By using the Qiskit qasm-simulator, I want to simulate a quantum circuit of 40 qubits. However, the number of qubits 40 is greater than maximum number (24) for qasm-simulator. Is there any possibility to increase this number?
Actually, the maximum number of qubits in the local
qasm_simulator is 30, and 32 for the
ibmq_qasm_simulator. You can see this 30-limit by running
Aer.get_backend('qasm_simulator').configuration().to_dict() and you can see the configuration for the simulator, including the max number of qubits.
However, I believe it is possible to play with the matrix product state option to get a little bit more, I am not sure, I invite you to check this tuto from Qiskit, they might go through it :)
EDIT : Actually the 24-limit comes from BasicAer, I invite you to use the simulators from Aer, or the ibmq_qasm_simulator that have better limits. You can also play with the backend options, see in this documentation from Qiskit that explains pretty much everything there is to know!
Hope this helps :)
If you use
ibmq_qasm_simulator then the maximum number of qubit supported is 32. And you can't increase this number. Here is Qiskit documentation on this simulator.
Remember that simulating quantum system is very resource extensive, and being able to simulating a system with 32 qubits is pretty impressive.