top of page
Writer's picturemansour ansari

A method to put four qubits in superposition using IBM Qiskit



About 2 months ago, I registered on IBM Qiskit for a free IBM account . It is exciting to explore the portal, write code, and run it on a simulator or submit it to a real quantum computer running on the backend. In today's post, I will show you how to put four qubits into superposition using Python. I am currently a beginner in Qiskit.


What is Qiskit?

Qiskit is an open-source quantum computing framework developed by IBM. It allows users to create, manipulate, and execute quantum programs on a variety of different hardware platforms, including IBM's own quantum computers. The platform offers a wide range of tools and features, making it a powerful tool for both researchers and developers looking to explore the possibilities of quantum computing.

One of the main advantages of Qiskit is its ease of use. The platform is built using Python, a popular and widely-used programming language, making it accessible to a wide range of users. This is further enhanced by the wide range of tutorials, documentation, and educational resources provided by IBM, making it easy for new users to get started with quantum computing.

Qiskit also offers a wide range of tools for creating and manipulating quantum programs. The platform includes a quantum circuit composer, which allows users to create and edit quantum circuits in a visual, drag-and-drop interface. Additionally, it has a variety of different quantum algorithms, such as the famous Shor's algorithm, that can be run on the platform. This makes it easy for users to create and test their own quantum programs, even if they lack a deep understanding of the underlying physics.

Another major advantage of Qiskit is its ability to run on a variety of different hardware platforms. The platform is compatible with both simulated and real quantum devices, such as IBM's own quantum computers. This allows users to test and experiment with their quantum programs on a variety of different hardware, giving them a better understanding of how their programs will behave on real devices.

In conclusion, Qiskit is a powerful and easy-to-use quantum computing framework developed by IBM. It offers a wide range of tools and features for creating and manipulating quantum programs, making it accessible to a wide range of users. Additionally, it can run on a variety of different hardware platforms, allowing users to test and experiment with their quantum programs on real devices. These capabilities make Qiskit a valuable tool for researchers, developers, and anyone interested in exploring the possibilities of quantum computing.

We want to put four qubits on superposition, but how do we do that? When using IBM's Qiskit, the answer is straightforward.




S

from qiskit import QuantumCircuit, execute

# Create a quantum circuit with 4 qubits

qc = QuantumCircuit(4)

# Apply the Hadamard gate to each qubit

qc.h(0)

qc.h(1)

qc.h(2)

qc.h(3)

# Execute the circuit on a quantum simulator

backend = Aer.get_backend('statevector_simulator')

job = execute(qc, backend)

result = job.result()

# Print the statevector of the qubits

print(result.get_statevector())

This code applies the Hadamard gate to each of the 4 qubits, putting them in a superposition state of |0⟩ and |1⟩. The statevector_simulator backend is used to simulate the state of the qubits, and the resulting statevector is printed. Please note that, this is an example and it is just a simulation of the qubits state. In order to manipulate the real qubits in a superposition state you need to have a quantum computer and access to it.



So, what is Hadamard gate?


The Hadamard gate is a fundamental building block in quantum computing, used to create superposition and entanglement states of qubits. The gate is represented by the matrix H = (1/√2) * [[1,1],[1,-1]], and when applied to a qubit in the state |0⟩ it will put it in a superposition state of |0⟩ and |1⟩.


The Hadamard gate is a unitary operation, which means that it preserves the norm of the state vector and hence the probability of measuring the qubit in state |0⟩ or |1⟩ is not affected by the operation. The Hadamard gate is also its own inverse, meaning that applying it twice to a qubit will return it to its original state. This property is known as self-inversiveness, and it is a key property that allows for the creation of many quantum algorithms.


One of the most common uses of the Hadamard gate is in the creation of superposition states. Superposition is a key concept in quantum mechanics, where a qubit can exist in multiple states simultaneously. The Hadamard gate is used to create superposition states, which are used as the basis of many quantum algorithms.

The Hadamard gate can also be used in conjunction with other gates to create entanglement states. Entanglement is a property of quantum systems where the state of one qubit is dependent on the state of another. The Hadamard gate can be used to create entanglement between two qubits by applying it to one qubit, and then applying a controlled-not (CNOT) gate to the second qubit. This creates an entanglement state where the state of one qubit is dependent on the state of the other.


In addition, Hadamard gate is also used in many quantum algorithms such as Grover's algorithm, Quantum Phase estimation, and Shor's algorithm. Grover's algorithm is a quantum search algorithm that can search an unsorted database with O(√N) complexity, which is faster than classical algorithms. Quantum Phase estimation is an algorithm that can estimate the eigenvalues of a unitary operator, which is useful in many quantum computing applications.

In conclusion, the Hadamard gate is a fundamental building block in quantum computing, used to create superposition and entanglement states of qubits. It is unitary and self-inversiveness which makes it a versatile tool in many quantum algorithms and operations. The gate is a key component in the development of quantum computing, and its importance will continue to grow as research in this field progresses.


7 views

留言


bottom of page