The Instantaneous Bethe-Salpeter Equation and Its Analog: the Breit-like Equation

We take ($\mu^\pm e^\mp$) systems and consider the states with quantum number $J^P=0^-$ as examples, to explore the different contents of the instantaneous Bethe-Salpeter (BS) equation and its analog, Breit equation, by solving them exactly. The results show that the two equations are not equivalent, although they are analogous. Furthermore, we point out that the Breit equation contains extra un-physical solutions, so it should be abandoned if one wishes to have an accurate description of the bound states for the instantaneous interacting binding systems.Comment: 5 pages, no figur

Experiment (II)

Translated by Sufen Sophia La

Monte Carlo Method for a Quantum Measurement Process by a Single-Electron Transistor

We derive the quantum trajectory or stochastic (conditional) master equation for a single superconducting Cooper-pair box (SCB) charge qubit measured by a single-electron transistor (SET) detector. This stochastic master equation describes the random evolution of the measured SCB qubit density matrix which both conditions and is conditioned on a particular realization of the measured electron tunneling events through the SET junctions. Hence it can be regarded as a Monte Carlo method that allows us to simulate the continuous quantum measurement process. We show that the master equation for the "partially" reduced density matrix [Y. Makhlin et.al., Phys. Rev. Lett. 85, 4578 (2000)] can be obtained when a "partial" average is taken on the stochastic master equation over the fine grained measurement records of the tunneling events in the SET. Finally, we present some Monte Carlo simulation results for the SCB/SET measurement process. We also analyze the probability distribution P(m,t) of finding m electrons that have tunneled into the drain of the SET in time t to demonstrate the connection between the quantum trajectory approach and the "partially" reduced density matrix approach.Comment: 7 pages, to appear in Phys. Rev.

Hadronic production of the PP-wave excited BcB_c-states (BcJ,L=1∗B_{cJ,L=1}^*)

Adopting the complete $\alpha_s^4$ approach of the perturbative QCD (pQCD) and updated parton distribution functions, we have estimated the hadronic production of $P$-wave excited $B_c$-states ($B_{cJ,L=1}^*$). In the estimate, special care on the relation of the production amplitude to the derivative of wave function at origin of the potential model is payed. For experimental references, main uncertainties are discussed, and the total cross sections and the distributions of the production with reasonable cuts at the energies of Tevatron and LHC are computed and presented. The results show that $P$-wave production may contribute to the $B_c$-meson production indirectly by a factor about 0.5 of the direct production, and with such a big cross section, it is worth further to study the possibility to observe the $P$-wave production itself experimentally.Comment: 23 pages, 9 figures, to replace for revising the misprints ec

Disrupting the Path from Childhood Trauma to Juvenile Justice: An Upstream Health and Justice Approach

A groundbreaking public health study funded by the U.S. Centers for Disease Control and Prevention (CDC) and the Kaiser Foundation found astoundingly high rates of childhood trauma, including experiences like abuse, neglect, parental substance abuse, mental illness, and incarceration. Hundreds of follow-up studies have revealed that multiple traumatic adverse childhood experiences (or “ACEs”) make it far more likely that a person will have poor mental health outcomes in adulthood, such as higher rates of depression, anxiety, suicide attempts, and substance abuse. Interestingly, the original ACE Study examined a largely middle-class adult population living in San Diego, but subsequent follow-up studies have examined the prevalence of ACEs and its impact on mental health in other populations, including among people involved in the juvenile and criminal justice systems. Unsurprisingly, individuals entangled in those systems are more likely to have experienced higher numbers of these traumatic events, despite a frequent lack of access to critical mental health treatment, including the treatment necessary to address past childhood trauma. The ACEs framework for understanding health and mental health outcomes resulting from childhood trauma has received a high level of attention recently following an in-depth, multi-part series on these issues by National Public Radio (NPR) and other media. Because the ACEs public health research shows us that events in childhood can cause “toxic stress” and have a lasting impact on the mental health of a child well into adulthood, this framework provides us with an opportunity to consider how to more effectively intervene to stop the pathway from ACEs to juvenile justice system involvement and address the related health, mental health, developmental, and legal needs of children and their families. Before a child becomes an adult facing a mental health crisis or incarceration, attorneys, doctors, and other professionals can collaborate to disrupt that fate. This Article argues for a more upstream approach to address mental health using a medical-legal collaboration, based on the experiences of the authors, a law professor and medical school professor who work together to try to improve outcomes for children who have experienced trauma and their families. In Part I, we begin by examining the groundbreaking ACE studies, exploring the toxic stress and health and mental health outcomes that are associated with high rates of ACEs in childhood. Next, in Part II, we analyze the research revealing high rates of trauma and ACEs among populations involved in the juvenile justice system. Finally, we conclude in Part III by arguing for a more upstream public health and justice approach. We examine a particular problem in the city of Albuquerque, the largest urban area in New Mexico: children who have a particular ACE right from birth in the form of substance abuse by a household member. These infants are born with prenatal drug exposure and many experience symptoms of withdrawal in their first weeks of life, often quickly followed by an accumulation of additional forms of early childhood trauma. We discuss an approach through which the authors work to address those issues and disrupt the path from that childhood trauma to poor outcomes and juvenile justice system involvement. This approach engages attorneys with doctors and other health and developmental professionals to address ACEs among young children ages zero to three and their siblings, parents, and other caregivers. We advocate for an early, holistic, multi-generational, multi-disciplinary public health and justice approach to address ACEs early and improve the trajectory for children who have experienced childhood trauma