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In a quantum many-body system coupled to the environment, its steady state can exhibit spontaneous symmetry breaking when a control parameter exceeds a critical value. In this study, we consider spontaneous symmetry breaking in non-steady modes of an open quantum many-body system. Assuming that the time evolution of the density matrix of the system is described by a Markovian master equation, the dynamics of the system is fully characterized by the eigenmodes and spectrum of the corresponding time evolution superoperator. Among the non-steady eigenmodes with finite lifetimes, we focus on the eigenmodes with the highest frequency, which we call the most coherent mode. For a dissipative spin model, it is shown that the most coherent mode exhibits a transition from a disordered phase to a symmetry-broken ordered phase, even if the steady state does not show singular behavior. We further argue that the phase transition of the most coherent mode induces a qualitative change in the decoherence dynamics of highly entangled states, i.e., the Schr\"odinger's cat states., Comment: 10 pages, 7 figures

Information on the implementation of continuous renal replacement therapy (CRRT) in pediatric intensive care units (PICUs) is limited. We investigated the real-world practice of this therapy in Japan.We conducted a cross-sectional survey of 26 hospitals with PICUs in Japan. One physician per hospital responded to the questionnaire.Fewer than half of the hospitals followed the CRRT practice guidelines; treatment options were often selected at a physician's discretion. PICUs varied widely in continuous renal replacement settings, circuit priming methods, frequency of circuit exchange, and policies for using CRRT in sepsis. Only two anticoagulants were used: nafamostat mesylate and unfractionated heparin. Most units did not change the nutritional dosage according to CRRT use. Many facilities were proactive concerning rehabilitation.Nafamostat-centered anticoagulation management was unique to Japan. Our results may help identify areas where additional clinical studies are needed to standardize CRRT practice.

Objective The use of pediatric rapid response systems (RRSs) to improve the safety of hospitalized children has spread in various western countries including the United States and the United Kingdom. We aimed to determine the prevalence and characteristics of pediatric RRSs and barriers to use in Japan, where epidemiological information is limited. Design A cross-sectional online survey. Setting All 34 hospitals in Japan with pediatric intensive care units (PICUs) in 2019. Participants One PICU physician per hospital responded to the questionnaire as a delegate. Main outcome measures Prevalence of pediatric RRSs in Japan and barriers to their use. Results The survey response rate was 100%. Pediatric RRSs had been introduced in 14 (41.2%) institutions, and response teams comprised a median of 6 core members. Most response teams employed no full-time members and largely comprised members from multiple disciplines and departments who served in addition to their main duties. Of 20 institutions without pediatric RRSs, 11 (55%) hoped to introduce them, 14 (70%) had insufficient knowledge concerning them and 11 (55%) considered that their introduction might be difficult. The main barrier to adopting RRSs was a perceived personnel and/or funding shortage. There was no significant difference in hospital beds (mean, 472 vs. 524, P = 0.86) and PICU beds (mean, 10 vs. 8, P = 0.34) between institutions with/without pediatric RRSs. Conclusions Fewer than half of Japanese institutions with PICUs had pediatric RRSs. Operating methods for and obstructions to RRSs were diverse. Our findings may help to popularize pediatric RRSs.

Patients with congenital heart disease who have a variety of cardiac/extracardiac problems are at high risk for deterioration. This study aimed to determine the effectiveness of post-intensive care unit (ICU) follow-up by a rapid response team (RRT) after congenital heart surgery. This before-and-after study was conducted at an urban regional tertiary hospital. We enrolled 572 consecutive patients who underwent congenital heart surgery and were transferred alive from the paediatric ICU (PICU) between April 2015 and March 2020. Post-ICU follow-up for 48 h was started in April 2018. The primary and secondary endpoints were unplanned ICU readmission and clinical outcomes at ICU readmission, respectively. Overall, 346 and 226 patients were analysed pre- and post-intervention, respectively. Patient demographics were similar between groups, but in the post-intervention group, patients tended to have had more complicated surgery. Unplanned ICU readmission rates within 30 days were similar between groups. Regarding the demographics and outcomes at ICU readmission, patients in the post-intervention group had lower predicted mortality rates (1.7% vs 5.3%, P = 0.001), required less ventilator days (median, 0.5 days [interquartile range (IQR) 0–1] vs median, 3 days [IQR 0.5–4], P = 0.02), and had a shorter ICU stay (median, 3 days [IQR 2–4] vs median, 6 days [IQR 3–9], P = 0.03), but there was no significant between-group difference in ICU mortality. Post-ICU follow-up by a RRT after congenital heart surgery did not decrease unplanned ICU readmission but improved several outcomes at ICU readmission.

While there are no clear indications for body temperature control during viral infections such as COVID‐19, if heat stress caused by COVID‐19 leads to organ failure, then proactive body temperature regulation may be an effective treatment option., The patient's remittent fever changed to sustained fever on hospitalization day 9. * addition of continuous renal replacement therapy to the patient's treatment. ** addition of VA‐ECMO.

Coronavirus disease (COVID-19) is an emerging infectious disease. There may be a correlation between heatstroke and severity of COVID-19. In cases where heat stress caused by COVID-19 promotes organ failure, the proactive regulation of body temperature may be considered as an effective treatment option.

Objectives To evaluate the characteristics of patients with congenital heart disease requiring ICU admission from emergency departments and determine the associations between the reasons for emergency department visits and specific congenital heart disease types or cardiac procedures. Design Retrospective observational study using data from a Japanese multicenter database. Setting Twelve PICUs and 11 general ICUs in Japan. Patients All patients requiring ICU admission from an emergency department during 2013-2018, divided into two groups: with congenital heart disease and without congenital heart disease groups. Interventions None for this analysis. Measurements and main results Of the 297 patients with congenital heart disease (9.2% of a total of 3,240 patients), more than half had moderate-to-high complexity congenital heart disease; most of them were pediatric patients who had visited specialized congenital heart disease centers. All the patients' clinical outcomes were similar. Regarding the reasons for emergency department admission, seizure was significantly associated with a single ventricle anatomy (odds ratio, 3.3; 95% CI, 1.1-10.0), post-Glenn shunt placement (odds ratio, 5.6; 95% CI, 1.1-29.4), and a Fontan-type operation status (odds ratio, 6.3; 95% CI, 1.5-25.5). Sepsis and gastrointestinal bleeding were associated with asplenia (odds ratio, 21.1; 95% CI, 4.3-104 and odds ratio, 21.0; 95% CI, 3.1-141, respectively); gastrointestinal bleeding was also associated with systemic-to-pulmonary artery shunt placement (odds ratio, 18.8; 95% CI, 2.8-125) and a Fontan-type operation status (odds ratio, 17.0; 95% CI, 2.6-112). Arrhythmia was associated with a single ventricle anatomy (odds ratio, 21.0; 95% CI, 3.1-141), systemic-to-pulmonary artery shunt placement (odds ratio, 18.8; 95% CI, 2.8-125), and a Fontan-type operation status (odds ratio, 17.0; 95% CI, 2.6-112). Conclusions Classification of the reasons for emergency department admission by congenital heart disease type and surgical stage may guide clinicians in the selection of appropriate treatments in such settings.

It is highly nontrivial to what extent we can deduce the relaxation behavior of a quantum dissipative system from the spectral gap of the Liouvillian that governs the time evolution of the density matrix. We investigate the relaxation processes of a quantum dissipative system that exhibits the Liouvillian skin effect, which means that the eigenmodes of the Liouvillian are localized exponentially close to the boundary of the system, and find that the timescale for the system to reach a steady state depends not only on the Liouvillian gap $\Delta$ but also on the localization length $\xi$ of the eigenmodes. In particular, we show that the longest relaxation time $\tau$ that is maximized over initial states and local observables is given by $\tau \sim \Delta^{-1}(1+L/\xi)$ with $L$ being the system size. This implies that the longest relaxation time can diverge for $L \to \infty$ without gap closing., Comment: 15 pages, 10 figures

The spatial fluctuations of a superfluid flowing in a weak random potential are investigated. We employ classical field theory to demonstrate that the disorder-averaged nonequilibrium second-order correlation of the order parameter at zero temperature is identical to the thermally averaged equilibrium counterpart of a uniform superfluid at an effective temperature. The physics behind this equivalence is that scattering of a moving condensate by disorder has the same effect on the correlation function as equilibrium thermal excitations. The correlation function exhibits an exponential decay in one dimension and a power-law decay in two dimensions. We show that the effective temperature can be measured in an interference experiment of ultracold atomic gases., 10 pages, 3 figures

The indications for using temporary epicardial pacing wires after pediatric cardiac surgery remain unclear. Post-procedure intracardiac pressure is valuable for detecting circulatory disturbances and residual lesions. This study aimed to examine the association between post-procedure intracardiac pressures and the use of temporary epicardial pacing wires. We performed a retrospective, case–control study at the pediatric intensive care unit of an urban regional tertiary hospital that included patients who had undergone congenital heart surgery between January 2015 and December 2016. We measured post-procedure intracardiac pressures, and data regarding baseline characteristics, procedures performed, and intraoperative variables were collected as covariates. Of the 186 included patients, 34 (18.3%) were treated using temporary epicardial pacing wires. The optimal cutoff values used to predict the use of pacing wires for central venous pressure, left atrial pressure, pulmonary arterial pressure/systemic blood pressure ratio, and right ventricular pressure/left ventricular pressure ratio were 11 mmHg (55.6% sensitivity, 86.2% specificity), 13 mmHg (50% sensitivity, 84.6% specificity), 0.39 (69.6% sensitivity, 78.7% specificity), and 0.51 (74.1% sensitivity, 64.2% specificity), respectively. Multivariable logistic regression analyses showed that the use of temporary epicardial pacing wires was significantly associated with left atrial pressure ≥ 11 mmHg (odds ratio 4.4; 95% confidence interval 1.01–18.9), and a pulmonary arterial pressure/systemic blood pressure ratio ≥ 0.39 (odds ratio 6.3; 95% confidence interval 1.3–31.4). High post-procedure intracardiac pressures were associated with the use of temporary epicardial pacing wires. These data can aid in the decision-making for the proper use of temporary epicardial pacing wires.

The Floquet-Magnus expansion is a useful tool to calculate an effective Hamiltonian for periodically driven systems. In this study, we investigate the convergence of the expansion for a one-body nonlinear system in a continuous space, a driven anharmonic oscillator. In this model, all eigenstates of the time evolution operator are found to be localized in energy space, and the expectation value of the energy is bounded from above. We first propose a general procedure to estimate the radius of convergence of the Floquet-Magnus expansion for periodically driven systems with an unbounded energy spectrum. By applying it to the driven anharmonic oscillator, we numerically show that the expansion diverges for all driving frequencies even if the anharmonicity is arbitrarily small. This conclusion contradicts the widely accepted belief that the divergence of the Floquet-Magnus expansion is a direct consequence of quantum ergodicity, which implies that each eigenstate of the time evolution operator is a linear combination of all available eigenstates of the unperturbed Hamiltonian and the system heats up to infinite temperature after long intervals., 13 pages, 8 figures

We review the functional renormalization group treatment in disordered systems. In this theory, one follows the flow of the whole functional form of the renormalized disorder correlator. We explain that its nonanalytic behavior leads to the breakdown of the dimensional reduction. As well-known examples, we derive the one-loop functional renormalization group equations for the random manifold and random field O(N) models, and discuss the properties of their fixed points.

We consider the driven random field XY model. The dimensional reduction predicts that this model exhibits the Kosterlitz-Thouless transition in three dimensions. We investigate this remarkable conjecture by using numerical simulations and renormalization group analysis. In the first part of this chapter, we show several results of the numerical simulations of the driven random field XY model. These results suggest that there is a transition between a quasi-long-range order phase at weak disorder and a disordered phase at strong disorder. The second half of this chapter is devoted to the functional renormalization group analysis of this model. Within the spin-wave approximation, the driven random field XY model is shown to exhibit a quasi-long-range order with a nonuniversal exponent at weak disorder. We also construct a phenomenological theory of the three-dimensional Kosterlitz-Thouless transition by taking into account the effect of topological defects.

We review the nonperturbative renormalization group theory. This approach is based on an exact flow equation of the effective action and it enables us to investigate critical phenomena which cannot be described by perturbative treatments. We first explain the general formulation of this theory and we next demonstrate how it is applied to the pure and random field O(N) models.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members.As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines., other authors: Satoru Hashimoto,Daisuke Hasegawa,Junji Hatakeyama,Naoki Hara,Naoki Higashibeppu,Nana Furushima,Hirotaka Furusono,Yujiro Matsuishi,Tasuku Matsuyama,Yusuke Minematsu,Ryoichi Miyashita,Yuji Miyatake,Megumi Moriyasu,Toru Yamada,Hiroyuki Yamada,Ryo Yamamoto,Takeshi Yoshida,Yuhei Yoshida,Jumpei Yoshimura,Ryuichi Yotsumoto,Hiroshi Yonekura,Takeshi Wada,Eizo Watanabe,Makoto Aoki,Hideki Asai,Takakuni Abe,Yutaka Igarashi,Naoya Iguchi,Masami Ishikawa,Go Ishimaru,Shutaro Isokawa,Ryuta Itakura,Hisashi Imahase,Haruki Imura,Takashi Irinoda,Kenji Uehara,Noritaka Ushio,Takeshi Umegaki,Yuko Egawa,Yuki Enomoto,Kohei Ota,Yoshifumi Ohchi,Takanori Ohno,Hiroyuki Ohbe,Kazuyuki Oka,Nobunaga Okada,Yohei Okada,Hiromu Okano,Jun Okamoto,Hiroshi Okuda,Takayuki Ogura,Yu Onodera,Yuhta Oyama,Motoshi Kainuma,Eisuke Kako,Masahiro Kashiura,Hiromi Kato,Akihiro Kanaya,Tadashi Kaneko,Keita Kanehata,Ken-ichi Kano,Hiroyuki Kawano,Kazuya Kikutani,Hitoshi Kikuchi,Takahiro Kido,Sho Kimura,Hiroyuki Koami,Daisuke Kobashi,Iwao Saiki,Masahito Sakai,Ayaka Sakamoto,Tetsuya Sato,Yasuhiro Shiga,Manabu Shimoto,Shinya Shimoyama,Tomohisa Shoko,Yoh Sugawara,Atsunori Sugita,Satoshi Suzuki,Yuji Suzuki,Tomohiro Suhara,Kenji Sonota,Shuhei Takauji,Kohei Takashima,Sho Takahashi,Yoko Takahashi,Jun Takeshita,Yuuki Tanaka,Akihito Tampo,Taichiro Tsunoyama,Kenichi Tetsuhara,Kentaro Tokunaga,Yoshihiro Tomioka,Kentaro Tomita,Naoki Tominaga,Mitsunobu Toyosaki,Yukitoshi Toyoda,Hiromichi Naito,Isao Nagata,Tadashi Nagato,Yoshimi Nakamura,Yuki Nakamori,Isao Nahara,Hiromu Naraba,Chihiro Narita,Norihiro Nishioka,Tomoya Nishimura,Kei Nishiyama,Tomohisa Nomura,Taiki Haga,Yoshihiro Hagiwara,Katsuhiko Hashimoto,Takeshi Hatachi,Toshiaki Hamasaki,Takuya Hayashi,Minoru Hayashi,Atsuki Hayamizu,Go Haraguchi,Yohei Hirano,Ryo Fujii,Motoki Fujita,Naoyuki Fujimura,Hiraku Funakoshi,Masahito Horiguchi,Jun Maki,Naohisa Masunaga,Yosuke Matsumura,Takuya Mayumi,Keisuke Minami,Yuya Miyazaki,Kazuyuki Miyamoto,Teppei Murata,Machi Yanai,Takao Yano,Kohei Yamada,Naoki Yamada,Tomonori Yamamoto,Shodai Yoshihiro,Hiroshi Tanaka,Osamu Nishida, Guidelines

We investigate the critical velocity of a weakly interacting Bose gas flowing in a random potential. By applying the Bogoliubov theory to a disordered Bose system with a steady flow, we determine the critical velocity for weak and moderate disorder. We also calculate the superfluid density and the condensate density as a function of the disorder strength and the flow velocity, and their behaviors near the critical velocity are discussed.

We demonstrate a three-dimensional Kosterlitz-Thouless (KT) transition in the random field XY model driven out of thermal equilibrium. By employing the spin-wave approximation and functional renormalization group approach, in the weak disorder regime, the three-dimensional driven random field XY model is found to exhibit a quasi-long-range order phase, wherein the correlation function shows power-law decay with a non-universal exponent that depends on the disorder strength. This result is consistent with that reported in a previous numerical study. We further develop a phenomenological theory of the three-dimensional KT transition by taking into account the effect of vortices. The point of this theory is that the cross-section of the system with respect to a plane perpendicular to the driving direction is essentially identical to the two-dimensional pure XY model., 16 pages, 6 figures

The critical behavior of the random field $O(N)$ model driven at a uniform velocity is investigated at zero-temperature. From naive phenomenological arguments, we introduce a dimensional reduction property, which relates the large-scale behavior of the $D$-dimensional driven random field $O(N)$ model to that of the $(D-1)$-dimensional pure $O(N)$ model. This is an analogue of the dimensional reduction property in equilibrium cases, which states that the large-scale behavior of $D$-dimensional random field models is identical to that of $(D-2)$-dimensional pure models. However, the dimensional reduction property breaks down in low enough dimensions due to the presence of multiple meta-stable states. By employing the non-perturbative renormalization group approach, we calculate the critical exponents of the driven random field $O(N)$ model near three-dimensions and determine the range of $N$ in which the dimensional reduction breaks down., Comment: 20 pages, 7 figures

We investigate the critical behavior of disordered systems transversely driven at a uniform and steady velocity. An intuitive argument predicts that the long-distance physics of $D$-dimensional driven disordered systems at zero temperature is the same as that of the corresponding $(D-1)$-dimensional pure systems in thermal equilibrium. This result is analogous to the well-known dimensional reduction property in thermal equilibrium, which states the equivalence between $D$-dimensional disordered systems and $(D-2)$-dimensional pure systems. To clarify the condition that the dimensional reduction holds, we perform the functional renormalization group analysis of elastic manifolds transversely driven in random media. We argue that the nonanalytic behavior in the second cumulant of the renormalized disorder leads to the breakdown of the dimensional reduction. We further found that the roughness exponent is equal to the dimensional reduction value for the single component case, but it is not for the multi-component cases., Comment: 27 pages, 3 figures

We investigate the stability and critical velocity of a weakly interacting Bose gas flowing in a random potential. By applying the Bogoliubov theory to a disordered Bose system with a steady flow, the condensate density and the superfluid density are determined as functions of the disorder strength, flow velocity, and temperature. The critical velocity, at which the steady flow becomes unstable, is calculated from the spectrum of hydrodynamic excitation. We also show that in two dimensions the critical velocity strongly depends on the system size., 18 pages, 5 figures

We investigate three-dimensional O(N) spin models driven with a uniform velocity over a random field. Within a spin-wave approximation, it is shown that in the strong driving regime the model with N=2 exhibits a quasi-long-range order in which the spatial correlation function decays in a power-law form. Furthermore, for the cases that N=2 and 3, we numerically demonstrate a non-equilibrium phase transition between the quasi-long-range order phase and the disordered phase, which turns out to resemble the Kosterlitz-Thouless transition in the two-dimensional pure XY model in equilibrium., 9pages, 8figures

著者人数: 11名, 資料番号: SA1003505000

We have searched for orthoposition decay into {gamma} plus a feebly interacting boson {ital X}{sup 0}, by looking for a narrow peak in the energy spectrum of single {gamma} taken under the condition of no additional {gamma} detected in a hermetic photon detector. No evidence of such decay is observed, resulting in a new upper limit on the branching ratio of 1.1{times}10{sup {minus}6}, which is a factor of 60 more stringent than previous limits in the {ital m}{sub {ital x}} region below 30 keV. This experiment rules out the existence of light ({ital m}{sub {ital X}}{lt}800 GeV) Goldstone-like bosons having electron-coupling constants {alpha}{sub {ital X}{ital e}{ital e}} larger than 1.1{times}10{sup {minus}11}.

Motivated by the recently reported discrepancy between measured and theoretical values for the orthopositronium lifetime, we have searched for exotic decay of orthopositronium into \ensuremath{\gamma} plus a long-lived neutral particle X, in the hitherto unexplored mass region of ${m}_{x}$ below 100 keV. Our negative result provides new upper limits of 6.4\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$ to 7.6\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}6}$ on the branching ratio of such decay. Consequently we exclude the hypothesis of Samuel, i.e., that a new pseudoscalar particle with mass less than 5.7 keV is responsible for the discrepancy of the orthopositronium lifetime.