class="copy-paste-block">NEW HAVEN – Predictably, the European Central Bank has joined the world’s other major monetary authorities in the greatest experiment in the history of central banking. By now, the pattern is all too familiar. First, central banks take the conventional policy rate down to the dreaded “zero bound.” Facing continued economic weakness, but having run out of conventional tools, they then embrace the unconventional approach of quantitative easing (QE).