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Peres–Horodecki criterion

Test bipartite quantum-state separability by partially transposing one subsystem and checking positivity, a necessary condition in all dimensions and a sufficient one only for 2×2 and 2×3 systems.

Version
v1 · 2026-09-08 · History
Domain-specific #
6037
Origin domain
quantum information
Subdomain
entanglement detection
Aliases
PPT criterion, Positive partial transpose criterion

Core Idea

The Peres-Horodecki or PPT criterion says every separable bipartite state has positive semidefinite partial transpose; positivity is also sufficient for separability in 2×2 and 2×3 dimensions. Partial transpose preserves positivity of each product-state term but can reveal negative eigenvalues created by entangled coherences. In higher dimensions PPT entangled bound states exist, so a positive result can be inconclusive. The abstraction is therefore identified by a declared carrier, a transformation or constraint over that carrier, and an invariant that tells an analyst whether the named structure is genuinely present.

Scope of Application

Peres–Horodecki criterion belongs to quantum information and is useful where the analyst can specify a bipartite density operator ρ on H_A⊗H_B, a chosen product basis for matrix transposition, eigenvalues of the partial transpose, and subsystem dimensions, then evaluate ρ is a valid density operator, partial transpose is taken on one specified subsystem, positivity is checked numerically or analytically, and dimensional sufficiency is not extended beyond 2×2 or 2×3. The scope is broad within that domain but bounded by the need for ρ is a valid density operator, partial transpose is taken on one specified subsystem, positivity is checked numerically or analytically, and dimensional sufficiency is not extended beyond 2×2 or 2×3.

Clarity

The abstraction clarifies a crowded vocabulary by making ρ is a valid density operator, partial transpose is taken on one specified subsystem, positivity is checked numerically or analytically, and dimensional sufficiency is not extended beyond 2×2 or 2×3 the center of the account. A claim should name the carrier, the governing operation or relation, the applicable assumptions, and the recognition test.

Manages Complexity

Without the abstraction, an analyst must reason directly over many local details: the carrier roles, admissibility assumptions, competing conventions, derived invariants, boundary cases, and proof or validation obligations specific to Peres–Horodecki criterion. Peres–Horodecki criterion compresses them into the roles in the structural signature. That compression permits comparison across instances without erasing the variables that determine validity. It also exposes which details may be varied safely and which are constitutive.

Abstract Reasoning

  1. Identify the carrier. State what the elements, states, objects, or observations are: a bipartite density operator ρ on H_A⊗H_B, a chosen product basis for matrix transposition, eigenvalues of the partial transpose, and subsystem dimensions. Reject examples whose alleged carrier belongs to a different problem. 2.

Knowledge Transfer

Knowledge transfers strongly among subfields of quantum information because they reuse a bipartite density operator ρ on H_A⊗H_B, a chosen product basis for matrix transposition, eigenvalues of the partial transpose, and subsystem dimensions, Partial transpose preserves positivity of each product-state term but can reveal negative eigenvalues created by entangled coherences. In higher dimensions PPT entangled bound states exist, so a positive result can be inconclusive., and type the carrier, state every parameter and convention in the definition, test that ρ is a valid density operator, partial transpose is taken on one specified subsystem, positivity is checked numerically or analytically, and dimensional sufficiency is not extended beyond 2×2 or 2×3, compare the nearest accepted identity, and report counterexamples, uncertainty, and limiting cases.

Relationships to Other Abstractions

Local relationship map for Peres–Horodecki criterionParents appear above the current abstraction, mutual partners to the right, and children below. Node labels state whether each abstraction is prime or domain-specific; colors identify relation types.Peres–HorodeckicriterionDOMAINPrime abstraction: Hypothesis Testing (Null vs. Alternative) — is a kind ofHypothesis Test…PRIME

Current abstraction Peres–Horodecki criterion Domain-specific

Parents (1) — more general patterns this builds on

Neighborhood in Abstraction Space

Peres–Horodecki criterion sits in a crowded region of the domain-specific corpus (26th percentile for distinctiveness): several abstractions share nearly its structure, so a description that fits it tends to fit its neighbors too.

Family — Quantum Information & State Structure (41 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-09-08