RESUMO
The phenomena of quantum criticality underlie many novel collective phenomena found in condensed matter systems. They present a challenge for classical and quantum simulation, in part because of diverging correlation lengths and consequently strong finite-size effects. Tensor network techniques that work directly in the thermodynamic limit can negotiate some of these difficulties. Here, we optimise a translationally invariant, sequential quantum circuit on a superconducting quantum device to simulate the groundstate of the quantum Ising model through its quantum critical point. We further demonstrate how the dynamical quantum critical point found in quenches of this model across its quantum critical point can be simulated. Our approach avoids finite-size scaling effects by using sequential quantum circuits inspired by infinite matrix product states. We provide efficient circuits and a variety of error mitigation strategies to implement, optimise and time-evolve these states.
RESUMO
OBJECTIVE: To investigate whether bereaved next of kin would like to have been present in the resuscitation room during attempted cardiopulmonary resuscitation of their relative, and their experience or knowledge of what is involved in cardiopulmonary resuscitation. METHODS: The next of kin of patients who had recently died after unsuccessful cardiopulmonary resuscitation in the accident and emergency department were contacted initially by telephone and then sent a postal questionnaire. RESULTS: Four (11%) of 35 respondents had been asked whether they wished to be present in the resuscitation room; 24 (69%) would like to have been offered the opportunity, even though not all would have accepted. The respondents had a wide variety of perceptions of what happens during resuscitation, few of which corresponded to clinical practice. CONCLUSIONS: Most relatives of patients requiring cardiopulmonary resuscitation would like to be offered the possibility of being in the resuscitation room; this could have several benefits.