# Quantum State Validity Checker

> Quantum State Validity Checker is a paid API for AI agents from www.mahastrategies.com, paid per call via x402, $0.014001/call, status unknown (last checked 2026-10-13).

Validates a single-qubit complex density matrix for unit trace, Hermiticity, and positive semidefiniteness with configurable tolerance.

## Facts

- Endpoint: POST https://www.mahastrategies.com/api/v1/micro/quantum-state-validity?utm_source=zero.xyz
- Price: $0.014001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quantum-state-validity-checker-c3a8ea72
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wmMnlnSZ6hOVb-wkW_3b3

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability quantum-state-validity-checker-c3a8ea72 -d '<json body>'
```

Example prompt: Check whether this single-qubit density matrix [[0.7, 0.1+0.2i], [0.1-0.2i, 0.3]] is a valid quantum state — verify unit trace, Hermiticity, and positive semidefiniteness, treating the data as synthetic.

## When to prefer this

Use this endpoint when you need a lightweight, deterministic, software-only validation of a single-qubit density matrix against all three standard quantum state validity conditions (unit trace, Hermiticity, positive semidefiniteness) without any quantum hardware involvement. Prefer it over manual linear algebra checks or general-purpose math libraries when you want an explicit tolerance-aware pass/fail result with structured output suitable for agent workflows.

## Known failure modes

- Matrix not square or not 2x2 — rejected as invalid single-qubit format
- Trace deviates beyond tolerance — fails unit trace check
- Off-diagonal elements not complex conjugates — fails Hermiticity check
- Negative eigenvalue detected — fails positive semidefiniteness check
- Missing required fields (state or dataClass) — schema validation error
- Invalid dataClass enum value — request rejected

## How this service works

Check a supplied single-qubit complex density matrix for unit trace, Hermiticity and positive semidefiniteness with explicit tolerance; no hardware validation.

## Output

Returns a structured result object indicating whether the density matrix passed or failed each validity check (unit trace, Hermiticity, positive semidefiniteness), along with boundary values, an offer ID, version, input digest, receipt digest, and amount charged in base units.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "dataClass",
      "state"
     ],
     "properties": {
      "state": {
       "type": "object"
      },
      "dataClass": {
       "enum": [
        "public",
        "synthetic"
       ],
       "type": "string"
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "version",
      "offerId",
      "amountBaseUnits",
      "inputDigest",
      "result",
      "boundaries",
      "receiptDigest"
     ],
     "properties": {
      "result": {
       "type": "object"
      },
      "offerId": {
       "enum": [
        "quantum-state-validity"
       ],
       "type": "string"
      },
      "version": {
       "enum": [
        "maha-microproducts/0.1"
       ],
       "type": "string"
      },
      "boundaries": {
       "type": "array",
       "maxItems": 128,
       "minItems": 0
      },
      "inputDigest": {
       "type": "string",
       "maxLength": 71
      },
      "receiptDigest": {
       "type": "string",
       "maxLength": 71
      },
      "amountBaseUnits": {
       "enum": [
        "14001"
       ],
       "type": "string"
      }
     },
     "additionalProperties": false
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/quantum-state-validity-checker-c3a8ea72/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from www.mahastrategies.com](https://www.zero.xyz/host/www.mahastrategies.com/llms.txt)