Struct Ket

Source

pub struct Ket<R: RealScalar> { /* private fields */ }

Expand description

Represents a quantum state vector as a Ket.

Implementations§

Source §

impl<R: RealScalar> Ket<R>

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pub fn new<T: Into<Radices>, V: Into<Self>>(radices: T, vector: V) -> Self

Create a new Ket.

§Arguments

radices - The radices of the qudit system.
vector - The vector to wrap.

§Panics

Panics if the vector is not a pure state.

§Example

use faer::Col;
use qudit_core::Ket;
use qudit_core::c64;
let zero_state: Ket<f64> = Ket::new([2, 2], vec![
    c64::ONE, c64::ZERO, c64::ZERO, c64::ZERO
]);

§See Also

Source

pub fn zero<T: Into<Radices>>(radices: T) -> Self

Create a zero state (all amplitudes zero).

§Arguments

radices - The radices of the qudit system.

§Example

use qudit_core::Ket;
let zero_state: Ket<f64> = Ket::zero([2, 2]);

Source

pub fn basis<T: Into<Radices>>(radices: T, index: usize) -> Self

Create a computational basis state |i⟩.

§Arguments

radices - The radices of the qudit system.
index - The computational basis index.

§Panics

Panics if the index is out of bounds for the given radices.

§Example

use qudit_core::Ket;
let state: Ket<f64> = Ket::basis([2, 2], 3); // |11⟩ state

Source

pub fn uniform<T: Into<Radices>>(radices: T) -> Self

Create a uniform superposition state (all amplitudes equal).

§Arguments

radices - The radices of the qudit system.

§Example

use qudit_core::Ket;
let uniform_state: Ket<f64> = Ket::uniform([2, 2]);

Source

pub fn is_pure_state(&self) -> bool

Check if this is a valid normalized pure quantum state.

A pure state must have norm² ≈ 1.0 (normalized).

§Arguments

tolerance - Optional tolerance for normalization check (default: 1e-10)

§Example

use qudit_core::Ket;
let basis_state: Ket<f64> = Ket::basis([2, 2], 0);
assert!(basis_state.is_pure_state());

Source

pub fn get_distance_from(&self, other: &Self) -> R

Get the distance from another quantum state.

This computes 1 - |⟨ψ|φ⟩|² where |⟨ψ|φ⟩|² is the fidelity. Distance of 0 means identical states, distance of 1 means orthogonal states.

§Arguments

other - The other quantum state to compare with

§Panics

Panics if the states have different dimensions.

§Example

use qudit_core::Ket;
let state1: Ket<f64> = Ket::basis([2], 0);
let state2: Ket<f64> = Ket::basis([2], 1);
let distance = state1.get_distance_from(&state2);
assert!((distance - 1.0).abs() < 1e-10); // Orthogonal states

Source

pub fn probabilities(&self) -> Vec<R>

Get the probabilities for all computational basis states.

Returns a vector where each element is |amplitude|² for the corresponding basis state.

§Example

use qudit_core::Ket;
let uniform_state: Ket<f64> = Ket::uniform([2, 2]);
let probs = uniform_state.probabilities();
// Each probability should be 0.25 for uniform superposition

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pub fn probability_at(&self, index: usize) -> R

Get the probability of measuring the state in a specific computational basis state.

§Arguments

index - The computational basis index

§Panics

Panics if the index is out of bounds.

§Example

use qudit_core::Ket;
let basis_state: Ket<f64> = Ket::basis([2, 2], 1);
assert!((basis_state.probability_at(1) - 1.0).abs() < 1e-10);
assert!(basis_state.probability_at(0).abs() < 1e-10);

Source

pub fn tensor_product(&self, other: &Self) -> Self

Compute the tensor product with another quantum state.

Creates a new state |ψ⟩ ⊗ |φ⟩ representing a composite quantum system.

§Arguments

other - The other quantum state to tensor with

§Example

use qudit_core::Ket;
let qubit1: Ket<f64> = Ket::basis([2], 0); // |0⟩
let qubit2: Ket<f64> = Ket::basis([2], 1); // |1⟩
let combined = qubit1.tensor_product(&qubit2); // |01⟩