Is there any relationship between the state of employee's mind and productivity?

Yes, disengaged employees are much more likely to be less productive and prone to more human errors.

YES THERE IS POSITIVE RELATIONHIP BETWEEN THESE TWO FACTORS. THE MIND STATE OF AN EMPLOYEE MAY BE CONTROLLED BY WELFARE SUCH AS HEALTH SERVICES, ACCOMMODATION, TRANSPORT SERVICES, OVER TIME BENEFITS, PENSION AND GRATUITY. ALSO THE INCOME PACKAGE, TRAINING, WORKING FACILITIES AND WORKING ENVIRONMENT.