Is there a level of interest rates low enough to avoid a public debt crisis and high enough to avoid asset price bubbles?

To avoid a public debt crisis, government bond yields must be lower than nominal potential growth. To avoid an equity bubble, long-term interest rates plus a normal equity risk premium must be higher than nominal long-term growth; and to avoid a real estate bubble, long-term interest rates on mortgage loans must be higher than nominal long-term growth. This makes it possible to define the risk-free long-term interest rate level that prevents both public debt crises and asset price bubbles. In the United States, it ranges (for the 10-year interest rate) between 2.3% and 4%; in the euro zone, between 1.8% and 2.8%. These two objectives (no public debt crisis, no bubbles) can therefore be achieved if long-term interest rates stabilise between these levels.