Question: When did the current central bank of the country that conducted the Castle Bravo test start quantitative easing?

full_context: Document 1: Quantitative easing: The US Federal Reserve belatedly implemented policies similar to the current quantitative easing during the Great Depression of the 1930s. Specifically, banks' excess reserves exceeded 6 percent in 1940, whereas they vanished during the entire postwar period until 2008. Despite this fact, many commentators called the scope of the Federal Reserve quantitative easing program after the 2008 crisis ``unprecedented ''.
Document 2: Nuclear weapon design: A spherical secondary can achieve higher implosion densities than a cylindrical secondary, because spherical implosion pushes in from all directions toward the same spot. However, in warheads yielding more than one megaton, the diameter of a spherical secondary would be too large for most applications. A cylindrical secondary is necessary in such cases. The small, cone-shaped re-entry vehicles in multiple-warhead ballistic missiles after 1970 tended to have warheads with spherical secondaries, and yields of a few hundred kilotons.
Document 3: Great Depression: The Great Depression was a severe worldwide economic depression that took place mostly during the 1930s, originating in the United States. The timing of the Great Depression varied across nations; in most countries it started in 1929 and lasted until 1941. It was the longest, deepest, and most widespread depression of the 20th century. In the 21st century, the Great Depression is commonly used as an example of how far the world's economy can decline.
Document 4: Thermonuclear weapon: The first full - scale thermonuclear test was carried out by the United States in 1952; the concept has since been employed by most of the world's nuclear powers in the design of their weapons. The modern design of all thermonuclear weapons in the United States is known as the Teller -- Ulam configuration for its two chief contributors, Edward Teller and Stanislaw Ulam, who developed it in 1951 for the United States, with certain concepts developed with the contribution of John von Neumann. Similar devices were developed by the Soviet Union, United Kingdom, France, and China.
Document 5: Federal Reserve: The Federal Reserve System is composed of several layers. It is governed by the presidentially appointed Board of Governors or Federal Reserve Board (FRB). Twelve regional Federal Reserve Banks, located in cities throughout the nation, oversee the privately owned U.S. member banks. Nationally chartered commercial banks are required to hold stock in the Federal Reserve Bank of their region, which entitles them to elect some of their board members. The Federal Open Market Committee (FOMC) sets monetary policy; it consists of all seven members of the Board of Governors and the twelve regional bank presidents, though only five bank presidents vote at any given time: the president of the New York Fed and four others who rotate through one - year terms. There are also various advisory councils. Thus, the Federal Reserve System has both public and private components. The structure is considered unique among central banks. It is also unusual in that the United States Department of the Treasury, an entity outside of the central bank, prints the currency used.
Document 6: Nuclear weapon design: It was much more difficult to understand how it worked or why it failed. Designers gathered as much data as possible during the explosion, before the device destroyed itself, and used the data to calibrate their models, often by inserting fudge factors into equations to make the simulations match experimental results. They also analyzed the weapon debris in fallout to see how much of a potential nuclear reaction had taken place.
Document 7: Federal Reserve: The Federal Reserve System (also known as the Federal Reserve or simply the Fed) is the central banking system of the United States. It was created on December 23, 1913, with the enactment of the Federal Reserve Act, after a series of financial panics (particularly the panic of 1907) led to the desire for central control of the monetary system in order to alleviate financial crises. Over the years, events such as the Great Depression in the 1930s and the Great Recession during the 2000s have led to the expansion of the roles and responsibilities of the Federal Reserve System.
Document 8: United States dollar: The value of the U.S. dollar declined significantly during wartime, especially during the American Civil War, World War I, and World War II. The Federal Reserve, which was established in 1913, was designed to furnish an "elastic" currency subject to "substantial changes of quantity over short periods", which differed significantly from previous forms of high-powered money such as gold, national bank notes, and silver coins. Over the very long run, the prior gold standard kept prices stable—for instance, the price level and the value of the U.S. dollar in 1914 was not very different from the price level in the 1880s. The Federal Reserve initially succeeded in maintaining the value of the U.S. dollar and price stability, reversing the inflation caused by the First World War and stabilizing the value of the dollar during the 1920s, before presiding over a 30% deflation in U.S. prices in the 1930s.
Document 9: Nuclear weapon design: The picture below shows the Shrimp device, detonated on March 1, 1954 at Bikini, as the Castle Bravo test. Its 15-megaton explosion was the largest ever by the United States. The silhouette of a man is shown for scale. The device is supported from below, at the ends. The pipes going into the shot cab ceiling, which appear to be supports, are actually diagnostic light pipes. The eight pipes at the right end (1) sent information about the detonation of the primary. Two in the middle (2) marked the time when x-radiation from the primary reached the radiation channel around the secondary. The last two pipes (3) noted the time radiation reached the far end of the radiation channel, the difference between (2) and (3) being the radiation transit time for the channel.
Document 10: Federal Reserve: The Federal Reserve System (also known as the Federal Reserve or simply the Fed) is the central banking system of the United States of America. It was created on December 23, 1913, with the enactment of the Federal Reserve Act, after a series of financial panics (particularly the panic of 1907) led to the desire for central control of the monetary system in order to alleviate financial crises. Over the years, events such as the Great Depression in the 1930s and the Great Recession during the 2000s have led to the expansion of the roles and responsibilities of the Federal Reserve System.
Document 11: United States dollar: When the Federal Reserve makes a purchase, it credits the seller's reserve account (with the Federal Reserve). This money is not transferred from any existing funds—it is at this point that the Federal Reserve has created new high-powered money. Commercial banks can freely withdraw in cash any excess reserves from their reserve account at the Federal Reserve. To fulfill those requests, the Federal Reserve places an order for printed money from the U.S. Treasury Department. The Treasury Department in turn sends these requests to the Bureau of Engraving and Printing (to print new dollar bills) and the Bureau of the Mint (to stamp the coins).
Document 12: Marshall Islands: During the early years of the Cold War from 1946 to 1958, the United States tested 67 nuclear weapons at its Pacific Proving Grounds located in the Marshall Islands, including the largest atmospheric nuclear test ever conducted by the U.S., code named Castle Bravo. "The bombs had a total yield of 108,496 kilotons, over 7,200 times more powerful than the atomic weapons used during World War II." With the 1952 test of the first U.S. hydrogen bomb, code named "Ivy Mike," the island of Elugelab in the Enewetak atoll was destroyed. In 1956, the United States Atomic Energy Commission regarded the Marshall Islands as "by far the most contaminated place in the world."
Document 13: Federal Reserve Act: The Federal Reserve Act (ch. 6, 38 Stat. 251, enacted December 23, 1913, 12 U.S.C. ch. 3) is an Act of Congress that created and established the Federal Reserve System, the central banking system of the United States, and which created the authority to issue Federal Reserve Notes (now commonly known as the U.S. Dollar) and Federal Reserve Bank Notes as legal tender. The Act was signed into law by President Woodrow Wilson.
Document 14: Federal Reserve Bank: The twelve regional Federal Reserve Banks were established as the operating arms of the nation's central banking system. They are organized much like private corporations -- possibly leading to some confusion about ownership.
Document 15: Federal Reserve Act: The Federal Reserve Act (ch. 6, 38 Stat. 251, enacted December 23, 1913, 12 U.S.C. § § 221 to 522) is an Act of Congress that created and established the Federal Reserve System (the central banking system of the United States), and which created the authority to issue Federal Reserve Notes (commonly known as the US Dollar) as legal tender. The Act was signed into law by President Woodrow Wilson.
ground_truth: during the Great Depression of the 1930s
sub_queries: What country conducted the Castle Bravo test? Answer: United States
the current central bank of United States is Answer: Federal Reserve
when did Federal Reserve start quantitative easing Answer: during the Great Depression of the 1930s