The fundamental limit on the rate of quantum dynamics: the unified bound is tight

The question of how fast a quantum state can evolve has attracted a considerable attention in connection with quantum measurement, metrology, and information processing. Since only orthogonal states can be unambiguously distinguished, a transition from a state to an orthogonal one can be taken as the elementary step of a computational process. Therefore, such a transition can be interpreted as the operation of "flipping a qubit", and the number of orthogonal states visited by the system per unit time can be viewed as the maximum rate of operation. A lower bound on the orthogonalization time, based on the energy spread DeltaE, was found by Mandelstam and Tamm. Another bound, based on the average energy E, was established by Margolus and Levitin. The bounds coincide, and can be exactly attained by certain initial states if DeltaE=E; however, the problem remained open of what the situation is otherwise. Here we consider the unified bound that takes into account both DeltaE and E. We prove that there exist no initial states that saturate the bound if DeltaE is not equal to E. However, the bound remains tight: for any given values of DeltaE and E, there exists a one-parameter family of initial states that can approach the bound arbitrarily close when the parameter approaches its limit value. The relation between the largest energy level, the average energy, and the orthogonalization time is also discussed. These results establish the fundamental quantum limit on the rate of operation of any information-processing system.Comment: 4 pages 1 PS figure Late

The Consumer Financial Protection Agency

Examines the current regulatory structures for consumer financial services protection, its limitations, and concerns about the proposal to consolidate consumer protection functions under one agency with research, rule-making, and enforcement authority

Abusive Credit Card Practices and Bankruptcy: Hearing Before the S. Comm. on the Judiciary, 111th Cong., March 24, 2009 (Statement of Associate Professor Adam J. Levitin, Geo. U. L. Center)

The Marquette decision created a regulatory arbitrage possibility that set off a regulatory race to the bottom. Congress should act to close this loophole. There is a reasonable debate to be had on usury regulations, but that is one that should be held in legislatures, not determined by the Supreme Court\u27s interpretation of a hoary statute. A 1970s interpretation of an 1863 law should not be what determines 21st century consumer credit regulation. Congress should permit the states, the laboratories of democracy, to go further than S.257 if they wish in regulating high-interest-rate consumer credit. This essential consumer protection power should be restored to the states. S.257 offers an important protection to consumers and responsible creditors, eliminates an incentive to game the bankruptcy system, and encourages responsible lending. These protections will help ensure fairer, safer, and sounder consumer credit. Now, more than ever, consumers and creditors need reforms that will create a fair and sustainable credit system. I urge the Congress to pass S.257

H.R. 200, the Helping Families Save Their Homes in Bankruptcy Act of 2009, and H.R. 225, the Emergency Homeownership and Equity Protection Act : Hearing Before the H. Comm. on the Judiciary, 111th Cong., Jan. 22, 2009 (Statement of Associate Professor Adam J. Levitin, Geo. U. L. Center)

Permitting modification of all mortgages in bankruptcy would create a low-cost, effective, fair, and immediately available method for resolving much of the current foreclosure crisis without imposing costs on taxpayers, creating a moral hazard for borrowers or lenders, or increasing mortgage credit costs or decreasing mortgage credit availability. As the foreclosure crisis deepens, bankruptcy modification presents the best and least invasive method of stabilizing the housing market and is a crucial step in stabilizing financial markets

Problems in Mortgage Servicing from Modification to Foreclosure: Hearing Before the S. Comm. on Banking, Housing, & Urban Affairs, 111th Cong., Nov. 16, 2010 (Statement of Associate Professor Adam J. Levitin, Geo. U. L. Center)

The mortgage foreclosure process is beset by a variety of problems. These range from procedural defects (including, but not limited to robosigning) to outright counterfeiting of documents to questions about the validity of private-label mortgage securitizations that could mean that these mortgage-backed securities are not actually backed by any mortgages whatsoever. While the extent of these problems is unknown at present, the evidence is mounting that it is not limited to one-off cases, but that there may be pervasive defects throughout the foreclosure and securitization processes. The problems in the mortgage market are highly technical, but they are extremely serious. At best they present problems of fraud on the court, clouded title to property, and delay in foreclosures that will increase the shadow housing inventory and drive down home prices. At worst, they represent a systemic risk of liabilities in the trillions of dollars, greatly exceeding the capital of the US’s major financial institutions. Congress would do well to ensure that federal regulators are undertaking a thorough investigation of foreclosure problems and to consider the possibilities for a global settlement of foreclosure problems, loan modifications, and the housing debt overhang that stagnate the economy and pose potential systemic risk

The Paper Chase: Securitization, Foreclosure, and the Uncertainty of Mortgage Title

The mortgage foreclosure crisis raises legal questions as important as its economic impact. Questions that were straightforward and uncontroversial a generation ago today threaten the stability of a $13 trillion mortgage market: Who has standing to foreclose? If a foreclosure was done improperly, what is the effect? And what is the proper legal method for transferring mortgages? These questions implicate the clarity of title for property nationwide and pose a too-big-to-fail problem for the courts. The legal confusion stems from the existence of competing systems for establishing title to mortgages and transferring those rights. Historically, mortgage title was established and transferred through the public demonstration regimes of UCC Article 3 and land recordation systems. This arrangement worked satisfactorily when mortgages were rarely transferred. Mortgage finance, however, shifted to securitization, which involves repeated bulk transfers of mortgages. To facilitate securitization, deal architects developed alternative contracting regimes for mortgage title: UCC Article 9 and MERS, a private mortgage registry. These new regimes reduced the cost of securitization by dispensing with demonstrative formalities, but at the expense of reduced clarity of title, which raised the costs of mortgage enforcement. This trade-off benefitted the securitization industry at the expense of securitization investors because it became apparent only subsequently with the rise in mortgage foreclosures. The harm, however, has not been limited to securitization investors. Clouded mortgage title has significant negative externalities on the economy as a whole. This Article proposes reconciling the competing title systems through an integrated system of note registration and mortgage recordation, with compliance as a prerequisite to foreclosure. Such a system would resolve questions about standing, remove the potential cloud to real-estate title, and facilitate mortgage financing by clarifying property rights

Robo-Signing, Chain of Title, Loss Mitigation, and Other Issues in Mortgage Servicing: Hearing Before the Subcomm. on Hous. and Cmty. Opportunity of the H. Fin. Serv. Comm., 111th Cong., Nov. 18, 2010 (Statement of Associate Professor Adam J. Levitin, Geo. U. L. Center)

The US is now in its forth year of a mortgage crisis in which over 3 million families have lost their homes and another 2.5 million are currently scheduled to lose theirs. Repeated government loan modification or refinancing initiatives have failed miserably. To this sad state of affairs, there now come a variety of additional problems: faulty foreclosures due to irregularities ranging from procedural defects (including, but not limited to robosigning) to outright counterfeiting of documents; predatory servicing practices that precipitate borrower defaults and then overcharge for foreclosure services that are ultimately paid for by investors; and questions about the validity of transfers in private-label mortgage securitizations. While the extent of these problems is unknown at present, the evidence is mounting that they are not limited to one-off cases, but that there may be pervasive defects throughout the mortgage servicing and securitization processes

Home Foreclosures: Will Voluntary Mortgage Modification Help Families Save Their Homes? Part II? : Hearing Before the H. Comm. on the Judiciary Subcomm. on Commercial and Administrative Law, 111th Cong., Dec. 11, 2009 (Statement of Associate Professor Adam J. Levitin, Geo. U. L. Center)

The results to date from MHAP are deeply disappointing. Even the most optimistic view of HAMP and HARP’s potential would now project the programs as having only a minor impact on the foreclosure crisis. Until and unless the problems of unemployment; negative equity, and servicer capacity, incentives, and contract restrictions are addressed, we are unlikely to see noticeably different results. These issues cannot be addressed within the current structure of HAMP. Unfortunately, none of the solutions for foreclosures due to unemployment are particularly satisfying, and without addressing unemployment, foreclosures will remain at elevated levels. Bankruptcy presents possible solutions to negative equity as well as to servicer-side problems of capacity, incentives, and contractual restrictions, as it removes servicers from the modification business. A bankruptcy solution is not a silver bullet that will end the foreclosure crisis, but if negative equity and servicer-side problems can be successfully addressed, it will result in significant progress in foreclosure mitigation