Cal. Code Civ. Proc. § 613
When the case is finally submitted to the jury, they may decide in court or retire for deliberation. If they retire, they must be kept together in some convenient place, under charge of an officer, until at least three-fourths of them agree upon a verdict or are discharged by the court. Unless by order of the court, the officer having them under his or her charge shall not permit any communication to be made to them, including any form of electronic or wireless communication, or make any himself or herself, except to ask them if they or three-fourths of them are agreed upon a verdict. The officer shall not, before their verdict is rendered, communicate to any person the state of their deliberations, or the verdict agreed upon.
Ca. Civ. Proc. Code § 613