program

Is there a method to calculate prime factorization in Q# of Visual Studio of Microsoft Quantum Development Kit? In the Python language, it is the sympy.factorint ...
GotohRyo's user avatar
5 votes
2 answers
533 views

Checking value of variable using quantum approach

A beginner question after watching few videos. Say, var=a; var can be either of two values, ...
Dr.PB's user avatar
  • 183
5 votes
1 answer
146 views

Q# installation on Heroku

I'm trying to deploy a simple Quantum App written using Python on Heroku Server which is also using Microsoft's Q#, but getting the below error: ...
Shadab Hussain's user avatar
5 votes
2 answers
922 views

Finding the maximum number of Q# simulatable qubits

I'm new to Q# and I was curious on how one would find the number of Q# simulatable qubits for a specific machine. I know Microsoft has an approximation of 16GB ~ 30 qubits but I wanted a better ...
jman's user avatar
  • 443
4 votes
3 answers
201 views

Does Q# have a bigint type?

Shor's algorithm works with very large integers; larger than 64 bits. So the built-in 64-bit Int type is insufficient for doing the classical processing (e.g. ...
Craig Gidney's user avatar
  • 37.1k
4 votes
1 answer
210 views

What is the corresponding code for finding the state of a qubit on the Bloch sphere?

To find the state of a qubit on the Bloch sphere we use the following formula: \begin{equation} |\psi\rangle=\mathrm{cos}\frac{\theta}{2}|0\rangle+\mathrm{e}^{i\phi}\mathrm{sin}\frac{\theta}{2}|1\...
Coder's user avatar
  • 293
4 votes
1 answer
218 views

How do I write functions that modify operations in Q#?

In Q#'s type documentation, it is mentioned that you can create signatures like this: ...
Craig Gidney's user avatar
  • 37.1k
4 votes
1 answer
1k views

Practical example of Grover's algorithm (in Q#)

Is there any real example for Grover's algorithm but with real database (generated from SQL or file)? I download the Q# development kit & its example, there was one call DatabaseSearchExample ...
Huang Lee's user avatar
4 votes
2 answers
616 views

Q# Error: No namespace with the name "Microsoft.Quantum.MachineLearning" exists

I'm having trouble getting the namespace Microsoft.Quantum.MachineLearning. Here is an example Q# code: ...
MetaInformation's user avatar
4 votes
1 answer
155 views

How do I name the adjoint of an operation in Q#?

For example, if I've defined the operation PlusEqual, I'd like to say operation MinusEqual = Adjoint PlusEqual; but this ...
Craig Gidney's user avatar
  • 37.1k
4 votes
1 answer
822 views

Creating controlled R1 gates in Q#?

I know how to create controlled versions of gates like X, Y, Z. For example, a controlled X gate would be implemented by writing (Controlled X)([control],target); ...
Alex S's user avatar
  • 175
4 votes
1 answer
58 views

Missing types, namespaces, directives, and assembly references

I use VS Code for C# and Unity3D and TypeScript and <...
Muhy's user avatar
  • 163
4 votes
1 answer
469 views

Is there a function in Qiskit to measure tensor products of Pauli operators?

Is there a function in Qiskit similar to this function in Q# which measures strings of Pauli operators applied to different qubits?
sycramore's user avatar
  • 325
4 votes
1 answer
405 views

Installing Q# in jupyter

I have followed all steps described in https://docs.microsoft.com/en-us/quantum/install-guide/qjupyter But I am unable to get through part 3. It is showing syntax error in Python terminal in Jupyter ...
quanity's user avatar
  • 149
4 votes
1 answer
247 views

qsharp.reload() throws error in python

I'm trying to add the Q# machine learning library to my program by ...
Shreyas Pradhan's user avatar
3 votes
2 answers
638 views

How to compute the inverse of an operation in Q#?

I want to implement amplitude amplification using Q#. I have the operation $A$ that prepares my initial state and I need to compute $ A^{-1} $ to implement the algorithm. Is there an easy way to do ...
Sorin Bolos's user avatar
3 votes
1 answer
153 views

How do I get a list of control qubits from Q# operations when tracing the simulation in C#?

I want to write code that prints out the controls of each operation executed during a simulation in Q#. For example this code prints the control counts: ...
Craig Gidney's user avatar
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3 votes
1 answer
100 views

What all parameters can we take into account when comparing different quantum programming languages

I am planning to write a paper which compares Qiskit and Q# in the following circuits/algorithms Bell circuits Controlled swap to test similarity of two registers Phase kickback between two qubits ...
Aryan Arora's user avatar
3 votes
2 answers
373 views

$S^{\dagger}$ gate in Q#

I would like to implement $S^{\dagger}$ gate in Q# and I would like the best way to do it, is it correct to say that $S^{\dagger}$ is equivalent to R1( -Pi()/2 , q) ...
user12910's user avatar
  • 451
3 votes
2 answers
81 views

Testing superposition states in Q#

I am learning Q# so, as I often do, I am writing some unit tests to play with quantum gates. I was able to write these tests for X gate: ...
Daniele Armanasco's user avatar
3 votes
3 answers
460 views

Unit testing for quantum programs?

Does unit testing on real quantum computers make sense as any observation in the quantum system can cause the system to loose its superposition state?
Coder's user avatar
  • 293
3 votes
1 answer
100 views

How can I transform a Result into a Bool in Q# + C# environment?

I'm writing a Q# program and I'm calling an operation defined in the program that outputs a Result (One or ...
Eduardo González's user avatar
3 votes
1 answer
590 views

Counting in Q#: number of solutions

I have this program derived from Microsoft Quantum Katas for counting (see here): ...
Fabrizio Riguzzi's user avatar
3 votes
1 answer
85 views

How do I do printf debugging in Q# in a convenient way?

When initially writing an operator in Q#, I often want to see intermediate values of registers during the computation. This allows me to check that I haven't made ...
Craig Gidney's user avatar
  • 37.1k
3 votes
1 answer
2k views

How to measure in an arbitrary basis in Q#?

Q# has a measurement operator defined as follows according to the docs: operation Measure (bases : Pauli[], qubits : Qubit[]) : Result Where you give a Pauli gate ...
ahelwer's user avatar
  • 4,128
3 votes
1 answer
146 views

Quantum Katas - Tutorials - Oracles - Task 3.3 (OR oracle of all bits except for a single bit)

Let $x$ be an arbitrary state composed of $N$ qubits and $k$ be an integer such that $0\leq k \leq N.$ The task is to ignore the $k$-th bit and to flip the sign of $x$ if any of the remaining bits are ...
Calvin Stefano Mera's user avatar
3 votes
1 answer
525 views

Implement U2 and U3 gate in Q#

I know that U1 equivalent gate of Qiskit in Q# is R1, but I would like to implement U2 and U3 gate of Qiskit in Q#, what is the best way ? Thank you.
user12910's user avatar
  • 451
3 votes
1 answer
437 views

Finding phase angle in Q#

I've trying to measure the phase angle from X axis of a qubit, but unable to find any function in Q# documentation, can anyone help me with this?
Sahil Silare's user avatar
3 votes
1 answer
151 views

Generic matrix exponential in Q#

I am trying to find a way to implement a unitary transformation in Q# that implements e^(iA) where A is a square matrix. However, I only found ways to do this in Q# if A can be represented as a ...
Martin's user avatar
  • 137
3 votes
1 answer
173 views

How to invoke a C# method inside a Q# operation?

Suppose there is a Q# operation as follows: operation Op () : Bool { let result = CSharpMethod (); return result } where ...
Coder's user avatar
  • 293
3 votes
2 answers
64 views

Creating a resource count unit test in Q#

I want to create a unit test in Q# that runs an operation and asserts that it used at most 10 Toffoli operations. How do I do this? For example, what changes do I have to make to the code below? ...
Craig Gidney's user avatar
  • 37.1k
3 votes
1 answer
129 views

Inner product of states in Q#

I have a state $|x\rangle$ and I want to get the expected result when measuring observable $A$ (i.e. get the result of $\langle x| A | x \rangle$). In my case $A$ can be any of the Pauli gates. Does ...
Martin's user avatar
  • 137
3 votes
1 answer
90 views

Type error creating R gate in Q#?

The R operation in Q# is listed by Microsoft in the documentation as follows operation R (pauli : Pauli, theta : Double, qubit : Qubit) : Unit However, when I try ...
Alex S's user avatar
  • 175
3 votes
1 answer
1k views

What is the right way to prepare a specific qubit state in Qiskit / Q#?

There are two possibilities to prepare a qubit in a particular state like $ | - \rangle $ in Qiskit. The first approach is using the initialize function: ...
JulesMhz's user avatar
3 votes
1 answer
172 views

Creating Hamiltonian Simulation Operator in Q#

I am trying to create a unitary operator $U = \sum^{T - 1}_{k=0}$ $|k\rangle$ $\langle k |$ $ \otimes$ $e^{i A k}$ in Q#, where A is a Hermitian matrix. For the beginning, I just want A to be a ...
Martin's user avatar
  • 137