Questions tagged [cirq]

A python framework for creating, editing, and invoking Noisy Intermediate Scale Quantum (NISQ) circuits. It is a Python library for writing, manipulating, and optimizing quantum circuits and running them against quantum computers and simulators.

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Variational Quantum Eigensolver (VQE) by scipy minimize in cirq does not work

I tried to make a cirq program calculating an eigenvalue of the observable by VQE. Inspired by the qulacs VQE tutorial, I defined a cost function from the expectation value of the observable with ...
Weongyu Lee's user avatar
3 votes
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Quantum Optimization via Quantum Label Classification in Quantum Circuits

I have been reading Farhi and Neven's paper on quantum neural networks on quantum circuits. I also found an example - albeit not ideal as pointed out by a couple of users - thank you - in here. ...
Enrique Segura's user avatar
3 votes
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Measuring the expected energy of a quantum circuit

I implemented the following circuit: I am interested in measuring the expected energy of the circuit. I am using Cirq. I am wondering what are the next steps. Sorry if the question seems very basic, ...
Enrique Segura's user avatar
2 votes
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How to take gradient of the `tfq.layers.State` output?

I am using the following code for building a quantum circuit as a custom tf.keras.layers.Layer: ...
Shuhul Handoo's user avatar
2 votes
1 answer
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Merge two Y**0.5 gate into a single Y gate

How can I merge two consecutive cirq.Y**0.5 gates into a single cirq.Y gate with a transformer? I can use ...
Inm's user avatar
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2 votes
1 answer
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In Cirq, how do I separate transpilation from execution in simulator.simulate()?

In Qiskit, there are explicit transpile (where a circuit is transpiled to primitive gates) and backend.run (where the circuit is executed in either statevector simulation or real hardware) steps. What ...
pcr's user avatar
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Simulating density matrices in quantum simulators

I would like to load random quantum states sampled from a given density matrix based on its classical probabilities ie based on the definition of the given density matrix: $\rho = \sum_i p_i |\psi _i \...
quics-ilver's user avatar
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How to define a Clifford Gate while given a tableau in Google Cirq?

I would like to uniformly sample from the group of random Clifford gates. I am aware of the paper https://arxiv.org/abs/2003.09412 where they have designed the algorithm to do this task and even ...
CatQubit's user avatar
2 votes
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Does anyone know how to use TF Quantum with real hardware data?

I'm currently trying to embed a tensorflow model for denoising measurements as a tensorflow quantum model, and at some point I'd like for this to be able to run on hardware. After reading through all ...
Cuhrazatee's user avatar
2 votes
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123 views

Why wont my custom controlled gates in Cirq work on a simulator?

To initialize a state in Cirq, I created a custom controlled rotation and a custom rotation gate. The effect of applying the custom controlled gates to the qubits doesn't seem to affect the state. ...
user14860's user avatar
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How to convert a dataset of different values in [0,1000] to quantum data for training a model using Tensorflow QuantumHaving?

...
Alexander Makalovij's user avatar
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Wrong Expectation value when implementing a VQE for the Heisenberg Hamiltonian

I tried to implement an extended Heisenberg-Hamiltonian as an extra exercise further than my homework. My Hamiltonian is the following: $H = \sum_{NN} \sigma_x\sigma_x + \sigma_z\sigma_z$ I try to ...
Schrödinger314's user avatar
2 votes
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A bug during CIRQ installation

I had the following problem with an installation of the Cirq. When I typed python -m pip install cirq, I got the following line: "Cannot uninstall 'sympy'. It is ...
Elijah's user avatar
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2 answers
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VQE Cirq example

Is my understanding correct that in this example the Hamiltonian measurement is not performed through measuring individual Pauli operators because all its terms are mutually commuting? So, for each ...
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Cirq: Any interesting introductory level example using 2D grid of qubits?

I have already asked this question on reddit.com/r/QuantumComputing. Cirq supports to create quantum circuits composed by qubits having 2D grid structure. We have been preparing educational ...
Abuzer Yakaryilmaz's user avatar
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Would this quantum algorithm implementation work?

I am trying to implement the order finding algorithm on Cirq finding the minimal positive $r$ for coprime $x$ and $N$ satisfying the equation $x^r \ = \ 1$(mod$ \ N$). In my case, I have set $x \ = \ ...
Jack Ceroni's user avatar
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Cirq compilation process

Cirq compilation process. I cannot find the documentation that describes the internal structure of the library Cirq by Google. There is much information related to high level functions, but none ...
user29482's user avatar
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How to convert a custom observable matrix to a Cirq observable for simulation?

I aim to conduct a Cirq simulation using a custom observable. However, the measure_observables function in Cirq requires an Iterable of cirq.PauliString, making it challenging to directly use a custom ...
saguira's user avatar
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How can we see on Cirq that Google Sycamore has 54 qubits?

Hello, can you explain how to see in Google Cirq that the figure above is a 54 qubits quantum computer ? thanks
Andlan Zhang's user avatar
1 vote
1 answer
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Need help regarding building a custom VQE

I want to write code for a custom Variational Quantum Eigensolver (VQE) capable of computing eigenvalue(s) for non-Hermitian systems, based on this paper. I have formulated a cost function (provided ...
Bravyi's user avatar
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How to create a 3-D state (array) of qubits in qiskit or cirq etc?

I want a 3-D cube-like array for state of qubits, on which I want further to implement different sets of rotations, etc, for cryptographic means. You can create a 2D grid qubit in cirq with ...
Syed Shahmir Kazmi's user avatar
1 vote
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Tensorflow_quantum hybrid models tf-quantum

I am trying to QCNN for MNIST classification equivalent to that built in. I’m having problems trying to pass my quantum circuit built with cirq as a Keras layer. Here’s what I have: ...
Kieran McDowall's user avatar
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Is there a way to find the computational resources required to perform a simulation of n- qubits in Cirq similar to qsim?

I’m trying to model basic spin chains in 1D using VQE (ideal circuit) with cirq and qsim. The models have between 10-20 sites and varying interactions (nearest neighbour, next to nearest neighbour etc)...
lake_apricot's user avatar
1 vote
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35 views

How to Find a circuit that evolves from one density matrix to another(qiskit or cirq)

given two density matrices, dmBefore and dmAfter, I want to generate(find) a circuit in Qiskit or Cirq that starting initaliazed with dmBefore ends with dmAfter after it's execution. Is it possible?. ...
Luis ALberto's user avatar
1 vote
1 answer
344 views

Marking a specific quantum state in the oracle function in the Grover's algorithm

I have a simple implementation of Grover's algorithm. As depicted in the results below, the oracle function marks the state |111>. How can I change the Oracle function to mark |010>? ...
Hamideh's user avatar
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Two-time correlators in Cirq?

Is there a way to calculate two-time correlators in Cirq directly? For example, suppose we have an initial mixed state described by a density matrix $\rho_0$, and we want to obtain in our quantum ...
Zarathustra's user avatar
1 vote
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77 views

How can i describe Custome Gate Sets in Cirq?

i try to create a Custome GateSet with the CompilationTargetGateset class but it does not work. ...
Qubii's user avatar
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Is there a method in pyQuil to create logical boolean gates

is there another way to represent a boolean gate. The straight forward way would be to define a gate my a matrix and then apply this gate to the circuit. What i mean by that? For Example an AND-Gate ...
Qubii's user avatar
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Convert an integer to its basis state in Cirq

I am trying to implement Quantum Adder using QFT in Cirq. I previously did the same problem using Pennylane, in which I converted an integer into its Basis state using the BasisStatePreparation method ...
Jessica John Britto's user avatar
1 vote
0 answers
134 views

How to rewrite this Cirq problem into Qiskit?

I have a following example problem in Cirq, representing a very simple operator given by $$ \hat{H} = a^\dagger_0a_2 + a_0a^\dagger_1 + 0.9\, a^\dagger_0a_1a^\dagger_2a^\dagger_3 + a^\...
Eenoku's user avatar
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duality quantum computing simulation

I am a starter of this quantum mostly new to quantum computing but I wonder if there is any option of simulating duality quantum computing in qiskit or IBM q or any other alternative way? Duality ...
CADENTIC's user avatar
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155 views

Amplitude Amplification applied to HHL Algorithm

I’m trying to understand and implement the amplitude amplification algorithm described in the HHL paper. I’m using the cirq implementation of the HHL algorithm as my starting point. I have a couple of ...
Markivaira's user avatar
1 vote
0 answers
44 views

Cirq: How to change `atol` in `validate_density_matrix` when using `DensityMatrixSimulator`

I have a code that essentially looks like this ...
Turbotanten's user avatar
1 vote
0 answers
104 views

Quantum Circuits for Time-Series Data

I am currently working with a dataset with autocorrelated features, i.e, x(t) affects the value of x(t+1) which affects the value of x(t+2). Suppose this is the circuit representing x(t): Does ...
Lakshit Dabas's user avatar
1 vote
0 answers
146 views

How to avoid Cirq: State_vector is not normalized error for Feedback-loop in optimizer?

I am doing a VQE in Cirq, but sometimes I get this error while running steps of the classical optimization loop: State_vector is not normalized instead had norm 1.0000000010132789 And therefore the ...
Schrödinger314's user avatar
1 vote
0 answers
338 views

Implementing the HHL algorithm with negative eigenvalues (Cirq)

How do I implement the HHL with negative eigenvalues? This paper (https://arxiv.org/abs/1803.01486) says that: what if $\lambda<0$? This problem actually does not hard to solve, since we can ...
user3886914's user avatar
1 vote
0 answers
120 views

Adding Quantum State Tomography Step to HHL Algorithm (Cirq)

Over the past month, I have been learning about the HHL algorithm and am interested in extending the Cirq implementation to include the quantum state tomography step to extract the amplitudes or ...
quantum_novice's user avatar
1 vote
0 answers
44 views

Can We Currently Import Quantum Datasets (Datasets Containing Quantum Data) Onto NISQ-era Quantum Computers?

I'm still investigating the TFQ whitepaper. In one section of the paper, the authors say this with respect to Quantum Datasets In general, [a quantum dataset] might come from a given black-box ...
Darien Schettler's user avatar
1 vote
0 answers
110 views

Ising Model, Graphs, and Cirq

How would you explain, pictorially and without too much overhead, an interaction between the qubits on this model using Cirq? I am interested in trying to map accurately the ansatz on Cirq to a ...
Enrique Segura's user avatar
1 vote
2 answers
459 views

How to calculate the probabilities of observing quantum states using the "expectation_from_wavefunction" in cirq (and why)

I am currently simulating some quantum circuits, and want to calculate the probabilities of observing each individual state. I am able to use Cirq for this, and calculate it using $P_{00} = |\alpha|^2$...
Thomas Hubregtsen's user avatar
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Initialize circuit by density matrix (i.e. mixed state) by Cirq, Qiskit, QuTip

I want to do a simulation involving: mid-circuit measurement (i.e. based on the measurement result of some qubits to append further gates on other qubits; e.g., Pauli error correction in entanglement ...
Showhands's user avatar
0 votes
0 answers
49 views

How to best implement this algorithm?

I am trying to design an algorithm to find a solution to a certain problem. I have N qubits which encode the problem (let's call them the problem qubits) and one check_qubit (which is flipped to |1>...
Q.Ask's user avatar
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Grover's algorithm for max cut problem - Implementation in cirq

I am using the Grover's algorithm for max cut problem using an oracle for the graph described below to check whether it admits a valid 2-coloring. Here are the edges: (0,3),(0,4),(1,3),(1,4),(2,3),(2,...
Hamideh's user avatar
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Understanding the meaning of [2, 2] for input_register and target_register in a custom Cirq gate

I'm learning a custom gate implementation from google Cirq official tutorial of shor algorithm(https://colab.research.google.com/github/quantumlib/Cirq/blob/master/docs/experiments/shor.ipynb#scrollTo=...
Tonight223's user avatar
0 votes
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177 views

tensorflow, tensorflow-quantum, tensorflow-federated latest version compatibility?

I have been working with on some research on tensorflow, tensorflow-quantum and tensorflow-federated and the problem with that is I just can't install those three at my google colab and I tried ...
Rayhan's user avatar
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1 answer
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How to change the qubits of a cirq Circuit?

I am constructing generic circuits, and I would like to change the qubits after creating the circuits. Is there a way in cirq to do so? for instance: ...
sailx's user avatar
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Topmost Universal Gate Based Quantum Simulator?

I am Elijah I'm interested in Drug Discovery and Materials Simulation. I want to purchase a gate based Quantum Simulator for research. I received a proposal. Full State Simulator 30 Qubits on Laptop, ...
Elijah Connor's user avatar
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47 views

Why importing cirq_ionq gives an unexpected argument error

I'm trying to install cirq_ionq, a python library for running cirq circuits on IonQ's quantum hardware. However, when I try importing it I get an unexpected argument error: ...
MeltedStatementRecognizing's user avatar
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Circuit gives unexpected phase factor (cirq)

I implemented the following circuit on cirq: For clarity: the circuit consists of X gates, (controlled) Hadamard gates (H), N-toffoli gates, and reset operations (R). The (1,4) qubit is the one I ...
Q.Ask's user avatar
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