[BUG] Performance discrepency in `qml/demonstrations/qrack.py` demo

[andrijapau]

Issue description

The demo claims that QJIT improves Qrack’s execution speed, but when I tested it locally (about four times so far), I observed the opposite—QJIT didn't improve the execution times and also is slower than when the demo was previously run.

• Expected behavior:

The demo claims the following,

• Actual behavior:

Locally, I am seeing,

Aside from the apparent slow down of QJIT Qrack, the trend of QJIT providing a performance boost doesn't seem to hold anymore.

• System information:

Name: PennyLane
Version: 0.40.0.dev49
Summary: PennyLane is a cross-platform Python library for quantum computing, quantum machine learning, and quantum chemistry. Train a quantum computer the same way as a neural network.
Home-page: https://github.com/PennyLaneAI/pennylane
Author: 
Author-email: 
License: Apache License 2.0
Location: /Users/andrija.paurevic/Documents/qml/.venv/lib/python3.10/site-packages
Editable project location: /Users/andrija.paurevic/Documents/pennylane
Requires: appdirs, autograd, autoray, cachetools, diastatic-malt, networkx, numpy, packaging, pennylane-lightning, requests, rustworkx, scipy, tomlkit, typing_extensions
Required-by: PennyLane-Catalyst, PennyLane-Cirq, PennyLane-qiskit, pennylane-qrack, pennylane-qulacs, PennyLane_Lightning, PennyLane_Lightning_Kokkos

Platform info:           macOS-14.7.2-arm64-arm-64bit
Python version:          3.10.16
Numpy version:           1.24.0
Scipy version:           1.15.0
Installed devices:
- lightning.qubit (PennyLane_Lightning-0.40.0.dev43)
- nvidia.custatevec (PennyLane-Catalyst-0.10.0.dev39)
- nvidia.cutensornet (PennyLane-Catalyst-0.10.0.dev39)
- oqc.cloud (PennyLane-Catalyst-0.10.0.dev39)
- softwareq.qpp (PennyLane-Catalyst-0.10.0.dev39)
- qiskit.aer (PennyLane-qiskit-0.40.0.dev0)
- qiskit.basicaer (PennyLane-qiskit-0.40.0.dev0)
- qiskit.basicsim (PennyLane-qiskit-0.40.0.dev0)
- qiskit.remote (PennyLane-qiskit-0.40.0.dev0)
- default.clifford (PennyLane-0.40.0.dev49)
- default.gaussian (PennyLane-0.40.0.dev49)
- default.mixed (PennyLane-0.40.0.dev49)
- default.qubit (PennyLane-0.40.0.dev49)
- default.qutrit (PennyLane-0.40.0.dev49)
- default.qutrit.mixed (PennyLane-0.40.0.dev49)
- default.tensor (PennyLane-0.40.0.dev49)
- null.qubit (PennyLane-0.40.0.dev49)
- reference.qubit (PennyLane-0.40.0.dev49)
- qrack.simulator (pennylane-qrack-0.11.1)
- bluequbit.cpu (bluequbit-0.9.3b1)
- lightning.kokkos (PennyLane_Lightning_Kokkos-0.40.0.dev41)
- cirq.mixedsimulator (PennyLane-Cirq-0.40.0.dev0)
- cirq.pasqal (PennyLane-Cirq-0.40.0.dev0)
- cirq.qsim (PennyLane-Cirq-0.40.0.dev0)
- cirq.qsimh (PennyLane-Cirq-0.40.0.dev0)
- cirq.simulator (PennyLane-Cirq-0.40.0.dev0)
- qulacs.simulator (pennylane-qulacs-0.40.0.dev0)

Source code and tracebacks

N/A

Additional information

N/A