California Code, Code of Civil Procedure - CCP § 1283.2

Except for the parties to the arbitration and their agents, officers and employees, all witnesses appearing pursuant to subpoena are entitled to receive fees and mileage in the same amount and under the same circumstances as prescribed by law for witnesses in civil actions in the superior court. The fee and mileage of a witness subpoenaed upon the application of a party to the arbitration shall be paid by such party. The fee and mileage of a witness subpoenaed solely upon the determination of the neutral arbitrator shall be paid in the manner provided for the payment of the neutral arbitrator's expenses.