Struct Qubit 

pub struct Qubit { /* private fields */ }

A single-qubit pure state: |ψ⟩ = α|0⟩ + β|1⟩.

Invariant: |α|² + |β|² = 1 (up to floating-point tolerance).

Implementations

impl Qubit

pub fn new(alpha: Complex<f64>, beta: Complex<f64>) -> QuantumResult<Self>

Construct a qubit from raw amplitudes, normalising automatically.

Returns an error if the norm is zero (unphysical).

pub fn new_zero() -> Self

|0⟩ state.

pub fn new_one() -> Self

|1⟩ state.

pub fn new_superposition(theta: f64, phi: f64) -> Self

Bloch-sphere parametrisation: |ψ⟩ = cos(θ/2)|0⟩ + e^{iφ} sin(θ/2)|1⟩.

• theta ∈ [0, π]: polar angle.
• phi ∈ [0, 2π): azimuthal angle.

pub fn new_plus() -> Self

Equal superposition: (|0⟩ + |1⟩) / √2.

pub fn new_minus() -> Self

Equal superposition: (|0⟩ − |1⟩) / √2.

pub fn alpha(&self) -> Complex<f64>

Amplitude for |0⟩.

pub fn beta(&self) -> Complex<f64>

Amplitude for |1⟩.

pub fn prob_zero(&self) -> f64

Probability of measuring |0⟩.

pub fn prob_one(&self) -> f64

Probability of measuring |1⟩.

pub fn is_normalised(&self, tol: f64) -> bool

Check normalisation; returns true if within tol of 1.

pub fn measure<R: Rng>(&self, rng: &mut R) -> (u8, Qubit)

Perform a projective measurement in the computational basis.

Returns (outcome, post_measurement_state) where outcome is 0 or 1 and the post-measurement state has collapsed to the corresponding basis state.

Uses rng to sample the Born-rule distribution.

pub fn bloch_angles(&self) -> (f64, f64)

Bloch-sphere angles (theta, phi) for this qubit.

Returns (theta, phi) where θ ∈ [0, π] and φ ∈ [0, 2π).

pub fn to_register(&self) -> QubitRegister

Convert this single-qubit state into a QubitRegister.

Trait Implementations

impl Clone for Qubit

fn clone(&self) -> Qubit

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Qubit

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Qubit

fn default() -> Self

Returns the “default value” for a type.

impl Display for Qubit

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Qubit

fn eq(&self, other: &Qubit) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Qubit