"density matrix" meaning in English

{
  "forms": [
    {
      "form": "density matrices",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "density matrices"
      },
      "expansion": "density matrix (plural density matrices)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Quantum mechanics",
          "orig": "en:Quantum mechanics",
          "parents": [
            "Physics",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A matrix that describes the quantum state of a physical system."
      ],
      "id": "en-density_matrix-en-noun-BPqRTfng",
      "links": [
        [
          "quantum mechanics",
          "quantum mechanics"
        ],
        [
          "matrix",
          "matrix"
        ],
        [
          "describe",
          "describe"
        ],
        [
          "quantum state",
          "quantum state"
        ],
        [
          "physical system",
          "physical system"
        ]
      ],
      "qualifier": "quantum mechanics",
      "raw_glosses": [
        "(quantum mechanics) A matrix that describes the quantum state of a physical system."
      ]
    }
  ],
  "word": "density matrix"
}

{
  "forms": [
    {
      "form": "density matrices",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "density matrices"
      },
      "expansion": "density matrix (plural density matrices)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Quantum mechanics"
      ],
      "glosses": [
        "A matrix that describes the quantum state of a physical system."
      ],
      "links": [
        [
          "quantum mechanics",
          "quantum mechanics"
        ],
        [
          "matrix",
          "matrix"
        ],
        [
          "describe",
          "describe"
        ],
        [
          "quantum state",
          "quantum state"
        ],
        [
          "physical system",
          "physical system"
        ]
      ],
      "qualifier": "quantum mechanics",
      "raw_glosses": [
        "(quantum mechanics) A matrix that describes the quantum state of a physical system."
      ]
    }
  ],
  "word": "density matrix"
}