qudit

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Qudit Quickstart ​

Get up and running with qudit, a Python library for working with d-level quantum systems (qudits): with circuits, error correction, and QML style workflows.

Installation ​

I recommend using a virtual environment (e.g., venv or conda) to manage your Python dependencies since qudit will install torch which may conflict with any existing global installations. Install from PyPI:

bash
pip install qudit

If you’re working in a notebook:

bash
python -m pip install qudit

Verify your install ​

bash
python -c "from qudit.random import random_state; print(random_state(2))"

Core ideas ​

  • A qudit has dimension d (e.g., d=2 qubit, d=3 qutrit).
  • A state can be represented as a complex vector |ψ⟩ or density matrix ρ.
  • An operator is a d×d matrix (unitary gates, observables, channels).
  • A register of n qudits has dimension dn.

Circuit-less Bell state ​

python
from qudit import Basis, State
from qudit.circuit import Gategen

G = Gategen(2)
Ket = Basis(2)

Psi = Ket("00")
print(Psi)

HI = G.H ^ G.I
CX = G.CX

# CX H⊗I |00> = (|00> + |11>) / sqrt(2)
Psi = CX @ HI @ Psi
# [0.7071, 0, 0, 0.7071]
print(Psi)

Circuit Bell state ​

python
from qudit import Basis, State
from qudit.circuit import Circuit


Ket = Basis(2)
C = Circuit(wires=2, dim=2)
G = C.gates[2]
# or G = Gategen(2)

Psi = Ket("00")

C.gate(G.H, [0])
C.gate(G.CX, [0, 1])
Psi = C(Psi)

Should you choose to print the circuit with print(C.draw()), you will see a nice ASCII representation of the circuit.

|0> [2] ┤─H─╭●─┤
|0> [2] ┤───╰U─┤

Which shows us we start with two dits of dimension two, apply a Hadamard gate to the first qudit, and then a CNOT gate between the first and second qudit.

Citation ​

txt
M. Seksaria, A. Mishra and A. Prabhakar, "qudit: High-Performance Simulator for Qudit Systems," 2025 Supercomputing India (SCI), Bangalore, India, 2025, pp. 1-7, doi: 10.1109/SCI68648.2025.11333840. keywords: {Quantum system;Machine learning algorithms;Codes;Qubit;Machine learning;Probabilistic logic;Libraries;Error correction;Integrated circuit modeling;Quantum simulation},
bib
@INPROCEEDINGS{11333840,
  author={Seksaria, Manav and Mishra, Abhyuday and Prabhakar, Anil},
  booktitle={2025 Supercomputing India (SCI)},
  title={qudit: High-Performance Simulator for Qudit Systems},
  year={2025},
  volume={},
  number={},
  pages={1-7},
  keywords={Quantum system;Machine learning algorithms;Codes;Qubit;Machine learning;Probabilistic logic;Libraries;Error correction;Integrated circuit modeling;Quantum simulation},
  doi={10.1109/SCI68648.2025.11333840}
}
txt
TY  - CONF
TI  - qudit: High-Performance Simulator for Qudit Systems
T2  - 2025 Supercomputing India (SCI)
SP  - 1
EP  - 7
AU  - M. Seksaria
AU  - A. Mishra
AU  - A. Prabhakar
PY  - 2025
DO  - 10.1109/SCI68648.2025.11333840
JO  - 2025 Supercomputing India (SCI)
IS  -
SN  -
VO  -
VL  -
JA  - 2025 Supercomputing India (SCI)
Y1  - 9-13 Dec. 2025
ER  -